Search

Leukemia is caused by the accumulation of multiple genomic lesions in hematopoietic precursor cells. However, how these events cooperate during oncogenic transformation remains poorly understood. We studied the cooperation between activated JAK3/STAT5 signaling and HOXA9 overexpression, two events identified as significantly co-occurring in T-cell acute lymphoblastic leukemia. Expression of mutant JAK3 and HOXA9 led to a rapid development of leukemia originating from multipotent or lymphoid-committed progenitors, with a significant decrease in disease latency compared with JAK3 or HOXA9 alone. Integrated RNA sequencing, chromatin immunoprecipitation sequencing, and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) revealed that STAT5 and HOXA9 have co-occupancy across the genome, resulting in enhanced STAT5 transcriptional activity and ectopic activation of FOS/JUN (AP1). Our data suggest that oncogenic transcription factors such as HOXA9 provide a fertile ground for specific signaling pathways to thrive, explaining why JAK/STAT pathway mutations accumulate in HOXA9-expressing cells. Significance: The mechanism of oncogene cooperation in cancer development remains poorly characterized. In this study, we model the cooperation between activated JAK/STAT signaling and ectopic HOXA9 expression during T-cell leukemia development. We identify a direct cooperation between STAT5 and HOXA9 at the transcriptional level and identify PIM1 kinase as a possible drug target in mutant JAK/STAT/HOXA9-positive leukemia cases. Cancer Discov; 8(5); 616-31. ©2018 AACR. This article is highlighted in the In This Issue feature, p. 517 ., (©2018 American Association for Cancer Research.)

Brain tumors typically arise sporadically and do not affect several family members simultaneously. In the present study, we describe clinical and genetic data from two patients, a mother and her daughter, with familial brain tumors. Exome sequencing revealed a germline missense mutation in the TP53 and ATRX genes in both cases, and a somatic copy-neutral loss of heterozygosity (LOH) in TP53 in both atypical teratoid/rhabdoid tumor (AT/RT) and astrocytoma tumors. ATRX mutation was associated with the loss of ATRX protein expression. In the astrocytoma case, R132C missense mutation was found in the known hotspot site in isocitrate dehydrogenase 1 ( IDH1 ) and LOH was detected in TP53 The mother carried few other somatic alterations, suggesting that the IDH1 mutation and LOH in TP53 were sufficient to drive tumor development. The genome in the AT/RT tumor was atypically aneuploid: Most chromosomes had experienced copy-neutral LOH or whole-chromosome gains. Only Chromosome 18 had normal diploid status. INI1/hSNF5/SMARCB1 was homozygously deleted in the AT/RT tumor. This report provides further information about tumor development in a predisposed genetic background and describes two special Li-Fraumeni cases with a familial brain tumor., (© 2018 Nordfors et al.; Published by Cold Spring Harbor Laboratory Press.)

Methodological advances that allow deeper characterization of non-coding elements in the genome have started to reveal the full spectrum of deregulation in cancer. We generated an inducible cell model to track transcriptional changes after induction of a well-known leukemia-inducing fusion gene, ETV6-RUNX1. Our data revealed widespread transcriptional alterations outside coding elements in the genome. This adds to the growing list of various alterations in the non-coding genome in cancer and pinpoints their role in diseased cellular state.

Cell signalling, which is often derailed in cancer, is a network of multiple interconnected pathways with numerous feedback mechanisms. Dynamics of cell signalling is intimately regulated by addition and removal of phosphate groups by kinases and phosphatases. We examined expression of members of the PTP4A family of phosphatases across acute leukemias. While expression of PTP4A1 and PTP4A2 remained relatively unchanged across diseases, PTP4A3 showed marked overexpression in ETV6-RUNX1 and BCR-ABL1 subtypes of precursor B cell acute lymphoblastic leukemia. We show that PTP4A3 is regulated by the ETV6-RUNX1 fusion, but noticed no marked impact on cell viability either after PTP4A3 silencing or treatment with a PTP4A3 inhibitor. Regulation of PTP4A3 expression is altered in specific subgroups of acute leukemias and this is likely brought about by expression of the aberrant fusion genes., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

