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Higher-order chromatin structures play important roles in regulating multiple biological processes, growth and development, biotic and abiotic stress response. However, little is known about three-dimensional chromatin structures in Paulownia, or about whole-genome chromatin conformational changes that occur in response to Paulownia witches' broom (PaWB) disease. We used high-throughput chromosome conformation capture (Hi-C) to obtain genome-wide profiles of chromatin conformation in healthy and phytoplasma-infected Paulownia fortunei genome. The heatmap results indicated that the strongest interactions between chromosomes were in the telomeres. We confirmed the main structural characteristics, such as A/B compartments, topologically associated domains, and chromatin loops were prominent in Paulownia genome and clearly altered in phytoplasma-infected plants. By combining chromatin Immunoprecipitation sequencing, Hi-C signals, and RNA sequencing data, we inferred that the chromatin structure changed and the modification levels of three histones (H3K4me3/K9ac/K36me3) increased in phytoplasma-infected P. fortunei, which was associated with changes of transcriptional activity. We concluded that epigenetic modifications, transcriptional activity might function in combination to shape chromatin packing in healthy and phytoplasm-infected Paulownia. Finally, 11 genes (such as RPN6, Sec61 subunit alpha), commonly located at specific TAD boundaries, A/B compartment switching, specific loops, and associated with histone marks, were identified and considered as closely related to PaWB stress. Our results provide new insights into the nexus between gene regulation and chromatin conformational alterations in non-model plants upon phytopathogen infection and plant disease resistance. Key words: Paulownia witches' broom; chromatin conformation; histone modification; transcription regulation.

Key Points Non-RAR gene rearrangements have been associated with patients with AML resembling APL but the underlying pathogenesis is unclear.NUP98-JADE2 perturbs wild-type JADE2 and retinoic acid signaling thereby contributing to an APL-like phenotype., Acute promyelocytic leukemia (APL) is a specific subtype of acute myeloid leukemia (AML) characterized by block of differentiation at the promyelocytic stage and the presence of PML-RARA fusion. In rare instances, RARA is fused with other partners in variant APL. More infrequently, non-RARA genes are rearranged in AML patients resembling APL. However, the underlying disease pathogenesis in these atypical cases is largely unknown. Here, we report the identification and characterization of a NUP98- JADE2 fusion in a pediatric AML patient showing APL-like morphology and immunophenotype. Mechanistically, we showed that NUP98-JADE2 could impair all-trans retinoic acid (ATRA)-mediated transcriptional control and myeloid differentiation. Intriguingly, NUP98-JADE2 was found to alter the subcellular distribution of wild-type JADE2, whose down-regulation similarly led to attenuated ATRA-induced responses and myeloid activation, suggesting that NUP98-JADE2 may mediate JADE2 inhibition. To our knowledge, this is the first report of a NUP98-non-RAR rearrangement identified in an AML patient mimicking APL. Our findings suggest JADE2 as a novel myeloid player involved in retinoic acid-induced differentiation. Despite lacking a rearranged RARA, our findings implicate that altered retinoic acid signaling by JADE2 disruption may underlie the APL-like features in our case, corroborating the importance of this signaling in APL pathogenesis.

Cotton that produces natural fiber materials for the textile industry is one of the most important crops in the world. Class II KNOX proteins are often considered as transcription factors in regulating plant secondary cell wall (SCW) formation. However, the molecular mechanism of the KNOX transcription factors-regulated SCW synthesis in plants (especially in cotton) remains unclear in details so far. In this study, we show a cotton class II KNOX protein (GhKNL1) as a transcription repressor functioning in fiber development. The GhKNL1-silenced transgenic cotton produced longer fibers with thicker SCWs, whereas GhKNL1 dominant repression transgenic lines displayed the opposite fiber phenotype, compared with controls. Further experiments revealed that GhKNL1 could directly bind to promoters of GhCesA4-2/4-4/8-2 and GhMYB46 for modulating cellulose synthesis during fiber SCW development of cotton. On the other hand, GhKNL1 could also suppress expressions of GhEXPA2D/4A-1/4D-1/13A through binding to their promoters for regulating fiber elongation of cotton. Taken together, these data revealed GhKNL1 functions in fiber elongation and SCW formation by directly repressing expressions of its target genes related to cell elongation and cellulose synthesis. Thus, our data provide an effective clue for potentially improving fiber quality by genetic manipulation of GhKNL1 in cotton breeding. This article is protected by copyright. All rights reserved.

