68 results on '"Tantin D"'
Search Results
2. Pou2af1 Is a Novel Regulator of Airway EpithelialCells Differentiation and Response to Fibrotic Injury
- Author
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Li, Q., primary, Omote, N., additional, Adams, T., additional, Chioccioli, M., additional, Shakya, A., additional, DeIuliis, G., additional, Herzog, E., additional, Tantin, D., additional, Herazo-Maya, J.D., additional, and Kaminski, N., additional
- Published
- 2019
- Full Text
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3. Deletion of Pou2af1 in Type II Alveolar Epithelial Cells Augments Bleomycin-Induced Pulmonary Fibrosis
- Author
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Li, Q., primary, Omote, N., additional, Chen, Z., additional, DeIuliis, G., additional, Zhu, Z., additional, Herzog, E., additional, Shakya, A., additional, Tantin, D., additional, Herazo-Maya, J.D., additional, and Kaminski, N., additional
- Published
- 2019
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- View/download PDF
4. An allergy-associated polymorphism in a novel regulatory element enhances IL13 expression
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Kiesler, P., primary, Shakya, A., additional, Tantin, D., additional, and Vercelli, D., additional
- Published
- 2009
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5. The requirement for the basal transcription factor IIE is determined by the helical stability of promoter DNA.
- Author
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Holstege, F.C., primary, Tantin, D., additional, Carey, M., additional, van der Vliet, P.C., additional, and Timmers, H.T., additional
- Published
- 1995
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6. A heteroduplex template circumvents the energetic requirement for ATP during activated transcription by RNA polymerase II
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Tantin, D., primary and Carey, M., additional
- Published
- 1994
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7. RNA polymerase II elongation complexes containing the Cockayne syndrome group B protein interact with a molecular complex containing the transcription factor IIH components xeroderma pigmentosum B and p62.
- Author
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Tantin, D
- Abstract
Transcription factor IIH (TFIIH) is involved both in transcription initiation by RNA polymerase II and in nucleotide excision-repair. Nucleotide excision-repair occurs at higher rates in transcriptionally active regions of the genome. Genetic studies indicate that this transcription-coupled repair is dependent on the Cockayne syndrome group A and B proteins, as well as TFIIH subunits. Previous work indicated that Cockayne syndrome group B interacts with RNA polymerase II molecules engaged in ternary complexes containing DNA and RNA. Evidence presented here indicates that this complex can interact with a factor containing the TFIIH core subunits p62 and xeroderma pigmentosum subunit B/excision repair cross-complementing 3. The targeting of TFIIH or a TFIIH-like repair factor to transcriptionally active DNA indicates a potential mechanism for transcription-coupled repair in human cells.
- Published
- 1998
8. Recruitment of the putative transcription-repair coupling factor CSB/ERCC6 to RNA polymerase II elongation complexes.
- Author
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Tantin, D, Kansal, A, and Carey, M
- Abstract
Cockayne's syndrome (CS) is a disease characterized by developmental and growth defects, sunlight sensitivity, and a defect in transcription-coupled nucleotide excision repair. The two principle proteins involved in CS, CSA and CSB/ERCC6, have been hypothesized to bind RNA polymerase II (Pol II) and link transcription to DNA repair. We have tested CSA and CSB in assays designed to determine their role in transcription-coupled repair. Using a unique oligo(dC)-tailed DNA template, we provide biochemical evidence that CSB/ERCC6 interacts with Pol II molecules engaged in ternary complexes containing DNA and nascent RNA. CSB is a DNA-activated ATPase, and hydrolysis of the ATP beta-gamma phosphoanhydride bond is required for the formation of a stable Pol II-CSB-DNA-RNA complex. Unlike CSB, CSA does not directly bind Pol II.
- Published
- 1997
9. Oct4 redox sensitivity potentiates reprogramming and differentiation.
- Author
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Shen Z, Wu Y, Manna A, Yi C, Cairns BR, Evason KJ, Chandrasekharan MB, and Tantin D
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- Animals, Mice, Embryonic Stem Cells cytology, Embryonic Stem Cells metabolism, Tretinoin pharmacology, Tretinoin metabolism, Gene Expression Regulation, Developmental genetics, Humans, Octamer Transcription Factor-3 metabolism, Octamer Transcription Factor-3 genetics, Oxidation-Reduction, Cell Differentiation genetics, Cellular Reprogramming genetics
- Abstract
The transcription factor Oct4/Pou5f1 is a component of the regulatory circuitry governing pluripotency and is widely used to induce pluripotency from somatic cells. Here we used domain swapping and mutagenesis to study Oct4's reprogramming ability, identifying a redox-sensitive DNA binding domain, cysteine residue (Cys48), as a key determinant of reprogramming and differentiation. Oct4 Cys48 sensitizes the protein to oxidative inhibition of DNA binding activity and promotes oxidation-mediated protein ubiquitylation. Pou5f1
C48S point mutation has little effect on undifferentiated embryonic stem cells (ESCs) but upon retinoic acid (RA) treatment causes retention of Oct4 expression, deregulated gene expression, and aberrant differentiation. Pou5f1C48S ESCs also form less differentiated teratomas and contribute poorly to adult somatic tissues. Finally, we describe Pou5f1C48S ( Janky ) mice, which in the homozygous condition are severely developmentally restricted after E4.5. Rare animals bypassing this restriction appear normal at birth but are sterile. Collectively, these findings uncover a novel Oct4 redox mechanism involved in both entry into and exit from pluripotency., (© 2024 Shen et al.; Published by Cold Spring Harbor Laboratory Press.)- Published
- 2024
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10. OCA-B promotes autoimmune demyelination through control of stem-like CD4 + T cells.
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Hughes EP, Syage AR, Mehrabad EM, Lane TE, Spike BT, and Tantin D
- Abstract
Stem-like T cell populations can selectively contribute to autoimmunity, but the activities that promote and sustain these populations are incompletely understood. Here, we show that T cell-intrinsic loss of the transcription cofactor OCA-B protects mice from experimental autoimmune encephalomyelitis (EAE) while preserving responses to CNS infection. In adoptive transfer EAE models driven by multiple antigen encounters, OCA-B deletion nearly eliminates CNS infiltration, proinflammatory cytokine production and clinical disease. OCA-B-expressing CD4
+ T cells within the CNS of mice with EAE comprise a minority of the population but display a memory phenotype and preferentially confer disease. In a relapsing-remitting EAE model, OCA-B T cell deficiency specifically protects mice from relapse. During remission, OCA-B promotes the expression of Tcf7 , Slamf6 , and Sell in proliferating T cell populations. At relapse, OCA-B loss results in both the accumulation of an immunomodulatory CD4+ T cell population expressing Ccr9 and Bach2 , and the loss of pro-inflammatory gene expression from Th17 cells. These results identify OCA-B as a driver of pathogenic stem-like T cells.- Published
- 2024
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11. Durable CD4 + T cell immunity: cherchez la stem.
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Hughes EP, Syage AR, and Tantin D
- Subjects
- Animals, Humans, Immunologic Memory, Mammals, CD4-Positive T-Lymphocytes, Autoimmunity
- Abstract
Mammalian stem cells govern development, tissue homeostasis, and regeneration. Following years of study, their functions have been delineated with increasing precision. The past decade has witnessed heightened widespread use of stem cell terminology in association with durable T cell responses to infection, antitumor immunity, and autoimmunity. Interpreting this literature is complicated by the fact that descriptions are diverse and criteria for labeling 'stem-like' T cells are evolving. Working under the hypothesis that conceptual frameworks developed for actual stem cells can be used to better evaluate and organize T cells described to have stem-like features, we outline widely accepted properties of stem cells and compare these to different 'stem-like' CD4
+ T cell populations., Competing Interests: Declaration of interests No interests are declared., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
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12. OCA-B/Pou2af1 is sufficient to promote CD4 + T cell memory and prospectively identifies memory precursors.
- Author
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Sun W, Hughes EP, Kim H, Perovanovic J, Charley KR, Perkins B, Du J, Ibarra A, Syage AR, Hale JS, Williams MA, and Tantin D
- Subjects
- Animals, Mice, Immunologic Memory, Memory, Receptors, Interleukin-7, Trans-Activators, GADD45 Proteins, Antigens, Differentiation, Memory T Cells, CD4-Positive T-Lymphocytes
- Abstract
The molecular mechanisms leading to the establishment of immunological memory are inadequately understood, limiting the development of effective vaccines and durable antitumor immune therapies. Here, we show that ectopic OCA-B expression is sufficient to improve antiviral memory recall responses, while having minimal effects on primary effector responses. At peak viral response, short-lived effector T cell populations are expanded but show increased Gadd45b and Socs2 expression, while memory precursor effector cells show increased expression of Bcl2 , Il7r, and Tcf7 on a per-cell basis. Using an OCA-B mCherry reporter mouse line, we observe high OCA-B expression in CD4
+ central memory T cells. We show that early in viral infection, endogenously elevated OCA-B expression prospectively identifies memory precursor cells with increased survival capability and memory recall potential. Cumulatively, the results demonstrate that OCA-B is both necessary and sufficient to promote CD4 T cell memory in vivo and can be used to prospectively identify memory precursor cells., Competing Interests: Competing interests statement:The authors declare no competing interest.- Published
- 2024
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13. Oct1 cooperates with the Smad family of transcription factors to promote mesodermal lineage specification.
- Author
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Perovanovic J, Wu Y, Abewe H, Shen Z, Hughes EP, Gertz J, Chandrasekharan MB, and Tantin D
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- Animals, Mice, Cell Differentiation, Binding Sites, Mesoderm metabolism, Cell Lineage, Transcription Factors metabolism, Embryonic Stem Cells
- Abstract
The transition between pluripotent and tissue-specific states is a key aspect of development. Understanding the pathways driving these transitions will facilitate the engineering of properly differentiated cells for experimental and therapeutic uses. Here, we showed that during mesoderm differentiation, the transcription factor Oct1 activated developmental lineage-appropriate genes that were silent in pluripotent cells. Using mouse embryonic stem cells (ESCs) with an inducible knockout of Oct1, we showed that Oct1 deficiency resulted in poor induction of mesoderm-specific genes, leading to impaired mesodermal and terminal muscle differentiation. Oct1-deficient cells exhibited poor temporal coordination of the induction of lineage-specific genes and showed inappropriate developmental lineage branching, resulting in poorly differentiated cell states retaining epithelial characteristics. In ESCs, Oct1 localized with the pluripotency factor Oct4 at mesoderm-associated genes and remained bound to those loci during differentiation after the dissociation of Oct4. Binding events for Oct1 overlapped with those for the histone lysine demethylase Utx, and an interaction between Oct1 and Utx suggested that these two proteins cooperate to activate gene expression. The specificity of the ubiquitous Oct1 for the induction of mesodermal genes could be partially explained by the frequent coexistence of Smad and Oct binding sites at mesoderm-specific genes and the cooperative stimulation of mesodermal gene transcription by Oct1 and Smad3. Together, these results identify Oct1 as a key mediator of mesoderm lineage-specific gene induction.