High doses of ionizing radiation are an established cause of childhood leukemia. However, substantial uncertainty remains about the effect of low doses of radiation, including background radiation and potential differences between genetic subgroups of leukemia have rarely been explored. We investigated the effect of the background gamma radiation on childhood leukemia using a nationwide register-based case-control study. For each of the 1,093 cases, three age- and gender matched controls were selected (N = 3,279). Conditional logistic regression analyses were adjusted for confounding by Down syndrome, birth weight (large for gestational age), and maternal smoking. Complete residential histories and previously collected survey data of the background gamma radiation in Finland were used to assess the exposure of the study subjects to indoor and outdoor gamma radiation. Overall, background gamma radiation showed a non-significant association with the OR of childhood leukemia (OR 1.01, 95% CI 0.97, 1.05 for 10 nSv/h increase in average equivalent dose rate to red bone marrow). In subgroup analyses, age group 2-<7 years displayed a larger effect (OR 1.27, 95% CI 1.01, 1.60 for 1 mSv increase in equivalent cumulative dose to red bone marrow). Suggestive difference in OR by genetic subtype was found. Our results provide further support to the notion that low doses of ionizing radiation increase the risk for childhood leukemia, particularly at age 2-<7 years. Our findings suggest a larger effect of radiation on leukemia with high hyperpdiploidy than other subgroups, but this result requires further confirmation., (© 2016 UICC.)

Approximately 20%-25% of childhood acute lymphoblastic leukemias carry the ETV6-RUNX1 (E/R) fusion gene, a fusion of two central hematopoietic transcription factors, ETV6 (TEL) and RUNX1 (AML1). Despite its prevalence, the exact genomic targets of E/R have remained elusive. We evaluated gene loci and enhancers targeted by E/R genome-wide in precursor B acute leukemia cells using global run-on sequencing (GRO-seq). We show that expression of the E/R fusion leads to widespread repression of RUNX1 motif-containing enhancers at its target gene loci. Moreover, multiple super-enhancers from the CD19 + /CD20 + -lineage were repressed, implicating a role in impediment of lineage commitment. In effect, the expression of several genes involved in B cell signaling and adhesion was down-regulated, and the repression depended on the wild-type DNA-binding Runt domain of RUNX1. We also identified a number of E/R-regulated annotated and de novo noncoding genes. The results provide a comprehensive genome-wide mapping between E/R-regulated key regulatory elements and genes in precursor B cell leukemia that disrupt normal B lymphopoiesis., (© 2016 Teppo et al.; Published by Cold Spring Harbor Laboratory Press.)

Aim: We investigated the characteristics and outcome of paediatric patients with solid tumours diagnosed and treated at the Tampere University Hospital, one of the five tertiary referral centres in Finland, for children and adolescents with malignancies., Methods: This retrospective cohort study collected data from hospital medical records on survival, diagnosis, age, sex, tumour size and stage at diagnosis. We also observed the disease recurrence and use of autologous haematopoietic stem cell transplantation. Data analyses were carried out with the Kaplan-Meier method, various nonparametric and parametric tests, and Cox regression modelling., Results: Between 1987 and May 2015, 424 children (59% boys), with a median age of 6.4 (IQR 2.5-11.8) years at diagnosis, were diagnosed and followed up for a median of 7.5 (range 0-27.9) years. Central nervous system (CNS) tumours were the most common (38%), followed by lymphomas (19%), soft tissue sarcomas (10%), renal tumours (9%) and neuroblastomas (9%). The five-year overall survival rate of all solid tumour patients was 84% (95% CI, 81-88%), 82% (95% CI, 76-89%) for CNS and 85% (95% CI, 80-90%) for non-CNS tumours. Advanced tumour stage at diagnosis predicted a poor prognosis., Conclusion: The treatment results in our study are comparable with those previously published. A comprehensive local database allows for a timely follow-up of the characteristics and quality of treatment of childhood malignancies., (©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