C4 plants partition photosynthesis enzymes between the bundle sheath (BS) and the mesophyll (M) cells for the better delivery of CO2 to RuBisCO and to reduce photorespiration. To better understand how C4 photosynthesis is regulated at the transcriptional level, we performed RNA-seq, ATAC-seq, ChIP-seq, and Bisulfite-seq (BS-seq) on BS and M cells isolated from maize leaves. By integrating differentially expressed genes with chromatin features, we found that chromatin accessibility coordinates with epigenetic features, especially H3K27me3 modification and CHH methylation, to regulate cell type-preferentially enriched gene expression. Not only the chromatin accessible regions (ACRs) proximal to the genes (pACRs) but also the distal ACRs (dACRs) are determinants of cell type-preferentially enriched expression. We further identified cell type-preferentially enriched motifs, e.g., AAAG for BS cells and TGACC/T for M cells and determined their corresponding transcription factors - DOFs and WRKYs. The complex interaction between cis and trans factors in the preferential expression of C4 genes was also observed. Interestingly, cell type-preferentially enriched gene expression can be fine-tuned by the coordination of multiple chromatin features. Such coordination may be critical in ensuring the cell type-specific function of key C4 genes. Based on the observed cell type-preferentially enriched expression pattern and coordinated chromatin features, we predicted a set of functionally unknown genes, e.g., Zm00001d042050 and Zm00001d040659, to be potential key C4 genes. Our findings provide deep insight into the architectures associated with C4 gene expression and could serve as a valuable resource to further identify the regulatory mechanisms present in C4 species.

High protein diet (HPD) is an affordable and positive approach in prevention and treatment of many diseases. It is believed that transcriptional regulation is responsible for adaptation after HPD feeding and Kruppel-like factor 15 (KLF15), a zinc finger transcription factor that has been proved to perform transcriptional regulation over amino acid, lipid and glucose metabolism, is known to be involved at least in part in this HPD response. To gain more insight into molecular mechanisms by which HPD controls expressions of genes involved in amino acid metabolism in the liver, we performed RNA-seq analysis of mice fed HPD for a short period (3 days). Compared to a low protein diet, HPD feeding significantly increased hepatic expressions of enzymes involved in the breakdown of all the 20 amino acids. Moreover, using KLF15 knockout mice and in vivo Ad-luc analytical system, we were able to identify Cth (cystathionine gamma-lyase) as a new target gene of KLF15 transcription as well as Ast (aspartate aminotransferase) as an example of KLF15-independent gene despite its remarkable responsiveness to HPD. These findings provide us with a clue to elucidate the entire transcriptional regulatory mechanisms of amino acid metabolic pathways.

Candida albicans is an opportunistic human fungal pathogen that exists in normal flora but can cause infection in immunocompromised individuals. The transition to pathogenic C. albicans requires a change of various gene expressions. Because histone-modifying enzymes can regulate gene expression, they are thought to control the virulence of C. albicans. Indeed, the absence of H3 lysine 4 (H3K4) methyltransferase Set1 has been shown to reduce the virulence of C. albicans; however, Set1-regulated genes responsible for this attenuated virulence phenotype remain unknown. Here, we demonstrated that Set1 positively regulates the expression of mitochondrial protein genes by methylating H3K4. In particular, levels of cellular mitochondrial reactive oxygen species (ROS) were higher in Δset1 than in the wild-type due to the defect of those genes’ expression. Set1 deletion also increases H2O2 sensitivity and prevents proper colony formation when interacting with macrophage in vitro, consistent with its attenuated virulence in vivo. Together, these findings suggest that Set1 is required to regulate proper cellular ROS production by positively regulating the expression of mitochondrial protein genes and subsequently sustaining mitochondrial membrane integrity. Consequently, C. albicans maintains proper ROS levels via Set1-mediated transcriptional regulation, thus establishing a rapid defense against external ROS generated by the host.

Biosynthesis mechanism of the only animal resin, lac resin remains elusive to the scientific community. An attempt to identify the genes of resin biosynthesis in lac insects was made through SSH (Suppression Subtraction Hybridization) library by subtracting genes of resin non secreting stage (neonate nymphs) from the resin secreting stage (adult female) of the lac insect. SSH library yielded 107 non redundant clones with 61 clones having sequences homologous with known functions (defence, development, metabolism, regulation, transport, cell division, respiration, structural role), 7 clones having hypothetical proteins or uncharacterized proteins and 39 clones did not find any matches. Among the differentially expressed genes, few putative genes of terpene biosynthesis, fatty acid biosynthesis and transcriptional regulation were identified. Out of them, an IDS (Isopentenyl Diphosphate Synthase) type decaprenyl diphosphate synthase and a desaturase gene, acyl-CoA delta desaturase were cloned from lac insects and sequenced. Their expression levels were found to be more in lac resin synthesis stages such as settled nymphs and fertilized female insects in comparison with resin non secreting stage, crawlers (neonate nymphs). It gives a clear indication of their role in lac resin biosynthesis due to the correlation of their expression level with resin biosynthesis in lac insects.