- Published
- 2023
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14. Antibody-Mediated Targeting of a Hybrid Insulin Peptide Toward Neonatal Thymic Langerin-Positive Cells Enhances T-Cell Central Tolerance and Delays Autoimmune Diabetes.
- Author
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Lin Y, Perovanovic J, Kong Y, Igyarto BZ, Zurawski S, Tantin D, Zurawski G, Bettini M, and Bettini ML
- Subjects
- Animals, Antibodies, Autoantigens, Central Tolerance, Insulin, Insulin, Regular, Human, Mice, Mice, Inbred NOD, Peptides, Thymus Gland, Diabetes Mellitus, Type 1
- Abstract
Thymic presentation of self-antigens is critical for establishing a functional yet self-tolerant T-cell population. Hybrid peptides formed through transpeptidation within pancreatic β-cell lysosomes have been proposed as a new class of autoantigens in type 1 diabetes (T1D). While the production of hybrid peptides in the thymus has not been explored, due to the nature of their generation, it is thought to be highly unlikely. Therefore, hybrid peptide-reactive thymocytes may preferentially escape thymic selection and contribute significantly to T1D progression. Using an antibody-peptide conjugation system, we targeted the hybrid insulin peptide (HIP) 2.5HIP toward thymic resident Langerin-positive dendritic cells to enhance thymic presentation during the early neonatal period. Our results indicated that anti-Langerin-2.5HIP delivery can enhance T-cell central tolerance toward cognate thymocytes in NOD.BDC2.5 mice. Strikingly, a single dose treatment with anti-Langerin-2.5HIP during the neonatal period delayed diabetes onset in NOD mice, indicating the potential of antibody-mediated delivery of autoimmune neoantigens during early stages of life as a therapeutic option in the prevention of autoimmune diseases., (© 2022 by the American Diabetes Association.)
- Published
- 2022
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15. Tet2 coordinates with Foxo1 and Runx1 to balance T follicular helper cell and T helper 1 cell differentiation.
- Author
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Baessler A, Novis CL, Shen Z, Perovanovic J, Wadsworth M, Thiede KA, Sircy LM, Harrison-Chau M, Nguyen NX, Varley KE, Tantin D, and Hale JS
- Subjects
- Cell Differentiation genetics, Lymphocyte Activation, T-Lymphocytes, Helper-Inducer, Germinal Center, T Follicular Helper Cells
- Abstract
In response to various types of infection, naïve CD4
+ T cells differentiate into diverse helper T cell subsets; however, the epigenetic programs that regulate differentiation in response to viral infection remain poorly understood. Demethylation of CpG dinucleotides by Tet methylcytosine dioxygenases is a key component of epigenetic programing that promotes specific gene expression, cellular differentiation, and function. We report that following viral infection, Tet2-deficient CD4+ T cells preferentially differentiate into highly functional germinal center T follicular helper (TFH ) cells that provide enhanced help for B cells. Using genome-wide DNA methylation and transcription factor binding analyses, we find that Tet2 coordinates with multiple transcription factors, including Foxo1 and Runx1, to mediate the demethylation and expression of target genes, including genes encoding repressors of TFH differentiation. Our findings establish Tet2 as an important regulator of TFH cell differentiation and reveal pathways that could be targeted to enhance immune responses against infectious disease.- Published
- 2022
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16. GFI1 Cooperates with IKZF1/IKAROS to Activate Gene Expression in T-cell Acute Lymphoblastic Leukemia.
- Author
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Sun W, Guo J, McClellan D, Poeschla A, Bareyan D, Casey MJ, Cairns BR, Tantin D, and Engel ME
- Subjects
- Humans, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Gene Expression Regulation, Leukemic, Ikaros Transcription Factor genetics, Ikaros Transcription Factor metabolism, Precursor T-Cell Lymphoblastic Leukemia-Lymphoma, Transcription Factors genetics, Transcription Factors metabolism
- Abstract
Growth factor independence-1 (GFI1) is a transcriptional repressor and master regulator of normal and malignant hematopoiesis. Repression by GFI1 is attributable to recruitment of LSD1-containing protein complexes via its SNAG domain. However, the full complement of GFI1 partners in transcriptional control is not known. We show that in T-acute lymphoblastic leukemia (ALL) cells, GFI1 and IKAROS are transcriptional partners that co-occupy regulatory regions of hallmark T-cell development genes. Transcriptional profiling reveals a subset of genes directly transactivated through the GFI1-IKAROS partnership. Among these is NOTCH3, a key factor in T-ALL pathogenesis. Surprisingly, NOTCH3 expression by GFI1 and IKAROS requires the GFI1 SNAG domain but occurs independent of SNAG-LSD1 binding. GFI1 variants deficient in LSD1 binding fail to activate NOTCH3, but conversely, small molecules that disrupt the SNAG-LSD1 interaction while leaving the SNAG primary structure intact stimulate NOTCH3 expression. These results identify a noncanonical transcriptional control mechanism in T-ALL which supports GFI1-mediated transactivation in partnership with IKAROS and suggest competition between LSD1-containing repressive complexes and others favoring transactivation., Implications: Combinatorial diversity and cooperation between DNA binding proteins and complexes assembled by them can direct context-dependent transcriptional outputs to control cell fate and may offer new insights for therapeutic targeting in cancer., (©2022 American Association for Cancer Research.)
- Published
- 2022
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17. ABCB10 Loss Reduces CD4 + T Cell Activation and Memory Formation.
- Author
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Sun W, Jia X, Liesa M, Tantin D, and Ward DM
- Subjects
- Animals, CD4-Positive T-Lymphocytes cytology, CD8-Positive T-Lymphocytes cytology, CD8-Positive T-Lymphocytes immunology, CRISPR-Cas Systems genetics, Cell Line, Cytokines immunology, Glycolysis physiology, Humans, Immunologic Memory genetics, Jurkat Cells, Lymphocyte Activation genetics, Lymphocyte Activation immunology, Mice, Mice, Inbred C57BL, Mice, Knockout, ATP-Binding Cassette Transporters genetics, CD4-Positive T-Lymphocytes immunology, Cytokines biosynthesis, Immunologic Memory immunology
- Abstract
T cells must shift their metabolism to respond to infections and tumors and to undergo memory formation. The ATP-binding cassette transporter ABCB10 localizes to the mitochondrial inner membrane, where it is thought to export a substrate important in heme biosynthesis and metabolism, but its role in T cell development and activation is unknown. In this article, we use a combination of methods to study the effect of ABCB10 loss in primary and malignantly transformed T cells. Although Abcb10 is dispensable for development of both CD4
+ and CD8+ T cells, it is required for expression of specific cytokines in CD4+ , but not CD8+ , T cells activated in vitro. These defects in cytokine expression are magnified on repeated stimulation. In vivo, CD8+ cells lacking ABCB10 expand more in response to viral infection than their control counterparts, while CD4+ cells show reductions in both number and percentage. CD4+ cells lacking ABCB10 show impairment in Ag-specific memory formation and recall responses that become more severe with time. In malignant human CD4+ Jurkat T cells, we find that CRISPR-mediated ABCB10 disruption recapitulates the same cytokine expression defects upon activation as observed in primary mouse T cells. Mechanistically, ABCB10 deletion in Jurkat T cells disrupts the ability to switch to aerobic glycolysis upon activation. Cumulatively, these results show that ABCB10 is selectively required for specific cytokine responses and memory formation in CD4+ T cells, suggesting that targeting this molecule could be used to mitigate aberrant T cell activation., (Copyright © 2022 by The American Association of Immunologists, Inc.)- Published
- 2022
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18. Targeting transcriptional coregulator OCA-B/Pou2af1 blocks activated autoreactive T cells in the pancreas and type 1 diabetes.
- Author
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Kim H, Perovanovic J, Shakya A, Shen Z, German CN, Ibarra A, Jafek JL, Lin NP, Evavold BD, Chou DH, Jensen PE, He X, and Tantin D
- Subjects
- Alleles, Amino Acid Sequence, Animals, Autoantigens immunology, CD4-Positive T-Lymphocytes immunology, CD8-Positive T-Lymphocytes immunology, Crosses, Genetic, Cytokines metabolism, Diabetes Mellitus, Type 1 prevention & control, Disease Models, Animal, Female, Gene Deletion, Germ Cells metabolism, Humans, Inflammation Mediators metabolism, Lymph Nodes metabolism, Lymphocyte Activation, Male, Mice, Inbred C57BL, Mice, Inbred NOD, Ovalbumin, Pancreas metabolism, Peptides pharmacology, Receptors, Antigen, T-Cell metabolism, Spleen pathology, Trans-Activators deficiency, Mice, Diabetes Mellitus, Type 1 genetics, Diabetes Mellitus, Type 1 immunology, Pancreas pathology, T-Lymphocytes immunology, Trans-Activators metabolism, Transcription, Genetic
- Abstract
The transcriptional coregulator OCA-B promotes expression of T cell target genes in cases of repeated antigen exposure, a necessary feature of autoimmunity. We hypothesized that T cell-specific OCA-B deletion and pharmacologic OCA-B inhibition would protect mice from autoimmune diabetes. We developed an Ocab conditional allele and backcrossed it onto a diabetes-prone NOD/ShiLtJ strain background. T cell-specific OCA-B loss protected mice from spontaneous disease. Protection was associated with large reductions in islet CD8+ T cell receptor specificities associated with diabetes pathogenesis. CD4+ clones associated with diabetes were present but associated with anergic phenotypes. The protective effect of OCA-B loss was recapitulated using autoantigen-specific NY8.3 mice but diminished in monoclonal models specific to artificial or neoantigens. Rationally designed membrane-penetrating OCA-B peptide inhibitors normalized glucose levels and reduced T cell infiltration and proinflammatory cytokine expression in newly diabetic NOD mice. Together, the results indicate that OCA-B is a potent autoimmune regulator and a promising target for pharmacologic inhibition., Competing Interests: Disclosures: D. Tantin reported a patent (62/666,325). No other disclosures were reported., (© 2020 Kim et al.)