Progression of malignancy to overt disease requires multiple genetic hits. Activation-induced deaminase (AID) can drive lymphomagenesis by generating off-target DNA breaks at loci that harbor highly active enhancers and display convergent transcription. The first active transcriptional profiles from acute lymphoblastic leukemia (ALL) patients acquired here reveal striking similarity at structural variation (SV) sites. Specific transcriptional features, namely convergent transcription and Pol2 stalling, were detected at breakpoints. The overlap was most prominent at SV with recognition motifs for the recombination activating genes (RAG). We present signal feature analysis to detect vulnerable regions and quantified from human cells how convergent transcription contributes to R-loop generation and RNA polymerase stalling. Wide stalling regions were characterized by high DNAse hypersensitivity and unusually broad H3K4me3 signal. Based on 1382 pre-B-ALL patients, the ETV6-RUNX1 fusion positive patients had over ten-fold elevation in RAG1 while high expression of AID marked pre-B-ALL lacking common cytogenetic changes.

Aim: In Finland, specialist paediatrics training is led by university hospitals, but half of it is carried out in regional central hospitals. We audited the training provided by four regional central hospitals in the tertiary care area covered by Tampere University Hospital, in 2003, 2008 and 2015., Methods: The audits comprised hospital visits and discussions with the chief doctor of the paediatric clinic, the trainees and the specialists who trained them. A modified version of the European Union of Medical Specialists 1997 protocol was used, and the key areas that performed poorly in the audits were followed up., Results: In 2008 and 2015, most of the key follow-up issues had improved, but two main areas in need of further development were identified in 2015. These were that educational objectives should be clarified, and their implementation systemically followed up, and that trainees should spend more time working in outpatient settings., Conclusion: Since 2003, a marked improvement had taken place in the paediatric training provided by regional central hospitals, partly because of the increase in paediatric specialist resources. This study underlines the importance of repeat audits and the need for co-opera-tion between the university hospital and regional hospitals, including regular visits., (©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

Sin3A-associated protein 30-like (SAP30L) is one of the key proteins in a multi-subunit protein complex involved in transcriptional regulation via histone deacetylation. SAP30L, together with a highly homologous SAP30 as well as other SAP proteins (i.e., SAP25, SAP45, SAP130, and SAP180), is an essential component of the Sin3A corepressor complex, although its actual role has remained elusive. SAP30L is thought to function as an important stabilizing and bridging molecule in the complex and to mediate its interactions with other corepressors. SAP30L has been previously shown to contain an N-terminal Cys3 His type zinc finger (ZnF) motif, which is responsible for the key protein-protein, protein-DNA, and protein-lipid interactions. By using high-resolution mass spectrometry, we studied a redox-dependent disulfide bond formation in SAP30L ZnF as a regulatory mechanism for its structure and function. We showed that upon oxidative stress SAP30L undergoes the formation of two specific disulfide bonds, a vicinal Cys29-Cys30 and Cys38-Cys74, with a concomitant release of the coordinated zinc ion. The oxidized protein was shown to remain folded in solution and to bind signaling phospholipids. We also determined a solution NMR structure for SAP30L ZnF that showed an overall fold similar to that of SAP30, determined earlier. The NMR titration experiments with lipids and DNA showed that the binding is mediated by the C-terminal tail as well as both α-helices of SAP30L ZnF. The implications of these results for the structure and function of SAP30L are discussed., (© 2015 The Protein Society.)

Purpose: An infective origin of childhood leukemia has been postulated, with leukemia developing as a rare response to an infection. Population mixing can result in increased contacts between infected and susceptible individuals and may increase the risk of leukemia. The objective of this study was to investigate the association between residential mobility as an indicator of population mixing at individual level and the risk of leukemia in children (<15 years)., Methods: We conducted a population-based case-control study using Finnish register data. Cases (n = 1,093) were all children diagnosed with leukemia (M9800-M9948 in ICD-O-3) at <15 years of age in Finland in 1990-2011. We chose randomly three controls per case (n = 3,279), free of cancer and alive in the end of the index year (diagnosis of the case). Controls were matched by sex and age. A comprehensive history of residential mobility was constructed from the population registry including overall migration, moving to a larger municipality (more inhabitants), and moving to a municipality with low, intermediate, or high migration intensity. The association between residential mobility and the risk of childhood leukemia was evaluated using conditional logistic regression., Results: We did not observe consistently increased or decreased risks of childhood leukemia associated with different migration patterns. Overall, residential mobility showed odds ratios nonsignificantly below unity, and no elevated risks were found., Conclusion: Our results do not indicate that higher residential mobility or moving to municipalities with more inhabitants is associated with risk of childhood leukemia.