Gene expression programs and concomitant chromatin regulation change dramatically during the maturation of postmitotic neurons. Subnuclear positioning of gene loci is relevant to transcriptional regulation. However, little is known about subnuclear genome positioning in neuronal maturation. Using cultured murine hippocampal neurons, we found genomic locus 14qD2 to be enriched with genes that are upregulated during neuronal maturation. Reportedly, the locus is homologous to human 8p21.3, which has been extensively studied in neuropsychiatry and neurodegenerative diseases. Mapping of the 14qD2 locus in the nucleus revealed that it was relocated from the nuclear periphery to the interior. Moreover, we found a concomitant decrease in lamin B1 expression. Overexpression of lamin B1 in neurons using a lentiviral vector prevented the relocation of the 14qD2 locus and repressed the transcription of the Egr3 gene on this locus. Taken together, our results suggest that reduced lamin B1 expression during the maturation of neurons is important for appropriate subnuclear positioning of the genome and transcriptional programs.

Transcription is the principal control point for bacterial gene expression, and it enables a global cellular response to an intracellular or environmental trigger. Transcriptional regulation is orchestrated by transcription factors, which activate or repress transcription of target genes by modulating the activity of RNA polymerase. Dissecting the nature and precise choreography of these interactions is essential for developing a molecular understanding of transcriptional regulation. While the contribution of X-ray crystallography has been invaluable, the ‘resolution revolution’ of cryo-electron microscopy has transformed our structural investigations, enabling large, dynamic and often transient transcription complexes to be resolved that in many cases had resisted crystallisation. In this review, we highlight the impact cryo-electron microscopy has had in gaining a deeper understanding of transcriptional regulation in bacteria. We also provide readers working within the field with an overview of the recent innovations available for cryo-electron microscopy sample preparation and image reconstruction of transcription complexes.

The function of the skin as a barrier against a dry environment evolved in a common ancestor of terrestrial vertebrates such as mammals and birds. However, it is unknown which elements of the genetic program of skin barrier formation are evolutionarily ancient and conserved. In this study, we determined the transcriptomes of chicken keratinocytes (KCs) grown in monolayer culture and in an organotypic model of avian skin. The differentiation-associated changes in global gene expression were compared with previously published transcriptome changes of human KCs cultured under equivalent conditions. We found that specific keratins and genes of the epidermal differentiation complex were upregulated during the differentiation of both chicken and human KCs. Likewise, the transcriptional upregulation of genes that control the synthesis and transport of lipids, anti-inflammatory cytokines of the IL-1 family, protease inhibitors, and other regulators of tissue homeostasis was conserved in the KCs of both species. However, some avian KC differentiation-associated transcripts lack homologs in mammals and vice versa, indicating a genetic basis for taxon-specific skin features. The results of this study reveal an evolutionarily ancient program in which dynamic gene transcription controls the metabolism and transport of lipids as well as other core processes during terrestrial skin barrier formation.

RNA-binding proteins (RBPs) regulate cell physiology via the formation of ribonucleic-protein complexes with coding and non-coding RNAs. RBPs have multiple functions in the same cells; however, the precise mechanism through which their pleiotropic functions are determined remains unknown. In this study, we revealed the multiple inhibitory functions of heterogeneous nuclear ribonucleoprotein K (hnRNPK) for myogenic differentiation. We first identified hnRNPK as a lncRNA Myoparr binding protein. Gain- and loss-of-function experiments showed that hnRNPK repressed the expression of myogenin at the transcriptional level. The hnRNPK-binding region of Myoparr was required to repress myogenin expression. Moreover, hnRNPK repressed the expression of a set of genes coding for aminoacyl-tRNA synthetases in a Myoparr-independent manner. Mechanistically, hnRNPK regulated the eIF2α/Atf4 pathway, one branch of the intrinsic pathways of the endoplasmic reticulum sensors, in differentiating myoblasts. Thus, our findings demonstrate that hnRNPK plays lncRNA-associated and - independent multiple roles during myogenic differentiation, indicating that the analysis of lncRNA-binding proteins will be useful for elucidating both the physiological functions of lncRNAs and the multiple functions of RBPs.

Salsola drummondii is a perennial habitat-indifferent halophyte growing in saline and non-saline habitats of the Arabian hyperarid deserts. It offers an invaluable opportunity to examine the molecular mechanisms of salt tolerance. The present study was conducted to elucidate these mechanisms through transcriptome profiling of seedlings grown from seeds collected in a saline habitat. The Illumina Hiseq 2500 platform was employed to sequence cDNA libraries prepared from shoots and roots of non-saline-treated plants (controls) and plants treated with 1200 mM NaCl. Transcriptomic comparison between salt-treated and control samples resulted in 17,363 differentially expressed genes (DEGs), including 12,000 upregulated genes (7870 in roots, 4130 in shoots) and 5363 downregulated genes (4258 in roots and 1105 in shoots), and 272,643 unigenes were functionally annotated. The majority of identified DEGs are known to be involved in transcription regulation (79), signal transduction (82), defense metabolism (101), transportation (410), cell wall metabolism (27), regulatory processes (392), respiration (85), chaperoning (9), and ubiquitination (98) during salt tolerance. This study identified potential genes associated with the salt tolerance of S. drummondii and demonstrated that this tolerance may depend on the induction of certain genes in shoot and root tissues. These gene expressions were validated using reverse-transcription quantitative PCR, the results of which were consistent with transcriptomics results. To the best of our knowledge, this is the first study providing genetic information on salt tolerance mechanisms in S. drummondii. This article is protected by copyright. All rights reserved.