- Published
- 2021
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19. Regulation of Tumor Initiation by the Mitochondrial Pyruvate Carrier.
- Author
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Bensard CL, Wisidagama DR, Olson KA, Berg JA, Krah NM, Schell JC, Nowinski SM, Fogarty S, Bott AJ, Wei P, Dove KK, Tanner JM, Panic V, Cluntun A, Lettlova S, Earl CS, Namnath DF, Vázquez-Arreguín K, Villanueva CJ, Tantin D, Murtaugh LC, Evason KJ, Ducker GS, Thummel CS, and Rutter J
- Subjects
- Animals, Cell Transformation, Neoplastic metabolism, Drosophila, Female, Male, Mice, Mice, Inbred C57BL, Adenoma metabolism, Carcinogenesis metabolism, Colorectal Neoplasms metabolism, Mitochondria metabolism, Mitochondrial Membrane Transport Proteins metabolism, Pyruvic Acid metabolism
- Abstract
Although metabolic adaptations have been demonstrated to be essential for tumor cell proliferation, the metabolic underpinnings of tumor initiation are poorly understood. We found that the earliest stages of colorectal cancer (CRC) initiation are marked by a glycolytic metabolic signature, including downregulation of the mitochondrial pyruvate carrier (MPC), which couples glycolysis and glucose oxidation through mitochondrial pyruvate import. Genetic studies in Drosophila suggest that this downregulation is required because hyperplasia caused by loss of the Apc or Notch tumor suppressors in intestinal stem cells can be completely blocked by MPC overexpression. Moreover, in two distinct CRC mouse models, loss of Mpc1 prior to a tumorigenic stimulus doubled the frequency of adenoma formation and produced higher grade tumors. MPC loss was associated with a glycolytic metabolic phenotype and increased expression of stem cell markers. These data suggest that changes in cellular pyruvate metabolism are necessary and sufficient to promote cancer initiation., Competing Interests: Declaration of Interests The University of Utah has filed a patent related to the mitochondrial pyruvate carrier, of which J.R. and C.S.T. are listed as co-inventors. All other authors declare no competing interests., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2020
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20. Transcriptional regulatory model of fibrosis progression in the human lung.
- Author
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McDonough JE, Ahangari F, Li Q, Jain S, Verleden SE, Herazo-Maya J, Vukmirovic M, DeIuliis G, Tzouvelekis A, Tanabe N, Chu F, Yan X, Verschakelen J, Homer RJ, Manatakis DV, Zhang J, Ding J, Maes K, De Sadeleer L, Vos R, Neyrinck A, Benos PV, Bar-Joseph Z, Tantin D, Hogg JC, Vanaudenaerde BM, Wuyts WA, and Kaminski N
- Subjects
- Aged, Animals, Disease Progression, Humans, Male, Mice, Knockout, MicroRNAs genetics, MicroRNAs metabolism, Middle Aged, Models, Biological, Trans-Activators genetics, Trans-Activators metabolism, X-Ray Microtomography, Gene Expression Regulation genetics, Idiopathic Pulmonary Fibrosis diagnostic imaging, Idiopathic Pulmonary Fibrosis genetics, Idiopathic Pulmonary Fibrosis metabolism, Idiopathic Pulmonary Fibrosis pathology, Lung diagnostic imaging, Lung metabolism, Lung pathology, Transcriptome genetics
- Abstract
To develop a systems biology model of fibrosis progression within the human lung we performed RNA sequencing and microRNA analysis on 95 samples obtained from 10 idiopathic pulmonary fibrosis (IPF) and 6 control lungs. Extent of fibrosis in each sample was assessed by microCT-measured alveolar surface density (ASD) and confirmed by histology. Regulatory gene expression networks were identified using linear mixed-effect models and dynamic regulatory events miner (DREM). Differential gene expression analysis identified a core set of genes increased or decreased before fibrosis was histologically evident that continued to change with advanced fibrosis. DREM generated a systems biology model (www.sb.cs.cmu.edu/IPFReg) that identified progressively divergent gene expression tracks with microRNAs and transcription factors that specifically regulate mild or advanced fibrosis. We confirmed model predictions by demonstrating that expression of POU2AF1, previously unassociated with lung fibrosis but proposed by the model as regulator, is increased in B lymphocytes in IPF lungs and that POU2AF1-knockout mice were protected from bleomycin-induced lung fibrosis. Our results reveal distinct regulation of gene expression changes in IPF tissue that remained structurally normal compared with moderate or advanced fibrosis and suggest distinct regulatory mechanisms for each stage.
- Published
- 2019
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21. Transcription factor Oct1 protects against hematopoietic stress and promotes acute myeloid leukemia.
- Author
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Jafek JL, Shakya A, Tai PY, Ibarra A, Kim H, Maddox J, Chumley J, Spangrude GJ, Miles RR, Kelley TW, and Tantin D
- Subjects
- Animals, Bone Marrow pathology, Bone Marrow Failure Disorders etiology, Bone Marrow Failure Disorders genetics, CDX2 Transcription Factor biosynthesis, CDX2 Transcription Factor genetics, Cell Transformation, Neoplastic genetics, CpG Islands, DNA Methylation, Disease Progression, Fluorouracil toxicity, Gene Expression Regulation, Leukemic, Hematopoietic Stem Cells drug effects, Humans, Jumonji Domain-Containing Histone Demethylases metabolism, Leukemia, Experimental genetics, Leukemia, Experimental prevention & control, Leukemia, Myeloid, Acute metabolism, Mi-2 Nucleosome Remodeling and Deacetylase Complex metabolism, Mice, Inbred C57BL, Octamer Transcription Factor-1 deficiency, Oncogene Proteins, Fusion physiology, Promoter Regions, Genetic, Radiation Chimera, Leukemia, Myeloid, Acute genetics, Neoplasm Proteins physiology, Octamer Transcription Factor-1 physiology
- Abstract
A better understanding of the development and progression of acute myelogenous leukemia (AML) is necessary to improve patient outcome. Here we define roles for the transcription factor Oct1/Pou2f1 in AML and normal hematopoiesis. Inappropriate reactivation of the CDX2 gene is widely observed in leukemia patients and in leukemia mouse models. We show that Oct1 associates with the CDX2 promoter in both normal and AML primary patient samples, but recruits the histone demethylase Jmjd1a/Kdm3a to remove the repressive H3K9me2 mark only in malignant specimens. The CpG DNA immediately adjacent to the Oct1 binding site within the CDX2 promoter exhibits variable DNA methylation in healthy control blood and bone marrow samples, but complete demethylation in AML samples. In MLL-AF9-driven mouse models, partial loss of Oct1 protects from myeloid leukemia. Complete Oct1 loss completely suppresses leukemia but results in lethality from bone marrow failure. Loss of Oct1 in normal hematopoietic transplants results in superficially normal long-term reconstitution; however, animals become acutely sensitive to 5-fluorouracil, indicating that Oct1 is dispensable for normal hematopoiesis but protects blood progenitor cells against external chemotoxic stress. These findings elucidate a novel and important role for Oct1 in AML., (Copyright © 2019 ISEH -- Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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22. T cell-selective deletion of Oct1 protects animals from autoimmune neuroinflammation while maintaining neurotropic pathogen response.
- Author
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Kim H, Dickey L, Stone C, Jafek JL, Lane TE, and Tantin D
- Subjects
- Amino Acid Sequence, Animals, CD4-Positive T-Lymphocytes immunology, Encephalomyelitis, Autoimmune, Experimental genetics, Encephalomyelitis, Autoimmune, Experimental immunology, Inflammation genetics, Inflammation immunology, Inflammation metabolism, Inflammation Mediators immunology, Mice, Mice, Inbred C57BL, Mice, Transgenic, Nerve Growth Factors genetics, Nerve Growth Factors immunology, Octamer Transcription Factor-1 genetics, Octamer Transcription Factor-1 immunology, Autoimmunity physiology, CD4-Positive T-Lymphocytes metabolism, Encephalomyelitis, Autoimmune, Experimental metabolism, Inflammation Mediators metabolism, Nerve Growth Factors metabolism, Octamer Transcription Factor-1 deficiency
- Abstract
Background: Treatments for autoimmune diseases aim to dampen autoreactivity while preserving normal immune function. In CD4
+ T cells, the transcription factor Oct1/Pou2f1 is a dispensable transcription factor for T cell development and response to primary infection, but promotes expression of target genes, including Il2 and Ifng, under conditions of antigen reencounter. As a result, they are more strongly expressed upon secondary stimulation. Such repeated antigen encounters occur in memory recall responses, in autoimmunity where self-antigen can be recognized multiple times, and in chronic infection where foreign antigen is persistent. Based on these previous findings, we hypothesized that Oct1 loss would protect animals from autoimmunity but maintain normal responses to pathogens in the CNS., Objective: We used a conditional mouse Oct1 (Pou2f1) allele and a CD4-Cre driver to determine the effect of T cell-specific Oct1 loss on autoimmune- and viral-induced neuroinflammation using an autoantigen-driven EAE model of autoimmunity and a JHMV model of viral infection., Results: Oct1 conditional deletion mitigated clinical scores and reduced infiltrating T cells and cytokine production in the EAE model. Consistently, Oct1-deficient CD4+ T cells stimulated in vitro showed increased expression of markers associated with T cell anergy, particularly in the absence of co-stimulatory signals. In contrast, anti-viral T cell effector functions are intact in the absence of Oct1, with no changes in neuroinflammation, infiltrating T cells or cytokine production., Conclusion: Our findings uncover a significant difference between the effect of Oct1 loss on autoimmune and anti-pathogen responses, which potentially could be exploited for therapeutic benefit.- Published
- 2019
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23. Oct1/Pou2f1 is selectively required for colon regeneration and regulates colon malignancy.