Williams syndrome (WS) is a relatively rare multisystem neurodevelopmental disorder caused by a hemizygous deletion of contiguous genes on chromosome 7q11.23. Although WS does not predispose carriers to cancers, alterations of chromosome 7 are common in several human neoplasms. We report here a patient with WS and two different cancers, Burkitt lymphoma and Ewing sarcoma. Array-CGH analysis of the patient blood revealed a constitutive 1.4 million base pair deletion at 7q11.23, compatible with WS diagnosis., (© 2014 Wiley Periodicals, Inc.)

A quarter of cancers diagnosed in those under 18 years of age are leukemias, another quarter being tumors of the central nervous system. The remaining cancers are solid tumors occurring elswehere in the body, most commonly lymphomas, soft tissue and bone sarcomas, neuroblastomas and Wilms tumors. In almost all cases, the treatment of these solid tumors consists of combinations of surgery, cytotoxic drugs and radiotherapy. Although the prognoses have improved, they exhibit variation even within tumor groups. New targeted therapies are being developed, but for the time being they do not have any significant role.

Unlabelled: The rapid increase in information about genes and their associations with human diseases has highlighted the need for model organisms suitable for genetic manipulation and drug testing. The zebrafish is a valuable vertebrate animal model that offers many advantages, including the relative ease of husbandry and genetic manipulation and the capacity for high-throughput screens. In this review, we describe the zebrafish as a model for paediatric diseases, with particular emphasis on haematopoietic and infectious diseases., Conclusion: The zebrafish has become an established vertebrate model in which to elucidate the molecular mechanisms of various human diseases., (© 2012 The Author(s)/Acta Paediatrica © 2012 Foundation Acta Paediatrica.)

Purpose: Small nucleolar RNAs (snoRNAs) direct sequence-specific modifications to ribosomal RNA. We hypothesized that the expression of snoRNAs may be altered in leukemic cells., Methods: The expression of snoRNAs was analyzed in various leukemic cell lines by massive parallel sequencing (SOLiD). Quantitative real-time PCR (RT-qPCR) was used to validate the expression profiles., Results: Our results show characteristic differences in the expression patterns of snoRNAs between cell lines representing the main subgroups of leukemia, AML, pre-B-ALL and T-ALL, respectively. In RT-qPCR analyses, several snoRNAs were found to be differentially expressed in T-ALL as compared to pre-B-ALL cell lines., Conclusions: snoRNAs are differentially expressed in various leukemic cell lines and could, therefore, be potentially useful in the classification of leukemia subgroups.

Most cases of childhood leukemia are acute lymphoblastic leukemia, a small proportion being myelogenous leukemia. Chronic myelogenous leukemia is rare in children, whereas chronic lymphocytic leukemia is not encountered. The prognosis of childhood leukemia has improved considerably so that approximately 80 to 90% of those having lymphocytic leukemia and 60 to 70% of those having myelogenous leukemia will recover fully. The challenge is to develop new treatments for disease groups having a poor prognosis and on the other hand to lighten the treatments for leukemias having a good prognosis.

Brain tumors are the second most common pediatric neoplastic disease after leukemias. As causes of mortality and morbidity they add up to the most significant group of tumors. Treatment is based on thorough surgical excision of the tumor. Additional treatment with cytotoxic agents and radiotherapy is applied to malignant tumors. Treatment results have improved so that approximately three children out of four will make complete recovery from brain tumor. Long-term problems are, however, common and often significantly weakening the quality of life.