This bioinformatics study aimed to identify ETV4 transcription factor oncogenes and outline anticancer drugs for these genes. First, we collected known 61 ETV4 cancer targets that were framed as two classes of queries to screen against the multiomics resources in GeneMANIA. This method accessed and added functionally similar 20 genes to each set. These data were interpreted by hub genes, network clustering, gene ontology, and pathway analyses, and the results confirmed that all resultant genes were cancer promoters. The ETS-binding motifs were identified from the promoter regions of these genes. Thus, 23 ETV4 targets were figured and those involved in oncogenesis were filtered as the following 16 putative nodes: MMP8, MMP14, KDR, BRIP1, CXCR1, GRB14, SHC2, SHC4, SH2B1, SH2B2, INPPL1, PTPN3, GNG12, SEMA4D, RHOA, and SPSB2. The transcriptional regulation of these oncogenes was coordinated by an extensive miRNA network that found to deregulate many cancer pathways. Using DgIb database, the high quality 6 oncogene-drug combinations (MMP8-CHEMBL1231240, MMP8-Aminomethylamide, CXCR1-Reparixin, SEMA4D-Pepinemab, RHOA-Clausine E, and SPSB2-CHEMBL175296) were proposed. These findings may advance our understanding of novel neoplastic gene nexus of ETV4 and design treatment strategies for its modulation.

Ripening of fleshy fruits involves both diverse post-translational modifications (PTMs) and dynamic transcriptional reprogramming, but the interconnection between PTMs, such as protein phosphorylation and transcriptional regulation, in fruit ripening remains to be deciphered. Here, we conducted a phosphoproteomic analysis during banana (Musa acuminata) ripening and identified 63 unique phosphopeptides corresponding to 49 proteins. Among them, a Musa acuminata basic leucine zipper transcription factor21 (MabZIP21) displayed elevated phosphorylation level in the ripening stage. MabZIP21 transcript and phosphorylation abundance increased during banana ripening. Genome-wide MabZIP21 DNA binding assays revealed MabZIP21-regulated functional genes contributing to banana ripening, and electrophoretic mobility shift assay, chromatin immunoprecipitation coupled with quantitative polymerase chain reaction, and dual-luciferase reporter analyses demonstrated that MabZIP21 stimulates the transcription of a subset of ripening-related genes via directly binding to their promoters. Moreover, MabZIP21 can be phosphorylated by MaMPK6-3, which plays a role in banana ripening, and T318 and S436 are important phosphorylation sites. Protein phosphorylation enhanced MabZIP21-mediated transcriptional activation ability, and transient overexpression of the phosphomimetic form of MabZIP21 accelerated banana fruit ripening. Additionally, MabZIP21 enlarges its role in transcriptional regulation by activating the transcription of both MaMPK6-3 and itself. Taken together, this study reveals an important machinery of protein phosphorylation in banana fruit ripening in which MabZIP21 is a component of the complex phosphorylation pathway linking the upstream signal mediated by MaMPK6-3 with transcriptional controlling of a subset of ripening-associated genes.

The pathways regulated in ectomycorrhizal (EcM) plant hosts during the establishment of symbiosis are not as well understood when compared to the functional stages of this mutualistic interaction. Our study used the EcM host Eucalyptus grandis to elucidate symbiosis-regulated pathways across the three phases of this interaction. Using a combination of RNA sequencing and metabolomics we studied both stage-specific and core responses of E. grandis during colonization by Pisolithus microcarpus. Using exogenous manipulation of the abscisic acid (ABA), we studied the role of this pathway during symbiosis establishment. Despite the mutualistic nature of this symbiosis, a large number of disease signalling TIR-NBS-LRR genes were induced. The transcriptional regulation in E. grandis was found to be dynamic across colonization with a small core of genes consistently regulated at all stages. Genes associated to the carotenoid/ABA pathway were found within this core and ABA concentrations increased during fungal integration into the root. Supplementation of ABA led to improved accommodation of P. microcarpus into E. grandis roots. The carotenoid pathway is a core response of an EcM host to its symbiont and highlights the need to understand the role of the stress hormone ABA in controlling host-EcM fungal interactions.