- Author
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Vázquez-Arreguín K, Bensard C, Schell JC, Swanson E, Chen X, Rutter J, and Tantin D
- Subjects
- Animals, Azoxymethane administration & dosage, Carcinogenesis metabolism, Carcinogenesis pathology, Colon drug effects, Colon pathology, Colonic Neoplasms chemically induced, Colonic Neoplasms mortality, Colonic Neoplasms pathology, Dextran Sulfate administration & dosage, Disease Models, Animal, Female, Gene Expression Profiling, HCT116 Cells, Humans, Integrases genetics, Integrases metabolism, Intestine, Small drug effects, Intestine, Small metabolism, Intestine, Small pathology, Mice, Mice, Knockout, Neoplastic Stem Cells drug effects, Neoplastic Stem Cells metabolism, Neoplastic Stem Cells pathology, Octamer Transcription Factor-1 deficiency, Organoids drug effects, Organoids metabolism, Organoids pathology, Receptors, G-Protein-Coupled genetics, Receptors, G-Protein-Coupled metabolism, Regeneration, Signal Transduction, Survival Analysis, Tamoxifen administration & dosage, Carcinogenesis genetics, Colon metabolism, Colonic Neoplasms genetics, Gene Expression Regulation, Neoplastic, Octamer Transcription Factor-1 genetics
- Abstract
The transcription factor Oct1/Pou2f1 promotes poised gene expression states, mitotic stability, glycolytic metabolism and other characteristics of stem cell potency. To determine the effect of Oct1 loss on stem cell maintenance and malignancy, we deleted Oct1 in two different mouse gut stem cell compartments. Oct1 deletion preserved homeostasis in vivo and the ability to establish organoids in vitro, but blocked the ability to recover from treatment with dextran sodium sulfate, and the ability to maintain organoids after passage. In a chemical model of colon cancer, loss of Oct1 in the colon severely restricted tumorigenicity. In contrast, loss of one or both Oct1 alleles progressively increased tumor burden in a colon cancer model driven by loss-of-heterozygosity of the tumor suppressor gene Apc. The different outcomes are consistent with prior findings that Oct1 promotes mitotic stability, and consistent with differentially expressed genes between the two models. Oct1 ChIPseq using HCT116 colon carcinoma cells identifies target genes associated with mitotic stability, metabolism, stress response and malignancy. This set of gene targets overlaps significantly with genes differentially expressed in the two tumor models. These results reveal that Oct1 is selectively required for recovery after colon damage, and that Oct1 has potent effects in colon malignancy, with outcome (pro-oncogenic or tumor suppressive) dictated by tumor etiology., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2019
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24. FACT Inhibition Blocks Induction But Not Maintenance of Pluripotency.
- Author
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Shen Z, Formosa T, and Tantin D
- Subjects
- 3T3 Cells, Animals, Cells, Cultured, Chromatin metabolism, Mice, Transcription Factors antagonists & inhibitors, Transcription Factors genetics, Cellular Reprogramming, Pluripotent Stem Cells cytology, Transcription Factors metabolism
- Abstract
The histone chaperone facilitates chromatin transactions (FACT) is associated with nuclear processes, including DNA transcription, replication, and repair. We previously showed that FACT is transiently recruited to pluripotency-associated target genes by newly bound Oct4. In this study, we tested the effects of FACT depletion by knockout or chemical inhibition on the induction and maintenance of pluripotency. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated deletion of the FACT subunit Spt16 did not affect the viability or proliferation of fibroblasts but blocked their ability to form induced pluripotent stem cells. Similarly, a small molecule inhibitor of FACT blocked the induction of pluripotency at an early step in reprogramming, without affecting the viability, proliferation, undifferentiated state, or the expression of core pluripotency genes. Notably, trypsinization and passage of pluripotent cells transiently reintroduced a requirement for FACT. Although FACT has been considered to be an essential transcription elongation factor, these results contribute to the emerging view that it instead promotes transitions between stable chromatin states, including during reprogramming to pluripotency.
- Published
- 2018
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25. BRCA1 through Its E3 Ligase Activity Regulates the Transcription Factor Oct1 and Carbohydrate Metabolism.
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Vázquez-Arreguín K, Maddox J, Kang J, Park D, Cano RR, Factor RE, Ludwig T, and Tantin D
- Subjects
- Animals, BRCA1 Protein genetics, Carbohydrate Metabolism, Cell Line, Tumor, Female, Heterografts, Humans, MCF-7 Cells, Metabolomics methods, Mice, Mice, Inbred NOD, Mice, SCID, BRCA1 Protein metabolism, Octamer Transcription Factor-1 metabolism, Ubiquitin-Protein Ligases metabolism
- Abstract
The tumor suppressor BRCA1 regulates the DNA damage response (DDR) and other processes that remain incompletely defined. Among these, BRCA1 heterodimerizes with BARD1 to ubiquitylate targets via its N-terminal E3 ligase activity. Here, it is demonstrated that BRCA1 promotes oxidative metabolism by degrading Oct1 (POU2F1), a transcription factor with proglycolytic and tumorigenic effects. BRCA1 E3 ubiquitin ligase mutation skews cells toward a glycolytic metabolic profile while elevating Oct1 protein. CRISPR-mediated Oct1 deletion reverts the glycolytic phenotype. RNA sequencing (RNAseq) confirms deregulation of metabolic genes downstream of Oct1. BRCA1 mediates Oct1 ubiquitylation and degradation, and mutation of two ubiquitylated Oct1 lysines insulates the protein against BRCA1-mediated destabilization. Oct1 deletion in MCF-7 breast cancer cells does not perturb growth in standard culture, but inhibits growth in soft agar and xenograft assays. In primary breast cancer clinical specimens, Oct1 protein levels correlate positively with tumor aggressiveness and inversely with BRCA1. These results identify BRCA1 as an Oct1 ubiquitin ligase that catalyzes Oct1 degradation to promote oxidative metabolism and restrict tumorigenicity. Mol Cancer Res; 16(3); 439-52. ©2018 AACR ., (©2018 American Association for Cancer Research.)
- Published
- 2018
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26. Enforcement of developmental lineage specificity by transcription factor Oct1.
- Author
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Shen Z, Kang J, Shakya A, Tabaka M, Jarboe EA, Regev A, and Tantin D
- Subjects
- Animals, Mice, Octamer Transcription Factor-3 metabolism, Cell Differentiation, Gene Expression Regulation, Developmental, Mouse Embryonic Stem Cells physiology, Octamer Transcription Factor-1 metabolism, Transcription, Genetic
- Abstract
Embryonic stem cells co-express Oct4 and Oct1, a related protein with similar DNA-binding specificity. To study the role of Oct1 in ESC pluripotency and transcriptional control, we constructed germline and inducible-conditional Oct1-deficient ESC lines. ESCs lacking Oct1 show normal appearance, self-renewal and growth but manifest defects upon differentiation. They fail to form beating cardiomyocytes, generate neurons poorly, form small, poorly differentiated teratomas, and cannot generate chimeric mice. Upon RA-mediated differentiation, Oct1-deficient cells induce lineage-appropriate developmentally poised genes poorly while lineage-inappropriate genes, including extra-embryonic genes, are aberrantly expressed. In ESCs, Oct1 co-occupies a specific set of targets with Oct4, but does not occupy differentially expressed developmental targets. Instead, Oct1 occupies these targets as cells differentiate and Oct4 declines. These results identify a dynamic interplay between Oct1 and Oct4, in particular during the critical window immediately after loss of pluripotency when cells make the earliest developmental fate decisions.
- Published
- 2017
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27. Pask integrates hormonal signaling with histone modification via Wdr5 phosphorylation to drive myogenesis.
- Author
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Kikani CK, Wu X, Paul L, Sabic H, Shen Z, Shakya A, Keefe A, Villanueva C, Kardon G, Graves B, Tantin D, and Rutter J
- Subjects
- Animals, Cell Differentiation, Cell Line, Gene Expression Regulation, Gene Knockdown Techniques, HEK293 Cells, Histone-Lysine N-Methyltransferase genetics, Humans, Intracellular Signaling Peptides and Proteins, Mice, Mouse Embryonic Stem Cells metabolism, Muscle Cells physiology, Muscle, Skeletal, Muscles injuries, MyoD Protein metabolism, Myoblasts pathology, Myogenin genetics, Myogenin metabolism, Phosphorylation, Promoter Regions, Genetic, Protein Serine-Threonine Kinases genetics, Stem Cells, Transcriptional Activation, Histone Code, Histone-Lysine N-Methyltransferase metabolism, Muscle Development physiology, Muscles metabolism, Protein Serine-Threonine Kinases metabolism, Signal Transduction
- Abstract
PAS domain containing protein kinase (Pask) is an evolutionarily conserved protein kinase implicated in energy homeostasis and metabolic regulation across eukaryotic species. We now describe an unexpected role of Pask in promoting the differentiation of myogenic progenitor cells, embryonic stem cells and adipogenic progenitor cells. This function of Pask is dependent upon its ability to phosphorylate Wdr5, a member of several protein complexes including those that catalyze histone H3 Lysine 4 trimethylation (H3K4me3) during transcriptional activation. Our findings suggest that, during myoblast differentiation, Pask stimulates the conversion of repressive H3K4me1 to activating H3K4me3 marks on the promoter of the differentiation gene myogenin ( Myog ) via Wdr5 phosphorylation. This enhances accessibility of the MyoD transcription factor and enables transcriptional activation of the Myog promoter to initiate muscle differentiation. Thus, as an upstream kinase of Wdr5, Pask integrates signaling cues with the transcriptional network to regulate the differentiation of progenitor cells., Competing Interests: The authors declare that no competing interests exist.
- Published
- 2016
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28. Good times for Oct proteins.
- Author
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Tantin D
- Subjects
- Animals, Gene Expression Regulation, Developmental, Humans, Octamer Transcription Factors metabolism, Gene Expression Regulation, Neoplastic, Octamer Transcription Factors genetics
- Published
- 2016
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29. The Oct1 transcription factor and epithelial malignancies: Old protein learns new tricks.