The Sin3A-associated proteins SAP30 and SAP30L share 70% sequence identity and are part of the multiprotein Sin3A corepressor complex. They participate in gene repression events by linking members of the complex and stabilizing interactions among the protein members as well as between proteins and DNA. While most organisms have both SAP30 and SAP30L, the zebrafish is exceptional because it only has SAP30L. Here we demonstrate that SAP30L is expressed ubiquitously in embryonic and adult zebrafish tissues. Knockdown of SAP30L using morpholino-mediated technology resulted in a morphant phenotype manifesting as cardiac insufficiency and defective hemoglobinization of red blood cells. A microarray analysis of gene expression in SAP30L morphant embryos revealed changes in the expression of genes involved in regulation of transcription, TGF-beta signaling, Wnt-family transcription factors, and nuclear genes encoding mitochondrial proteins. The expression of the heart-specific nkx2.5 gene was markedly down-regulated in SAP30L morphants, and the cardiac phenotype could be partially rescued by nkx2.5 mRNA. In addition, changes were detected in the expression of genes known to be important in hemoglobin synthesis and erythropoiesis. Our results demonstrate that SAP30L regulates several transcriptional pathways in zebrafish embryos and is involved in the development of cardiac and hematopoietic systems., (Copyright © 2012 Wiley Periodicals, Inc.)

The zebrafish has proven to be a valuable vertebrate model in which to elucidate the molecular mechanisms of various diseases. A high degree of genetic and morphological similarity in hematopoiesis between the zebrafish and human indicates that zebrafish can provide valuable knowledge about the mechanisms behind pathogenesis of leukemia. To date, a small number of zebrafish leukemia models have been published and they have already provided some interesting information. However, the full potential of these models, especially the identification of contributing genetic factors and high-throughput drug screens, is yet to be fulfilled. Further transgenic or mutant animals are needed, especially for modeling high-risk leukemias, such as MLL rearranged infant leukemias., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Congenital fibrosarcomas are malignant tumors that arise in soft tissues. In infants this unique tumor does not commonly metastasize, even though there may be local recurrences. We report here a boy who had congenital fibrosarcoma in his right foot, which was completely excised at the age of 3 days. Four months later, a solitary encapsulated metastasis emerged in thoracic chest wall, which was operated. During adjuvant chemotherapy he developed histologically confirmed fibrosarcoma metastases in the heart. After extended treatment with cyclophosphamide/topotecan and gemcitabine/docetaxel, the heart tumors disappeared and he has been in complete remission for 3 years.

The molecular function of phospholipids in the nucleus has been only partially elucidated. The upsurge of epigenetic research has contributed to increased interest in nuclear phospholipids, such as phosphoinositides, and their involvement in gene transcription. However, the mechanisms by which phosphoinositides regulate transcription is still unknown at the molecular level. Certain phosphoinositide species can regulate protein-chromatin and protein-nucleic acid interactions, and specific nuclear target proteins link nuclear signaling lipids to gene expression. We propose that a phosphoinositide-mediated detachment of proteins from chromatin is a general biological mechanism that partly underlies the signaling effects of nuclear phosphoinositides.

The function of the nucleolus is intimately connected to cell proliferation, division and growth. Many cancer cells have enlarged nucleoli, and several nucleolar proteins have been linked to tumorigenesis. In order to find proteins whose expression is altered in the nucleoli of leukemic cells, we carried out two-dimensional difference gel electrophoresis (2-D DIGE) analyses. Prohibitin (PHB) and TAR-DNA-binding protein-43 (TDP-43) were strongly expressed in the nucleoli of the pre-B-ALL cell line MHH-CALL3. Our results demonstrate that leukemic cells have differences in their nucleolar protein composition, and suggest that it may be possible to exploit these differences in identification of leukemia subtypes., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Eosinophilic esophagitis, gastroenteritis and colitis are very likely underdiagnosed conditions, and their actual incidence may be increasing. The diagnosis and treatment remain, however, fairly poorly established and are based on inadequate scientific evidence. Differential diagnosis is broad, mainly conditions causing secondary eosinophilia, such as allergies. If the secondary causes have been carefully excluded, the possibility of rare hypereosinophilic syndrome should be considered in prolonged eosinophilia.