The molecular mechanisms of quantitative resistance (QR) to fungal pathogens and their relationships with growth pathways are poorly understood. We identified tomato TRK1 (TPK1b Related Kinase1) and determined its functions in tomato QR and plant growth. TRK1 is a receptor-like cytoplasmic kinase that complexes with tomato LysM Receptor Kinase (SlLYK1). SlLYK1 and TRK1 are required for chitin-induced fungal resistance, accumulation of reactive oxygen species, and expression of immune response genes. Notably, TRK1 and SlLYK1 regulate SlMYC2, a major transcriptional regulator of jasmonic acid (JA) responses and fungal resistance, at transcriptional and post-transcriptional levels. Further, TRK1 is also required for maintenance of proper meristem growth, as revealed by the ectopic meristematic activity, enhanced branching, and altered floral structures in TRK1 RNAi plants. Consistently, TRK1 interacts with SlCLV1 and SlWUS, and TRK1 RNAi plants show increased expression of SlCLV3 and SlWUS in shoot apices. Interestingly, TRK1 suppresses chitin-induced gene expression in meristems but promotes expression of the same genes in leaves. SlCLV1 and TRK1 perform contrasting functions in defense but similar functions in plant growth. Overall, through molecular and biochemical interactions with critical regulators, TRK1 links upstream defense and growth signals to downstream factor in fungal resistance and growth homeostasis response regulators.

Neuron-restrictive silencing factor (NRSF), also known as RE-1 silencing transcription factor (REST), has pivotal functions in many neuron-specific genes. Previous studies revealed that neuron-specific alternative splicing (AS) of REST produces divergent forms of REST variants and provides regulatory complexity in the nervous system. However, the biological significance of these variants in the regulation of neuronal activities remains to be clarified. Here, we revealed that Charlatan (Chn), a Drosophila REST-like molecule, is also regulated by neuron-specific AS. Neuron-specific AS produced six divergent variants of Chn proteins, one of which preferentially localized to axons. A small sequence of this variant was especially important for the axonal localization. Our data suggest that some variants have roles beyond the transcriptional regulation of neuronal activities.

Hui Yu,1 Weikang Guo,2 Yunduo Liu,2 Yaoxian Wang2 1Cardiopulmonary Function Department, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, 150081, People’s Republic of China; 2Gynecological Department, Harbin Medical University Cancer Hospital, Harbin, Heilongjiang, 150081, People’s Republic of ChinaCorrespondence: Yaoxian WangGynecological Department, Harbin Medical University Cancer Hospital, No. 150 Haping Road, Nangang District, Harbin, Heilongjiang, 150081, People’s Republic of ChinaTel +86-0451-86298578Email wyxxs012@126.comPurpose: The variation in inflammation in chronic obstructive pulmonary disease (COPD) between individuals is genetically determined. This study aimed to identify gene signatures of COPD through bioinformatics analysis based on multiple gene sets and explore their immune characteristics and transcriptional regulation mechanisms.Methods: Data from four microarrays were downloaded from the Gene Expression Omnibus database to screen differentially expressed genes (DEGs) between COPD patients and controls. Weighted gene co-expression network analysis was applied to identify trait-related modules and then select key module-related DEGs. The optimized gene set of signatures was obtained using the least absolute shrinkage and selection operator (LASSO) regression analysis. The CIBERSORT algorithm and Pearson correlation test were used to analyze the relationship between gene signatures and immune cells. Finally, public databases were used to predict the transcription factors (TFs) and upstream miRNAs.Results: A total of 127 DEGs in COPD were identified from the combined dataset. By considering the intersection of DEGs and genes in two trait-related modules, 83 key module-related DEGs were identified, which were mainly enriched in interleukin-related pathways. Seven-gene signatures, including MTHFD2, KANK3, GFPT2, PHLDA1, HS3ST2, FGG, and RPS4Y1, were further selected using the LASSO algorithm. These gene signatures showed the predictive potential for COPD risks and were significantly correlated with 18 types of immune cells. Finally, nine miRNAs and three TFs were predicted to target MTHFD2, GFPT2, PHLDA1, and FGG.Conclusion: We proposed the seven-gene-signature to predict COPD risk and explored its potential immune characteristics and regulatory mechanisms.Keywords: COPD, gene signatures, immune infiltration, transcriptional regulation

While most genes’ expression levels are proportional to cell volumes, some genes exhibit nonlinear scaling between their expression levels and cell volume. Therefore, their mRNA and protein concentrations change as the cell volume increases, which often have crucial biological functions such as cell-cycle regulation. However, the biophysical mechanism underlying the nonlinear scaling between gene expression and cell volume is still unclear. In this work, we show that the nonlinear scaling is a direct consequence of the heterogeneous recruitment abilities of promoters to RNA polymerases based on a gene expression model at the whole-cell level. Those genes with weaker (stronger) recruitment abilities than the average ability spontaneously exhibit superlinear (sublinear) scaling with cell volume. Analysis of the promoter sequences and the nonlinear scaling of Saccharomyces cerevisiae’s mRNA levels shows that motifs associated with transcription regulation are indeed enriched in genes exhibiting nonlinear scaling, in concert with our model., Expression levels of most genes are proportional to cell volumes, although some genes exhibit nonlinear scaling of expression levels with cell volume. Here the authors provide a model that reveals nonlinear scaling is a direct consequence of heterogeneous recruitment abilities of promoters to RNA polymerases.