- Author
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Vázquez-Arreguín K and Tantin D
- Subjects
- Amino Acid Sequence, Binding Sites, Carcinogenesis metabolism, Carcinogenesis pathology, Histones genetics, Histones metabolism, Humans, Jumonji Domain-Containing Histone Demethylases genetics, Jumonji Domain-Containing Histone Demethylases metabolism, Mi-2 Nucleosome Remodeling and Deacetylase Complex genetics, Mi-2 Nucleosome Remodeling and Deacetylase Complex metabolism, Molecular Sequence Data, Neoplasms, Glandular and Epithelial metabolism, Neoplasms, Glandular and Epithelial pathology, Octamer Transcription Factor-1 metabolism, Protein Binding, Protein Structure, Tertiary, Signal Transduction, Carcinogenesis genetics, Gene Expression Regulation, Neoplastic, Neoplasms, Glandular and Epithelial genetics, Octamer Transcription Factor-1 genetics
- Abstract
The metazoan-specific POU domain transcription factor family comprises activities underpinning developmental processes such as embryonic pluripotency and neuronal specification. Some POU family proteins efficiently bind an 8-bp DNA element known as the octamer motif. These proteins are known as Oct transcription factors. Oct1/POU2F1 is the only widely expressed POU factor. Unlike other POU factors it controls no specific developmental or organ system. Oct1 was originally described to operate at target genes associated with proliferation and immune modulation, but more recent results additionally identify targets associated with oxidative and cytotoxic stress resistance, metabolic regulation, stem cell function and other unexpected processes. Oct1 is pro-oncogenic in multiple contexts, and several recent reports provide broad evidence that Oct1 has prognostic and therapeutic value in multiple epithelial tumor settings. This review focuses on established and emerging roles of Oct1 in epithelial tumors, with an emphasis on mechanisms of transcription regulation by Oct1 that may underpin these findings. This article is part of a Special Issue entitled: The Oct Transcription Factor Family, edited by Dr. Dean Tantin., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2016
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30. Oct1 and OCA-B are selectively required for CD4 memory T cell function.
- Author
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Shakya A, Goren A, Shalek A, German CN, Snook J, Kuchroo VK, Yosef N, Chan RC, Regev A, Williams MA, and Tantin D
- Subjects
- Animals, Blotting, Western, CD4-Positive T-Lymphocytes metabolism, Cells, Cultured, Gene Expression immunology, Host-Pathogen Interactions immunology, Immunologic Memory genetics, Interferon-gamma immunology, Interferon-gamma metabolism, Interleukin-2 immunology, Interleukin-2 metabolism, Jumonji Domain-Containing Histone Demethylases genetics, Jumonji Domain-Containing Histone Demethylases immunology, Jumonji Domain-Containing Histone Demethylases metabolism, Lymphocytic Choriomeningitis genetics, Lymphocytic Choriomeningitis immunology, Lymphocytic Choriomeningitis virology, Lymphocytic choriomeningitis virus immunology, Lymphocytic choriomeningitis virus physiology, Mice, Inbred C57BL, Mice, Knockout, Octamer Transcription Factor-1 genetics, Octamer Transcription Factor-1 metabolism, Protein Binding immunology, Repressor Proteins genetics, Repressor Proteins immunology, Repressor Proteins metabolism, Reverse Transcriptase Polymerase Chain Reaction, Trans-Activators genetics, Trans-Activators metabolism, CD4-Positive T-Lymphocytes immunology, Immunologic Memory immunology, Octamer Transcription Factor-1 immunology, Trans-Activators immunology
- Abstract
Epigenetic changes are crucial for the generation of immunological memory. Failure to generate or maintain these changes will result in poor memory responses. Similarly, augmenting or stabilizing the correct epigenetic states offers a potential method of enhancing memory. Yet the transcription factors that regulate these processes are poorly defined. We find that the transcription factor Oct1 and its cofactor OCA-B are selectively required for the in vivo generation of CD4(+) memory T cells. More importantly, the memory cells that are formed do not respond properly to antigen reencounter. In vitro, both proteins are required to maintain a poised state at the Il2 target locus in resting but previously stimulated CD4(+) T cells. OCA-B is also required for the robust reexpression of multiple other genes including Ifng. ChIPseq identifies ∼50 differentially expressed direct Oct1 and OCA-B targets. We identify an underlying mechanism involving OCA-B recruitment of the histone lysine demethylase Jmjd1a to targets such as Il2, Ifng, and Zbtb32. The findings pinpoint Oct1 and OCA-B as central mediators of CD4(+) T cell memory., (© 2015 Shakya et al.)
- Published
- 2015
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31. Pluripotency transcription factor Oct4 mediates stepwise nucleosome demethylation and depletion.
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Shakya A, Callister C, Goren A, Yosef N, Garg N, Khoddami V, Nix D, Regev A, and Tantin D
- Subjects
- Animals, Cell Differentiation genetics, Cells, Cultured, Chromatin Immunoprecipitation methods, DNA (Cytosine-5-)-Methyltransferases genetics, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Embryonic Stem Cells metabolism, Fibroblasts metabolism, Histones genetics, Histones metabolism, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Humans, Jumonji Domain-Containing Histone Demethylases genetics, Jumonji Domain-Containing Histone Demethylases metabolism, Mice, Nucleosomes genetics, Octamer Transcription Factor-3 genetics, Promoter Regions, Genetic genetics, Regulatory Sequences, Nucleic Acid genetics, DNA Methylation genetics, Nucleosomes metabolism, Octamer Transcription Factor-3 metabolism, Pluripotent Stem Cells metabolism
- Abstract
The mechanisms whereby the crucial pluripotency transcription factor Oct4 regulates target gene expression are incompletely understood. Using an assay system based on partially differentiated embryonic stem cells, we show that Oct4 opposes the accumulation of local H3K9me2 and subsequent Dnmt3a-mediated DNA methylation. Upon binding DNA, Oct4 recruits the histone lysine demethylase Jmjd1c. Chromatin immunoprecipitation (ChIP) time course experiments identify a stepwise Oct4 mechanism involving Jmjd1c recruitment and H3K9me2 demethylation, transient FACT (facilitates chromatin transactions) complex recruitment, and nucleosome depletion. Genome-wide and targeted ChIP confirms binding of newly synthesized Oct4, together with Jmjd1c and FACT, to the Pou5f1 enhancer and a small number of other Oct4 targets, including the Nanog promoter. Histone demethylation is required for both FACT recruitment and H3 depletion. Jmjd1c is required to induce endogenous Oct4 expression and fully reprogram fibroblasts to pluripotency, indicating that the assay system identifies functional Oct4 cofactors. These findings indicate that Oct4 sequentially recruits activities that catalyze histone demethylation and depletion., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)
- Published
- 2015
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32. Vitamin C promotes maturation of T-cells.
- Author
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Manning J, Mitchell B, Appadurai DA, Shakya A, Pierce LJ, Wang H, Nganga V, Swanson PC, May JM, Tantin D, and Spangrude GJ
- Subjects
- Animals, Azepines pharmacology, Cells, Cultured, Culture Media, Epigenesis, Genetic drug effects, Gene Expression drug effects, Gene Rearrangement, T-Lymphocyte drug effects, Histone Methyltransferases, Histone-Lysine N-Methyltransferase antagonists & inhibitors, Histone-Lysine N-Methyltransferase metabolism, Histones metabolism, Methylation, Mice, Mice, Inbred C57BL, Phthalimides pharmacology, Protein Processing, Post-Translational, Quinazolines pharmacology, Receptors, Antigen, T-Cell genetics, Receptors, Antigen, T-Cell metabolism, T-Lymphocytes immunology, T-Lymphocytes metabolism, Tryptophan analogs & derivatives, Tryptophan pharmacology, Ascorbic Acid pharmacology, Immunologic Factors pharmacology, T-Lymphocytes drug effects
- Abstract
Aims: Vitamin C (ascorbic acid) is thought to enhance immune function, but the mechanisms involved are obscure. We utilized an in vitro model of T-cell maturation to evaluate the role of ascorbic acid in lymphocyte development., Results: Ascorbic acid was essential for the developmental progression of mouse bone marrow-derived progenitor cells to functional T-lymphocytes in vitro and also played a role in vivo. Ascorbate-mediated enhancement of T-cell development was lymphoid cell-intrinsic and independent of T-cell receptor (TCR) rearrangement. Analysis of TCR rearrangements demonstrated that ascorbic acid enhanced the selection of functional TCRαβ after the stage of β-selection. Genes encoding the coreceptor CD8 as well as the kinase ZAP70 were upregulated by ascorbic acid. Pharmacologic inhibition of methylation marks on DNA and histones enhanced ascorbate-mediated differentiation, suggesting an epigenetic mechanism of Cd8 gene regulation via active demethylation by ascorbate-dependent Fe(2+) and 2-oxoglutarate-dependent dioxygenases., Innovation: We speculate that one aspect of gene regulation mediated by ascorbate occurs at the level of chromatin demethylation, mediated by Jumonji C (JmjC) domain enzymes that are known to be reliant upon ascorbate as a cofactor. JmjC domain enzymes are also known to regulate transcription factor activity. These two mechanisms are likely to play key roles in the modulation of immune development and function by ascorbic acid., Conclusion: Our results provide strong experimental evidence supporting a role for ascorbic acid in T-cell maturation as well as insight into the mechanism of ascorbate-mediated enhancement of immune function.
- Published
- 2013
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33. Oct transcription factors in development and stem cells: insights and mechanisms.
- Author
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Tantin D
- Subjects
- Animals, Humans, Octamer Transcription Factors chemistry, Signal Transduction, Stem Cells metabolism, Gene Expression Regulation, Developmental, Octamer Transcription Factors metabolism, Stem Cells cytology
- Abstract
The POU domain family of transcription factors regulates developmental processes ranging from specification of the early embryo to terminal differentiation. About half of these factors display substantial affinity for an 8 bp DNA site termed the octamer motif, and are hence known as Oct proteins. Oct4 (Pou5f1) is a well-known Oct factor, but there are other Oct proteins with varied and essential roles in development. This Primer outlines our current understanding of Oct proteins and the regulatory mechanisms that govern their role in developmental processes and concludes with the assertion that more investigation into their developmental functions is needed.