Background: We investigated the outcome of childhood cancer within the Tampere University Hospital area, Finland., Patients and Methods: We collected the data from 291 patients, who were 0 to 16 years of age at the time of cancer diagnosis in 1997 to 2006. The largest diagnosis groups were leukemias, malignant tumors of the central nervous system, and lymphomas., Results: Altogether 83% of the patients were alive and at least under long-term remission at the time of the study., Conclusions: Outcome of childhood cancer in Tampere University Hospital area is in line with international results.

The ∼2-megadalton evolutionarily conserved histone deacetylase-associated Rpd3L/Sin3L complex plays critical roles in altering the histone code and repressing transcription of a broad range of genes involved in many aspects of cellular physiology. Targeting of this complex to specific regions of the genome is presumed to rely on interactions involving one or more of at least 10 distinct subunits in the complex. Here we describe the solution structure of the complex formed by the interacting domains of two constitutively associated subunits, mSin3A and SAP30. The mSin3A paired amphipathic helix 3 (PAH3) domain in the complex adopts the left-handed four-helix bundle structure characteristic of PAH domains. The SAP30 Sin3 interaction domain (SID) binds to PAH3 via a tripartite structural motif, including a C-terminal helix that targets the canonical PAH hydrophobic cleft while two other helices and an N-terminal extension target a discrete surface formed largely by the PAH3 α2, α3, and α3' helices. The protein-protein interface is extensive (∼1400 Å(2)), accounting for the high affinity of the interaction and the constitutive association of the SAP30 subunit with the Rpd3L/Sin3L complex. We further show using NMR that the mSin3A PAH3-SAP30 SID complex can bind to nucleic acids, hinting at a role for a nucleolar localization sequence in the SID αA helix in targeting the Rpd3L/Sin3L complex for silencing ribosomal RNA genes.

Decreased leukocyte values in children are usually due to the decrease in the number of neutrophilic granulocytes. This is usually a transient phenomenon associated with viral infections. In infancy and early childhood, immune mediated neutropenias are possible causes of prolonged leukopenia. Causes of rare leukopenias are numerous, including underlying diseases such as congenital myelopathy, a syndrome or malignant hematological disease. The risk of infection associated with neutropenia is increased especially in patients with a production defect of the bone marrow as the underlying cause.

We report a case of a 3.5-year-old female with a very high copy number of human herpesvirus 6 (HHV-6) detected by PCR in blood during acute lymphoblastic leukemia induction therapy. The patient was unsuccessfully treated with antiviral drugs. HHV-6 genome was shown to be constitutively integrated into chromosome 22q-tel, likely to be inherited from the mother who was found to carry high HHV-6 copy number. This case highlights the importance of excluding HHV-6 chromosomal integration before diagnosing HHV-6 infection or reactivation in immunocompromised patients.

Background: Deacetylation of histones plays a fundamental role in gene silencing, and this is mediated by a corepressor complex containing Sin3 as an essential scaffold protein. In this report we examine the evolution of two proteins in this complex, the Sin3-associated proteins SAP30L and SAP30, by using an archive of protein sequences from 62 species., Results: Our analysis indicates that in tetrapods SAP30L is more similar than SAP30 to the ancestral protein, and the two copies in this group originated by gene duplication which occurred after the divergence of Actinopterygii and Sarcopterygii about 450 million years ago (Mya). The phylogenetic analysis and biochemical experiments suggest that SAP30 has diverged functionally from the ancestral SAP30L by accumulating mutations that have caused attenuation of one of the original functions, association with the nuclear matrix. This function is mediated by a nuclear matrix association sequence, which consists of a conserved motif in the C-terminus and the adjacent nucleolar localization signal (NoLS)., Conclusion: These results add further insight into the evolution and function of proteins of the SAP30 family, which share many characteristic with nuclear scaffolding proteins that are intimately involved in regulation of gene expression. Furthermore, SAP30L seems essential to eukaryotic biology, as it is found in animals, plants, fungi, as well as some taxa of unicellular eukaryotes.