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death due to cancer in the world. Therefore, the identification of novel druggable targets is urgently needed. Tribbles proteins belong to a pseudokinase family, previously recognized in CRC as oncogenes and potential therapeutic targets. Here, we analyzed the expression of TRIB1, TRIB2, and TRIB3 simultaneously in 33 data sets from CRC based on available GEO profiles. We show that all three Tribbles genes are overrepresented in CRC cell lines and primary tumors, though depending on specific features of the CRC samples. Higher expression of TRIB2 in the tumor microenvironment and TRIB3 overexpression in an early stage of CRC development, unveil a potential and unexplored role for these proteins in the context of CRC. Differential Tribbles expression was also explored in diverse cellular experimental conditions where either genetic or pharmacological approaches were used, providing novel hints for future research. This comprehensive bioinformatic analysis provides new insights into Tribbles gene expression and transcript regulation in CRC. info:eu-repo/semantics/publishedVersion

Transcriptome profiling of maize inbred and hybrid seedlings subjected to heat or cold stress was used to identify key cis-regulatory elements and develop models to predict gene expression responses., Changes in gene expression are important for responses to abiotic stress. Transcriptome profiling of heat- or cold-stressed maize genotypes identifies many changes in transcript abundance. We used comparisons of expression responses in multiple genotypes to identify alleles with variable responses to heat or cold stress and to distinguish examples of cis- or trans-regulatory variation for stress-responsive expression changes. We used motifs enriched near the transcription start sites (TSSs) for thermal stress-responsive genes to develop predictive models of gene expression responses. Prediction accuracies can be improved by focusing only on motifs within unmethylated regions near the TSS and vary for genes with different dynamic responses to stress. Models trained on expression responses in a single genotype and promoter sequences provided lower performance when applied to other genotypes but this could be improved by using models trained on data from all three genotypes tested. The analysis of genes with cis-regulatory variation provides evidence for structural variants that result in presence/absence of transcription factor binding sites in creating variable responses. This study provides insights into cis-regulatory motifs for heat- and cold-responsive gene expression and defines a framework for developing models to predict expression responses across multiple genotypes.

Disordered chromatin remodeling regulation has emerged as an essential driving factor for cancers. Imitation switch (ISWI) family are evolutionarily conserved ATP-dependent chromatin remodeling complexes, which are essential for cellular survival and function through multiple genetic and epigenetic mechanisms. Omics sequencing and a growing number of basic and clinical studies found that ISWI family members displayed widespread gene expression and genetic status abnormalities in human cancer. Their aberrant expression is closely linked to patient outcome and drug response. Functional or componential alteration in ISWI-containing complexes is critical for tumor initiation and development. Furthermore, ISWI-non-coding RNA regulatory networks and some non-coding RNAs derived from exons of ISWI member genes play important roles in tumor progression. Therefore, unveiling the transcriptional regulation mechanism underlying ISWI family sparked a booming interest in finding ISWI-based therapies in cancer. This review aims at describing the current state-of-the-art in the role of ISWI subunits and complexes in tumorigenesis, tumor progression, immunity and drug response, and presenting deep insight into the physiological and pathological implications of the ISWI transcription machinery in cancers.

Vibrio vulnificus can utilize the xenosiderophore desferrioxamine B (DFOB) as an iron source under iron-restricted conditions. We previously identified in V. vulnificus that transcription of the desA gene encoding the outer membrane receptor for ferrioxamine B (FOXB) is activated by the AraC-type transcriptional regulator encoded by desR together with DFOB. In this study, we overexpressed and purified DesR as a glutathione S-transferase-fused protein and examined interaction between the promoter region of desA and DesR. Electrophoretic mobility shift assay (EMSA) revealed that DesR directly binds to the regulatory region of desA, and this binding was enhanced by the presence of DFOB in a concentration-dependent manner, while the presence of FOXB did not affect the potentiation of their binding. Moreover, EMSA identified that DNA fragments lacking a probable DesR binding sequence were unable to form complexes with DesR. Finally, deoxyribonuclease I footprinting assay demonstrated that the DNA binding sequence of DesR is located between -27 and -50 nucleotides upstream of the desA transcription start site. These results strongly indicate that DesR can directly activate the transcription of desA in cooperation with DFOB, which acts as a coactivator for DesR.