- Published
- 2013
- Full Text
- View/download PDF
34. Regulation of Oct1/Pou2f1 transcription activity by O-GlcNAcylation.
- Author
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Kang J, Shen Z, Lim JM, Handa H, Wells L, and Tantin D
- Subjects
- 3T3 Cells, Amino Acid Sequence, Animals, Binding Sites genetics, Cell Cycle Proteins genetics, Embryo, Mammalian cytology, Fibroblasts metabolism, Gene Expression Regulation, Green Fluorescent Proteins genetics, Green Fluorescent Proteins metabolism, HeLa Cells, Humans, Immunoblotting, Mice, Mice, Knockout, Microscopy, Fluorescence, Molecular Sequence Data, Mutation, Nuclear Proteins genetics, Promoter Regions, Genetic genetics, Protein Binding, Reverse Transcriptase Polymerase Chain Reaction, Transcription Factor Brn-3A genetics, Acetylglucosamine metabolism, Transcription Factor Brn-3A metabolism, Transcriptional Activation
- Abstract
The Oct1 transcription factor is a potent regulator of stress responses, metabolism, and tumorigenicity. Although Oct1 is regulated by phosphorylation and ubiquitination, the presence and importance of other modifications is unknown. Here we show that Oct1 is modified by O-linked β-N-acetylglucosamine (O-GlcNAc) moieties. We map two sites of O-GlcNAcylation at positions T255 and S728 within human Oct1. Under anchorage-independent overgrowth conditions, Oct1 associates 3-fold more strongly with the Gadd45a promoter and mediates transcriptional repression. Increased binding correlates with quantitative reductions in Oct1 nuclear periphery-associated puncta, and a reduced association with lamin B1. The O-GlcNAc modification sites are important for both Gadd45a repression and anchorage-independent survival. In contrast to chronic overgrowth conditions, following acute nutrient starvation Oct1 mediates Gadd45a activation. The O-GlcNAc sites are also important for Gadd45a activation under these conditions. We also, for the first time, identify specific Oct1 ubiquitination sites. The findings suggest that Oct1 integrates metabolic and stress signals via O-GlcNAc modification to regulate target gene activity.
- Published
- 2013
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35. Efficient chromatin immunoprecipitation using limiting amounts of biomass.
- Author
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Tantin D, Voth WP, and Shakya A
- Subjects
- Animals, Mice, Sample Size, T-Lymphocytes cytology, Chromatin Immunoprecipitation methods
- Abstract
Chromatin immunoprecipitation (ChIP) is a widely-used method for determining the interactions of different proteins with DNA in chromatin of living cells. Examples include sequence-specific DNA binding transcription factors, histones and their different modification states, enzymes such as RNA polymerases and ancillary factors, and DNA repair components. Despite its ubiquity, there is a lack of up-to-date, detailed methodologies for both bench preparation of material and for accurate analysis allowing quantitative metrics of interaction. Due to this lack of information, and also because, like any immunoprecipitation, conditions must be re-optimized for new sets of experimental conditions, the ChIP assay is susceptible to inaccurate or poorly quantitative results. Our protocol is ultimately derived from seminal work on transcription factor:DNA interactions(1,2) , but incorporates a number of improvements to sensitivity and reproducibility for difficult-to-obtain cell types. The protocol has been used successfully(3,4) , both using qPCR to quantify DNA enrichment, or using a semi-quantitative variant of the below protocol. This quantitative analysis of PCR-amplified material is performed computationally, and represents a limiting factor in the assay. Important controls and other considerations include the use of an isotype-matched antibody, as well as evaluation of a control region of genomic DNA, such as an intergenic region predicted not to be bound by the protein under study (or anticipated not to show changes under the experimental conditions). In addition, a standard curve of input material for every ChIP sample is used to derive absolute levels of enrichment in the experimental material. Use of standard curves helps to take into account differences between primer sets, regardless of how carefully they are designed, and also efficiency differences throughout the range of template concentrations for a single primer set. Our protocol is different from others that are available(5-8) in that we extensively cover the later, analysis phase.
- Published
- 2013
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36. Dynamic regulatory network controlling TH17 cell differentiation.
- Author
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Yosef N, Shalek AK, Gaublomme JT, Jin H, Lee Y, Awasthi A, Wu C, Karwacz K, Xiao S, Jorgolli M, Gennert D, Satija R, Shakya A, Lu DY, Trombetta JJ, Pillai MR, Ratcliffe PJ, Coleman ML, Bix M, Tantin D, Park H, Kuchroo VK, and Regev A
- Subjects
- Animals, Cells, Cultured, DNA genetics, DNA metabolism, Forkhead Transcription Factors metabolism, Gene Knockdown Techniques, Genome genetics, Interferon-gamma biosynthesis, Interleukin-2 genetics, Mice, Mice, Inbred C57BL, Nanowires, Neoplasm Proteins metabolism, Nuclear Proteins metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, Reproducibility of Results, Silicon, Th17 Cells immunology, Time Factors, Trans-Activators metabolism, Transcription Factors metabolism, Transcription, Genetic genetics, fas Receptor metabolism, Cell Differentiation genetics, Gene Regulatory Networks genetics, Th17 Cells cytology, Th17 Cells metabolism
- Abstract
Despite their importance, the molecular circuits that control the differentiation of naive T cells remain largely unknown. Recent studies that reconstructed regulatory networks in mammalian cells have focused on short-term responses and relied on perturbation-based approaches that cannot be readily applied to primary T cells. Here we combine transcriptional profiling at high temporal resolution, novel computational algorithms, and innovative nanowire-based perturbation tools to systematically derive and experimentally validate a model of the dynamic regulatory network that controls the differentiation of mouse TH17 cells, a proinflammatory T-cell subset that has been implicated in the pathogenesis of multiple autoimmune diseases. The TH17 transcriptional network consists of two self-reinforcing, but mutually antagonistic, modules, with 12 novel regulators, the coupled action of which may be essential for maintaining the balance between TH17 and other CD4(+) T-cell subsets. Our study identifies and validates 39 regulatory factors, embeds them within a comprehensive temporal network and reveals its organizational principles; it also highlights novel drug targets for controlling TH17 cell differentiation.
- Published
- 2013
- Full Text
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37. Constitutive nuclear localization of NFAT in Foxp3+ regulatory T cells independent of calcineurin activity.
- Author
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Li Q, Shakya A, Guo X, Zhang H, Tantin D, Jensen PE, and Chen X
- Subjects
- Active Transport, Cell Nucleus drug effects, Active Transport, Cell Nucleus genetics, Active Transport, Cell Nucleus immunology, Animals, Calcineurin genetics, Calcineurin metabolism, Carcinogens pharmacology, Cell Nucleus genetics, Cell Nucleus metabolism, Cell Proliferation drug effects, Forkhead Transcription Factors genetics, Forkhead Transcription Factors metabolism, Interleukin-2 genetics, Interleukin-2 immunology, Interleukin-2 metabolism, Ionomycin pharmacology, Ionophores pharmacology, Mice, Mice, Transgenic, NFATC Transcription Factors genetics, NFATC Transcription Factors metabolism, T-Lymphocytes, Regulatory cytology, T-Lymphocytes, Regulatory metabolism, Tetradecanoylphorbol Acetate pharmacology, Calcineurin immunology, Cell Nucleus immunology, Forkhead Transcription Factors immunology, Lymphocyte Activation, NFATC Transcription Factors immunology, T-Lymphocytes, Regulatory immunology
- Abstract
Foxp3 plays an essential role in conferring suppressive functionality to CD4(+)/Foxp3(+) regulatory T cells (Tregs). Although studies showed that Foxp3 has to form cooperative complexes with NFAT to bind to target genes, it remains unclear whether NFAT is available in the nucleus of primary Tregs for Foxp3 access. It is generally believed that NFAT in resting cells resides in the cytoplasm, and its nuclear translocation depends on calcineurin (CN) activation. We report that a fraction of NFAT protein constitutively localizes in the nucleus of primary Tregs, where it selectively binds to Foxp3 target genes. Treating Tregs with CN inhibitor does not induce export of NFAT from the nucleus, indicating that its nuclear translocation is independent of CN activity. Consistently, Tregs are resistant to CN inhibitors in the presence of IL-2 and continue to proliferate in response to anti-CD3 stimulation, whereas proliferation of non-Tregs is abrogated by CN inhibitors. In addition, PMA, which activates other transcription factors required for T cell activation but not NFAT, selectively induces Treg proliferation in the absence of ionomycin. TCR interaction with self-MHC class II is not required for PMA-induced Treg proliferation. Tregs expanded by PMA or in the presence of CN inhibitors maintain Treg phenotype and functionality. These findings shed light on Treg biology, paving the way for strategies to selectively activate Tregs.
- Published
- 2012
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38. Proliferation and metabolism: it's as easy as APC.
- Author
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Tantin D and Rutter J
- Abstract
Proliferating cells must generate both ATP and biosynthetic precursors for macromolecular synthesis. While proliferative signals have long been known to regulate metabolism, Garedew et al. now demonstrate that the proliferation apparatus itself, in the form of the ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), directly controls mitochondrial biogenesis, morphology, and respiratory activity., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
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39. Transcription factor Oct1 is a somatic and cancer stem cell determinant.
- Author
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Maddox J, Shakya A, South S, Shelton D, Andersen JN, Chidester S, Kang J, Gligorich KM, Jones DA, Spangrude GJ, Welm BE, and Tantin D
- Subjects
- Aldehyde Dehydrogenase genetics, Aldehyde Dehydrogenase metabolism, Biomarkers metabolism, CD24 Antigen metabolism, Colon cytology, Colon metabolism, HeLa Cells, Humans, Hyaluronan Receptors metabolism, Intestine, Small cytology, Intestine, Small metabolism, Phenotype, RNA, Messenger metabolism, Gene Expression Regulation, Neoplastic, Neoplastic Stem Cells cytology, Neoplastic Stem Cells metabolism, Organic Cation Transporter 1 genetics, Organic Cation Transporter 1 metabolism, Stem Cells cytology, Stem Cells metabolism
- Abstract
Defining master transcription factors governing somatic and cancer stem cell identity is an important goal. Here we show that the Oct4 paralog Oct1, a transcription factor implicated in stress responses, metabolic control, and poised transcription states, regulates normal and pathologic stem cell function. Oct1(HI) cells in the colon and small intestine co-express known stem cell markers. In primary malignant tissue, high Oct1 protein but not mRNA levels strongly correlate with the frequency of CD24(LO)CD44(HI) cancer-initiating cells. Reducing Oct1 expression via RNAi reduces the proportion of ALDH(HI) and dye efflux(HI) cells, and increasing Oct1 increases the proportion of ALDH(HI) cells. Normal ALDH(HI) cells harbor elevated Oct1 protein but not mRNA levels. Functionally, we show that Oct1 promotes tumor engraftment frequency and promotes hematopoietic stem cell engraftment potential in competitive and serial transplants. In addition to previously described Oct1 transcriptional targets, we identify four Oct1 targets associated with the stem cell phenotype. Cumulatively, the data indicate that Oct1 regulates normal and cancer stem cell function., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2012
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40. Combinatorial binding of transcription factors in the pluripotency control regions of the genome.