Deacetylation of histones is carried out by a corepressor complex in which Sin3A is an essential scaffold protein. Two proteins in this complex, the Sin3A-associated proteins SAP30L and SAP30, have previously been suggested to function as linker molecules between various corepressors. In this report, we demonstrate new functions for human SAP30L and SAP30 by showing that they can associate directly with core histones as well as naked DNA. A zinc-coordinating structure is necessary for DNA binding, one consequence of which is bending of the DNA. We provide evidence that a sequence motif previously shown to be a nuclear localization signal is also a phosphatidylinositol (PI)-binding element and that binding of specific nuclear monophosphoinositides regulates DNA binding and chromatin association of SAP30L. PI binding also decreases the repression activity of SAP30L and affects its translocation from the nucleus to the cytoplasm. Our results suggest that SAP30L and SAP30 play active roles in recruitment of deacetylating enzymes to nucleosomes, and mediate key protein-protein and protein-DNA interactions involved in chromatin remodeling and transcription.

Background: In celiac disease gluten, the disease-inducing toxic component in wheat, induces the secretion of autoantibodies which are targeted against transglutaminase 2 (TG2). These autoantibodies are produced in the small-intestinal mucosa, where they can be found deposited extracellularly below the epithelial basement membrane and around mucosal blood vessels. In addition, during gluten consumption these autoantibodies can also be detected in patients' serum but disappear from the circulation on a gluten-free diet. Interestingly, after adoption of a gluten-free diet the serum autoantibodies disappear from the circulation more rapidly than the small-intestinal mucosal autoantibody deposits. The toxicity of gluten and the secretion of the disease-specific autoantibodies have been widely studied in organ culture of small-intestinal biopsy samples, but results hitherto have been contradictory. Since the mucosal autoantibodies disappear slowly after a gluten-free diet, our aim was to establish whether autoantibody secretion to organ culture supernatants in treated celiac disease patient biopsies is related to the duration of the diet and further to the pre-existence of mucosal TG2-specific IgA deposits in the cultured biopsy samples., Results: In the organ culture system conducted with biopsies derived from treated celiac disease patients, gliadin induced secretion of autoantibodies to culture supernatants, reduced epithelial cell height and increased the density of lamina proprial CD25+ cells. However, these changes could be demonstrated only in biopsies from short-term treated celiac disease patients, where the small-intestinal mucosal TG2-specific IgA autoantibody deposits were still present. Furthermore, in these biopsies autoantibody secretion could be stimulated fully only after a 48-hour gliadin challenge., Conclusion: Our results show that studies focusing on the toxic effects of gliadin in the organ culture system should be carried out with biopsy samples from short-term treated celiac disease patients who are likely still to have mucosal IgA deposits present. In addition to providing an explanation for the discrepancies in previous publications, the present study also enables further validation of the organ culture method.

Covalent modification of histones regulates chromatin structure and gene expression. Sin3A mediates the association of histone deacetylase enzymes with a large number of sequence-specific transcriptional repressors. In this study we characterized three novel transcripts of SAP30L, a recently identified Sin3A-associated protein. These splice variants show significant differences in transcriptional repression capabilities and associating histone deacetylase activities. Furthermore, they differ in binding to Sin3A and in subcellular localization when transiently transfected. These data suggest that the transcriptional repression of a Sin3A corepressor complex can be regulated not only by sequence-specific transcriptional repressors, but also by modification of associated proteins, such as SAP30L.