Dickeya zeae is the causal agent of rice foot rot disease. The pathogen is known to rely on a range of virulence factors, including phytotoxin zeamines, extracellular enzymes, cell motility, and biofilm, which collectively contribute to the establishment of infections. Phytotoxin zeamines play a critical role in bacterial virulence; signalling pathways and regulatory mechanisms that govern bacterial virulence remain unclear. In this study, we identified a transcriptional regulator OhrR (organic hydroperoxide reductase regulator) that is involved in the regulation of zeamine production in D. zeae EC1. The OhrR null mutant was significantly attenuated in its virulence against rice seed, potato tubers and radish roots. Phenotype analysis showed that OhrR was also involved in the regulation of other virulence traits, including the production of extracellular cellulase, biofilm formation, and swimming/swarming motility. DNA electrophoretic mobility shift assay showed that OhrR directly regulates the transcription of key virulence genes and genes encoding bis‐(3′–5′)‐cyclic dimeric guanosine monophosphate synthetases. Furthermore, OhrR positively regulates the transcription of regulatory genes slyA and fis through binding to their promoter regions. Our findings identify a key regulator of the virulence of D. zeae and add new insights into the complex regulatory network that modulates the physiology and virulence of D. zeae., OhrR is crucial for regulatory of virulence factors production and pathogenicity, and regulates SlyA and Fis to control the expression of downstream virulence genes.

CCCTC-binding factor (CTCF) plays fundamental roles in transcriptional regulation and chromatin architecture maintenance. CTCF is also a tumour suppressor frequently mutated in cancer, however, the structural and functional impact of mutations have not been examined. We performed molecular and structural characterisation of five cancer-specific CTCF missense zinc finger (ZF) mutations occurring within key intra- and inter-ZF residues. Functional characterisation of CTCF ZF mutations revealed a complete (L309P, R339W, R377H) or intermediate (R339Q) abrogation as well as an enhancement (G420D) of the anti-proliferative effects of CTCF. DNA binding at select sites was disrupted and transcriptional regulatory activities abrogated. Molecular docking and molecular dynamics confirmed that mutations in residues specifically contacting DNA bases or backbone exhibited loss of DNA binding. However, R339Q and G420D were stabilised by the formation of new primary DNA bonds, contributing to gain-of-function. Our data confirm that a spectrum of loss-, change- and gain-of-function impacts on CTCF zinc fingers are observed in cell growth regulation and gene regulatory activities. Hence, diverse cellular phenotypes of mutant CTCF are clearly explained by examining structure–function relationships. Supplementary Information The online version contains supplementary material available at 10.1007/s00018-021-03946-z.

Gonadotropin releasing hormone (GnRH) neurons play a crucial role in the development and functioning of the hypothalamus-pituitary-gonadal (HPG) axis, ultimately acting as the master controller for the fecundity of an organism. GnRH decapeptide is essential for expression of luteinizing hormone and follicle stimulating hormone, which are indispensable for gametogenesis and gonadal steroidogenesis in the vertebrates. Over the last couple of decades, extensive research has been conducted to understand factors responsible for regulating expression of GnRH-I. It has been established that GnRH-I gets regulated directly by various transcription factors that are part of epigenetic regulation as the binding sites for factors such as OCT1, PBX1B, DLX2, MSX1, etc. have been identified in the 5’ promoter and enhancer region of the GnRH-I gene. Indirect regulation of the GnRH-I gene by various glial and other neuronal inputs has also been studied. Role of kisspeptin and KNDy neurons has proved to be of prime importance for the regulation of GnRH-I. GnRH-I gene receives various inhibitory and excitatory signals, resulting in formation of a very complex system responsible for triggering or pausing its expression. Due to its complicated and complex nature, understanding of the regulatory network involved in regulation of GnRH-I is very limited. Further research is required to understand the role of epigenetics and environmental factors triggering the regulatory network of GnRH-I.

Members of the AP-1 family of transcription factors are immediate early genes being modulated by different extracellular signals. The aim of this review is to highlight the important roles of AP-1 members in transcriptional regulation of genes important for testicular Leydig cell function and male testosterone production. A search of the relevant literature was performed in Google Scholar and NCBI Pubmed for AP-1 members and Leydig cells. Additional information was accessed from references of relevant articles. Only primary data from original peer-reviewed articles was considered for this review. Different signaling pathways important for Leydig cells’ functions are involved in the regulation of the activity of AP-1 members. These transcription factors participate in the regulation of genes related to different biological processes important for Leydig cells. We conclude that members of the AP-1 family of transcription factors play critical roles in the regulation of Leydig cell proliferation, steroidogenesis, and cell-to-cell communication.