- Author
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Ferraris L, Stewart AP, Kang J, DeSimone AM, Gemberling M, Tantin D, and Fairbrother WG
- Subjects
- Animals, Binding Sites genetics, Blotting, Western, Cells, Cultured, Chromatin Immunoprecipitation, Chromosome Mapping, Electrophoresis, Polyacrylamide Gel, Gene Expression Regulation, Developmental, High-Throughput Nucleotide Sequencing, Homeodomain Proteins metabolism, Humans, Octamer Transcription Factor-1 metabolism, Octamer Transcription Factor-3 metabolism, Promoter Regions, Genetic, Protein Binding genetics, SOXB1 Transcription Factors genetics, SOXB1 Transcription Factors metabolism, Genome, Homeodomain Proteins genetics, Octamer Transcription Factor-1 genetics, Octamer Transcription Factor-3 genetics
- Abstract
The pluripotency control regions (PluCRs) are defined as genomic regions that are bound by POU5F1, SOX2, and NANOG in vivo. We utilized a high-throughput binding assay to record more than 270,000 different DNA/protein binding measurements along incrementally tiled windows of DNA within these PluCRs. This high-resolution binding map is then used to systematically define the context of POU factor binding, and reveals patterns of cooperativity and competition in the pluripotency network. The most prominent pattern is a pervasive binding competition between POU5F1 and the forkhead transcription factors. Like many transcription factors, POU5F1 is co-expressed with a paralog, POU2F1, that shares an apparently identical binding specificity. By analyzing thousands of binding measurements, we discover context effects that discriminate POU2F1 from POU5F1 binding. Proximal NANOG binding promotes POU5F1 binding, whereas nearby SOX2 binding favors POU2F1. We demonstrate by cross-species comparison and by chromatin immunoprecipitation (ChIP) that the contextual sequence determinants learned in vitro are sufficient to predict POU2F1 binding in vivo.
- Published
- 2011
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41. Oct1 is a switchable, bipotential stabilizer of repressed and inducible transcriptional states.
- Author
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Shakya A, Kang J, Chumley J, Williams MA, and Tantin D
- Subjects
- Animals, Base Sequence, CDX2 Transcription Factor, Cell Line, Tumor, Fibroblasts metabolism, Genetic Loci genetics, Homeodomain Proteins genetics, Humans, Jumonji Domain-Containing Histone Demethylases metabolism, Mi-2 Nucleosome Remodeling and Deacetylase Complex metabolism, Mice, Molecular Sequence Data, Promoter Regions, Genetic genetics, T-Lymphocytes metabolism, Tetradecanoylphorbol Acetate pharmacology, Organic Cation Transporter 1 metabolism, Transcription, Genetic drug effects
- Abstract
Little is known regarding how the Oct1 transcription factor regulates target gene expression. Using murine fibroblasts and two target genes, Polr2a and Ahcy, we show that Oct1 recruits the Jmjd1a/KDM3A lysine demethylase to catalyze the removal of the inhibitory histone H3K9 dimethyl mark and block repression. Using purified murine T cells and the Il2 target locus, and a colon cancer cell line and the Cdx2 target locus, we show that Oct1 recruits the NuRD chromatin-remodeling complex to promote a repressed state, but in a regulated manner can switch to a different capacity and mediate Jmjd1a recruitment to block repression. These findings indicate that Oct1 maintains repression through a mechanism involving NuRD and maintains poised gene expression states through an antirepression mechanism involving Jmjd1a. We propose that, rather than acting as a primary trigger of gene activation or repression, Oct1 is a switchable stabilizer of repressed and inducible states.
- Published
- 2011
- Full Text
- View/download PDF
42. Dynamic regulation of Oct1 during mitosis by phosphorylation and ubiquitination.
- Author
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Kang J, Goodman B, Zheng Y, and Tantin D
- Subjects
- Animals, HeLa Cells, Humans, Kinetochores metabolism, Lamin Type B metabolism, Mice, NIMA-Related Kinases, Octamer Transcription Factor-1 chemistry, Octamer Transcription Factor-1 deficiency, Organelles metabolism, Phosphorylation, Polyubiquitin metabolism, Protein Serine-Threonine Kinases metabolism, Protein Transport, Serine metabolism, Mitosis, Octamer Transcription Factor-1 metabolism, Ubiquitination
- Abstract
Background: Transcription factor Oct1 regulates multiple cellular processes. It is known to be phosphorylated during the cell cycle and by stress, however the upstream kinases and downstream consequences are not well understood. One of these modified forms, phosphorylated at S335, lacks the ability to bind DNA. Other modification states besides phosphorylation have not been described., Methodology/principal Findings: We show that Oct1 is phosphorylated at S335 in the Oct1 DNA binding domain during M-phase by the NIMA-related kinase Nek6. Phospho-Oct1 is also ubiquitinated. Phosphorylation excludes Oct1 from mitotic chromatin. Instead, Oct1(pS335) concentrates at centrosomes, mitotic spindle poles, kinetochores and the midbody. Oct1 siRNA knockdown diminishes the signal at these locations. Both Oct1 ablation and overexpression result in abnormal mitoses. S335 is important for the overexpression phenotype, implicating this residue in mitotic regulation. Oct1 depletion causes defects in spindle morphogenesis in Xenopus egg extracts, establishing a mitosis-specific function of Oct1. Oct1 colocalizes with lamin B1 at the spindle poles and midbody. At the midbody, both proteins are mutually required to correctly localize the other. We show that phospho-Oct1 is modified late in mitosis by non-canonical K11-linked polyubiquitin chains. Ubiquitination requires the anaphase-promoting complex, and we further show that the anaphase-promoting complex large subunit APC1 and Oct1(pS335) interact., Conclusions/significance: These findings reveal mechanistic coupling between Oct1 phosphorylation and ubquitination during mitotic progression, and a role for Oct1 in mitosis.
- Published
- 2011
- Full Text
- View/download PDF
43. Stem cells, stress, metabolism and cancer: a drama in two Octs.
- Author
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Kang J, Shakya A, and Tantin D
- Subjects
- Animals, Cell Differentiation physiology, Humans, Neoplasms genetics, Octamer Transcription Factor-1 classification, Octamer Transcription Factor-1 genetics, Octamer Transcription Factor-3 classification, Octamer Transcription Factor-3 genetics, Phylogeny, Energy Metabolism, Neoplasms metabolism, Octamer Transcription Factor-1 metabolism, Octamer Transcription Factor-3 metabolism, Stem Cells physiology, Stress, Physiological
- Abstract
It is a classic story of two related transcription factors. Oct4 is a potent regulator of pluripotency during early mammalian embryonic development, and is notable for its ability to convert adult somatic cells to pluripotency. The widely expressed Oct1 protein shares significant homology with Oct4, binds to the same sequences, regulates common target genes, and shares common modes of upstream regulation, including the ability to respond to cellular stress. Both proteins are also associated with malignancy, yet Oct1 cannot substitute for Oct4 in the generation of pluripotency. The molecular underpinnings of these phenomena are emerging, as are the consequences for adult stem cells and cancer, and thereby hangs a tale.
- Published
- 2009
- Full Text
- View/download PDF
44. Oct1 loss of function induces a coordinate metabolic shift that opposes tumorigenicity.
- Author
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Shakya A, Cooksey R, Cox JE, Wang V, McClain DA, and Tantin D
- Subjects
- Amino Acids metabolism, Animals, Embryo, Mammalian cytology, Embryo, Mammalian metabolism, Embryo, Mammalian ultrastructure, Fibroblasts metabolism, Fibroblasts ultrastructure, Gene Expression Profiling, Gene Expression Regulation, Glucose metabolism, Glycolysis, Humans, Metabolome, Mice, Mitochondria metabolism, Octamer Transcription Factor-1 metabolism, Oxidation-Reduction, Neoplasms metabolism, Neoplasms pathology, Octamer Transcription Factor-1 deficiency
- Abstract
Cancer cells frequently undergo a shift from oxidative to glycolytic metabolism. Although there is interest in targeting metabolism as a form of cancer therapy, this area still remains in its infancy. Using cells, embryos and adult animals, we show here that loss of the widely expressed transcription factor Oct1 induces a coordinated metabolic shift: mitochondrial activity and amino acid oxidation are increased, while glucose metabolism is reduced. Altered expression of direct Oct1 targets encoding metabolic regulators provides a mechanistic underpinning to these results. We show that these metabolic changes directly oppose tumorigenicity. Collectively, our findings show that Oct1, the genes it regulates and the pathways these genes affect could be used as targets for new modes of cancer therapy.