Objective: Gliadin digestion-resistant peptides are harmful in coeliac disease (CD), and initiate an autoimmune reaction that cause a cascade of symptoms. The role of the endogenous prolyl oligopeptidase (POP) is still not clear, and its activity over gliadin immunoactive peptides has not been fully established. Our objective was therefore to determine the endogenous POP protein level, tissue distribution and total activity in normal and CD epithelia, to evaluate tissue peptidase activity over gliadin peptides, and compare this with activities of mammalian POP and rat intestinal extracts., Material and Methods: POP was assayed in biopsy preparations enzymatically and by Western blot analysis. Distribution was studied by immunohistochemistry using a specific POP antibody. Peptide cleavage was followed by mass spectroscopy-high-performance liquid chromatography (MS-HPLC)., Results: There was no difference in POP activity between normal and CD samples, but those from active CD subjects had an even higher ability to degrade the 33-mer peptide than those from treated CD and healthy humans. POP locates intracellularly in epithelia, similarly to dipeptidyl peptidase IV (DPPIV), but the latter is clearly found in normal microvilli but less so in diseased microvilli. Mammalian POP is unable to digest 33-mer peptide, which, conversely, is a POP inhibitor. Rat intestine is more effective than human intestine in cleaving the 33-mer peptide. However, the products are still harmful epitopes. A surplus of POP eliminates 12-mer and 19-mer peptide products., Conclusions: The results rule out a causative role of POP in the pathogenesis of CD and strongly suggest that other peptidases are needed to eliminate gliadin-derived, immunoactive and toxic peptides larger than 33-mer, which is a POP inhibitor.

The VHS (Vps-27, Hrs and STAM) domain is a 140 residue long domain present in the very NH2-terminus of at least 60 proteins. Based on their functional characteristics and on recent data on the involvement of VHS in cargo recognition in trans-Golgi, VHS domains are considered to have a general membrane targeting/cargo recognition role in vesicular trafficking. Structurally, VHS is a right-handed superhelix of eight helices with charged surface patches probably serving as sites of protein-protein recognition and docking.

STAM/EAST/Hbp family of proteins consists of eight members well conserved from yeast to mammals. The basic domain architecture is comprised of an N-terminal Vps27, Hrs and STAM homology domain, a ubiquitin-interacting motif and a central Src homology-3 domain. Vertebrate members also carry an immunoreceptor tyrosine-based activation motif. STAM/EAST/Hbp proteins become tyrosine-phosphorylated by a variety of cytokines and growth factors. STAM 1 and STAM 2A are involved in cytokine-mediated signalling for DNA synthesis and c-myc induction. EAST and STAM 2A/Hbp play a role in receptor-mediated endo- and exocytosis and probably also in the regulation of actin cytoskeleton. Knockout experiments implicate a role for STAM 1 in neural cell survival. A picture is emerging of STAM/EAST/Hbp proteins acting as integrators of thus far mechanistically disparate cellular signalling events.

We consider genetic models for the inheritance of the particular colour patterns of silver foxes. The models are evaluated by computation of statistical likelihoods based on observations of related foxes in extended pedigrees. Problems caused by incomplete paternity information are addressed by inferences based on phenotypic observations. The unreliability of subjective evaluations of fur colour also provides difficulty, in particular crossfoxes emerge as being difficult to differentiate. No evidence of linkage between Agouti locus and Extension locus is found in this dataset.

Plasma samples of 235 foxes from 38 complete families (14 of arctic foxes, 21 of silver foxes and 3 with arctic x silver fox hybrid offspring) were analysed by one-dimensional horizontal polyacrylamide gel electrophoresis (PAGE) pH 9.0 followed by general-protein staining of gels. A major postalbumin of fox plasma was identified as alpha 1B-glycoprotein (alpha 1B) by using immunoblotting with antiser m specific to human or pig plasma alpha 1B. Four codominant, autosomal alleles of alpha 1B were found in arctic foxes. Two transferrin (TF) alleles (TfF, TfS) were observed in arctic foxes and two (TfD, Tff) in silver foxes; the TF F type of both of the fox species showed identical electrophoretic mobilities. The arctic foxes showed a high degree of polymorphism for both TF and alpha 1B. The silver foxes showed a scarce polymorphism of TF and were monomorphic for alpha 1B. The arctic fox, silver fox and their hybrids could be clearly differentiated from one another by their plasma protein patterns obtained by the PAGE method.