- Published
- 2009
- Full Text
- View/download PDF
45. A general mechanism for transcription regulation by Oct1 and Oct4 in response to genotoxic and oxidative stress.
- Author
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Kang J, Gemberling M, Nakamura M, Whitby FG, Handa H, Fairbrother WG, and Tantin D
- Subjects
- Amino Acid Sequence, Animals, Dimerization, HeLa Cells, Humans, Inverted Repeat Sequences genetics, Mice, Models, Molecular, Molecular Sequence Data, Mutation, Octamer Transcription Factor-1 chemistry, Octamer Transcription Factor-1 genetics, Octamer Transcription Factor-3 chemistry, Octamer Transcription Factor-3 genetics, Phosphorylation, Protein Binding, Protein Structure, Tertiary, DNA Damage physiology, Gene Expression Regulation, Octamer Transcription Factor-1 metabolism, Octamer Transcription Factor-3 metabolism, Oxidative Stress physiology
- Abstract
Oct1 and Oct4 are homologous transcription factors with similar DNA-binding specificities. Here we show that Oct1 is dynamically phosphorylated in vivo following exposure of cells to oxidative and genotoxic stress. We further show that stress regulates the selectivity of both proteins for specific DNA sequences. Mutation of conserved phosphorylation target DNA-binding domain residues in Oct1, and Oct4 confirms their role in regulating binding selectivity. Using chromatin immunoprecipitation, we show that association of Oct4 and Oct1 with a distinct group of in vivo targets is inducible by stress, and that Oct1 is essential for a normal post-stress transcriptional response. Finally, using an unbiased Oct1 target screen we identify a large number of genes targeted by Oct1 specifically under conditions of stress, and show that several of these inducible Oct1 targets are also inducibly bound by Oct4 in embryonic stem cells following stress exposure.
- Published
- 2009
- Full Text
- View/download PDF
46. High-throughput biochemical analysis of in vivo location data reveals novel distinct classes of POU5F1(Oct4)/DNA complexes.
- Author
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Tantin D, Gemberling M, Callister C, and Fairbrother WG
- Subjects
- Animals, Binding Sites, Cell Line, Chromatin Immunoprecipitation, DNA chemistry, DNA metabolism, Embryonic Stem Cells metabolism, Genomics, Humans, Mice, Oligonucleotide Probes, Promoter Regions, Genetic, Electrophoretic Mobility Shift Assay methods, Octamer Transcription Factor-3 metabolism, Oligonucleotide Array Sequence Analysis methods, Regulatory Elements, Transcriptional
- Abstract
The transcription factor POU5F1 is a key regulator of embryonic stem (ES) cell pluripotency and a known oncoprotein. We have developed a novel high-throughput binding assay called MEGAshift (microarray evaluation of genomic aptamers by shift) that we use to pinpoint the exact location, affinity, and stoichiometry of the DNA-protein complexes identified by chromatin immunoprecipitation studies. We consider all genomic regions identified as POU5F1-ChIP-enriched in both human and mouse. Compared with regions that are ChIP-enriched in a single species, we find these regions more likely to be near actively transcribed genes in ES cells. We resynthesize these genomic regions as a pool of tiled 35-mers. This oligonucleotide pool is then assayed for binding to recombinant POU5F1 by gel shift. The degree of binding for each oligonucleotide is accurately measured on a custom oligonucleotide microarray. We explore the relationship between experimentally determined and computationally predicted binding strengths, find many novel functional combinations of POU5F1 half sites, and demonstrate efficient motif discovery by incorporating binding information into a motif finding algorithm. In addition to further refining location studies for transcription factors, this method holds promise for the high-throughput screening of promoters, SNP regions, and epigenetic modifications for factor binding.
- Published
- 2008
- Full Text
- View/download PDF
47. An inducible enhancer required for Il12b promoter activity in an insulated chromatin environment.
- Author
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Zhou L, Nazarian AA, Xu J, Tantin D, Corcoran LM, and Smale ST
- Subjects
- Animals, Base Sequence, Cell Line, Deoxyribonuclease I metabolism, Interleukin-12 Subunit p40 genetics, Lipopolysaccharides pharmacology, Macrophage Activation, Mice, Molecular Sequence Data, Nucleosomes metabolism, Octamer Transcription Factor-1 metabolism, Octamer Transcription Factor-2 metabolism, Transcription Initiation Site, Chromatin metabolism, Enhancer Elements, Genetic, Interleukin-12 Subunit p40 metabolism, Macrophages metabolism, Promoter Regions, Genetic
- Abstract
Interleukin-12 (IL-12) and IL-23 are heterodimeric cytokines that serve as critical regulators of T helper cell development. The Il12b gene, which encodes the p40 subunit of both IL-12 and IL-23, is expressed in macrophages and dendritic cells following induction by bacterial products. Although the Il12b promoter, like the promoters of most proinflammatory genes, can support transcriptional induction in typical transfection assays, we show that it is not sufficient for transcription in an insulated chromatin environment. Using a DNase I hypersensitivity assay, two potential distal control regions were identified. One region, DNase I-hypersensitive site 1 (HSS1), located 10 kb upstream of the transcription start site, exhibited hypersensitivity only in stimulated macrophages. In an insulated environment, a 105-bp fragment spanning HSS1 was sufficient for transcription when combined with the Il12b promoter. Although several elements are likely to contribute to activity of the endogenous HSS1 enhancer, including an evolutionarily conserved binding site for C/EBP proteins, the only element required for activity in transient- and stable-transfection assays bound Oct-1 and Oct-2, both of which are expressed constitutively in macrophages. Oct-1 and Oct-2 were recruited to the enhancer upon macrophage stimulation, and the Oct site appeared important for nucleosome remodeling at HSS1. These results suggest that the HSS1 enhancer and Oct proteins play central roles in Il12b induction upon macrophage activation.
- Published
- 2007
- Full Text
- View/download PDF
48. Oct-1 is involved in the transcriptional repression of the p15(INK4b) gene.
- Author
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Hitomi T, Matsuzaki Y, Yasuda S, Kawanaka M, Yogosawa S, Koyama M, Tantin D, and Sakai T
- Subjects
- Cell Line, Cellular Senescence genetics, Gene Expression Regulation physiology, Humans, Transfection, Cyclin-Dependent Kinase Inhibitor p15 genetics, Octamer Transcription Factor-1 physiology, Repressor Proteins physiology, Transcription, Genetic
- Abstract
p15(INK4b) functions as a tumor suppressor and implicated in cellular senescence. Here, we show that the Oct-1 binding site in the human p15(INK4b) gene promoter functions as a silencer. Oct-1 specifically interacts with this binding site in vitro and in vivo and SMRT and HDAC1 are present in the p15(INK4b) proximal promoter region. Moreover, mouse embryo fibroblasts (MEFs) lacking Oct-1 have shown significantly increased levels of p15(INK4b) protein compared to their normal counterparts. Treatment with a histone deacetylase (HDAC) inhibitor has activated the expression of p15(INK4b) in wild-type MEFs but has no effect in MEFs lacking Oct-1, suggesting that Oct-1 represses p15(INK4b) gene expression in an HDAC-dependent manner. Finally, we show that the expression of Oct-1 protein significantly decreases, whereas p15(INK4b) protein significantly increases with the cellular aging process. Taken together, these results suggest that Oct-1 is an important transcriptional repressor for p15(INK4b) gene and the transcriptional repression of the p15(INK4b) gene by Oct-1 may be one of the regulatory mechanisms of cellular senescence.
- Published
- 2007
- Full Text
- View/download PDF
49. The octamer binding transcription factor Oct-1 is a stress sensor.
- Author
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Tantin D, Schild-Poulter C, Wang V, Haché RJ, and Sharp PA
- Subjects
- 3T3 Cells, Animals, Doxorubicin, Fibroblasts drug effects, Fibroblasts radiation effects, Gene Expression Regulation drug effects, Gene Expression Regulation radiation effects, Hydrogen Peroxide, Mice, Octamer Transcription Factor-1 deficiency, Octamer Transcription Factor-1 genetics, Oxidative Stress, Reverse Transcriptase Polymerase Chain Reaction, Gene Expression Regulation physiology, Octamer Transcription Factor-1 physiology
- Abstract
The POU-domain transcription factor Oct-1 is widely expressed in adult tissues and has been proposed to regulate a large group of target genes. Microarray expression profiling was used to evaluate gene expression changes in Oct-1-deficient mouse fibroblasts. A number of genes associated with cellular stress exhibited altered expression. Consistent with this finding, Oct-1-deficient fibroblasts were hypersensitive to gamma radiation, doxorubicin, and hydrogen peroxide and harbored elevated reactive oxygen species. Expression profiling identified a second group of genes dysregulated in Oct-1-deficient fibroblasts following irradiation, including many associated with oxidative and metabolic stress. A number of these genes contain octamer sequences in their immediate 5' regulatory regions, some of which are conserved in human. These results indicate that Oct-1 modulates the activity of genes important for the cellular response to stress.
- Published
- 2005
- Full Text
- View/download PDF
50. B cell development and immunoglobulin transcription in Oct-1-deficient mice.
- Author
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Wang VE, Tantin D, Chen J, and Sharp PA
- Subjects
- Adoptive Transfer, Animals, B-Lymphocytes immunology, Cell Division, Cell Line, Transformed, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Embryo, Mammalian embryology, Embryo, Mammalian metabolism, Gene Deletion, Genes, RAG-1 genetics, Host Cell Factor C1, Immunoglobulin Heavy Chains biosynthesis, Immunoglobulin Heavy Chains genetics, Immunoglobulin Light Chains biosynthesis, Immunoglobulin Light Chains genetics, Immunoglobulins biosynthesis, Immunoglobulins blood, Mice, Mice, Knockout, Octamer Transcription Factor-1, Phenotype, Transcription Factors genetics, Transcription Factors metabolism, B-Lymphocytes cytology, B-Lymphocytes metabolism, DNA-Binding Proteins deficiency, Gene Expression Regulation genetics, Immunoglobulins genetics, Transcription Factors deficiency, Transcription, Genetic genetics
- Abstract
The POU domain transcription factors Oct-1 and Oct-2 interact with the octamer element, a motif conserved within Ig promoters and enhancers, and mediate transcription from the Ig loci. Inactivation of Oct-2 by gene targeting results in normal B cell development and Ig transcription. To study the role of Oct-1 in these processes, the lymphoid compartment of RAG-1(-/-) animals was reconstituted with Oct-1-deficient fetal liver hematopoietic cells. Recipient mice develop B cells with levels of surface Ig expression comparable with wild type, although at slightly reduced numbers. These B cells transcribe Ig normally, respond to antigenic stimulation, undergo class switching, and use a normal repertoire of light chain variable segments. However, recipient mice show slight reductions in serum IgM and IgA. Thus, the Oct-1 protein is dispensable for B cell development and Ig transcription.
- Published
- 2004
- Full Text
- View/download PDF
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