As a multicellular organism, rice flourishes relying on gene expression diversity among cells of various functions. However, cellular-resolution transcriptome features are yet to be fully recognized, let alone cell-specific transcriptional responses to environmental stimuli. In this study, we apply single-cell RNA sequencing to both shoot and root of rice seedlings growing in Kimura B nutrient solution or exposed to various abiotic stresses and characterize transcriptomes for a total of 237,431 individual cells. We identify 15 and 9 cell types in the leaf and root, respectively, and observe that common transcriptome features are often shared between leaves and roots in the same tissue layer, except for endodermis or epidermis. Abiotic stress stimuli alter gene expression largely in a cell type-specific manner, but for a given cell type, different stresses often trigger transcriptional regulation of roughly the same set of genes. Besides, we detect proportional changes in cell populations in response to abiotic stress and investigate the underlying molecular mechanisms through single-cell reconstruction of the developmental trajectory. Collectively, our study represents a benchmark-setting data resource of single-cell transcriptome atlas for rice seedlings and an illustration of exploiting such resources to drive discoveries in plant biology.

Macrobrachium rosenbergii is a typical aquatic organism with reversible gonadal development that is regulated by gene expression. The role of transcription factors in gonadal in adult shrimps remains unclear in M. rosenbergii. In this study, we sequenced the transcriptomes of adult shrimp testes, ovaries, and androgenic glands using second-generation sequencing. In total, 24,007 genes were identified and 9,199 differentially expressed genes (DEGs) were identified by pairwise comparison. There were 272 differentially expressed transcription factors (TFs); 107, 152, and 13 differentially expressed TFs were identified in the testes, ovaries, and androgenic glands by three pairwise comparisons, respectively. GO and KEGG analyses of the TFs and DEGs involved in the MAPK signaling and transcriptional regulation pathways and play key roles in the cell cycle of the testes, whereas involved in the thyroid hormone signaling pathway and neuroactive ligand–receptor interaction play important roles in the ovary. We determined the existence of networks comprising important TFs related to sex development in adult M. rosenbergii gonads. The key TFs were Piwi (expressed only in the testes and ovaries) and Argonaute 3 (expressed only in the ovaries), which might be involved in the regulation of testes and ovary development.

BackgroundCellular RNA-binding proteins (RBPs) have multiple roles in post-transcriptional control, and some are shown to bind DNA. However, the global localization and the general chromatin-binding ability of RBPs are not well-characterized and remain undefined in hematopoietic cells.ResultsWe first provide a full view of RBPs’ distribution pattern in the nucleus and screen for chromatin-enriched RBPs (Che-RBPs) in different human cells. Subsequently, by generating ChIP-seq, CLIP-seq, and RNA-seq datasets and conducting combined analysis, the transcriptional regulatory potentials of certain hematopoietic Che-RBPs are predicted. From this analysis, quaking (QKI5) emerges as a potential transcriptional activator during monocytic differentiation. QKI5 is over-represented in gene promoter regions, independent of RNA or transcription factors. Furthermore, DNA-bound QKI5 activates the transcription of several critical monocytic differentiation-associated genes, including CXCL2, IL16, and PTPN6. Finally, we show that the differentiation-promoting activity of QKI5 is largely dependent on CXCL2, irrespective of its RNA-binding capacity.ConclusionsOur study indicates that Che-RBPs are versatile factors that orchestrate gene expression in different cellular contexts, and identifies QKI5, a classic RBP regulating RNA processing, as a novel transcriptional activator during monocytic differentiation.

Due to advances in chip and sequencing technology, several types and numbers of long non-coding RNAs (lncRNAs) have been identified. LncRNAs are defined as non-protein-coding RNA molecules longer than 200 nucleotides, and are now thought as a new frontier in the study of human malignant diseases including NSCLC. Diagnosis of numerous malignant tumors has been closely linked to the differential expression of certain lncRNAs. LncRNAs are involved in gene expression regulation at multiple levels of epigenetics, transcriptional regulation, and post-transcriptional regulation. Mutations, deletions, or abnormal expression levels lead to physiological abnormalities, disease occurrence and are closely associated with human tumor diseases. LncRNAs play a crucial role in cancerous processes as either oncogenes or tumor suppressor genes. The expression of lncRNAs can regulate tumor cell in the proliferation, migration, apoptosis, cycle, invasion, and metastasis. As such, lncRNAs are potential diagnostic and treatment targets for cancer. And that, tumor biomarkers need to be detectable in easily accessible body samples, should be characterized by high specificity and sufficient sensitivity. Herein, it is significant clinical importance to screen and supplement new biomarkers for early diagnosis of lung cancer. This study aimed at systematically describing lncRNAs from five aspects based on recent studies: concepts, classification, structure, molecular mechanism, signal pathway, as well as review lncRNA implications in malignant tumor.

Background Fruit ripening is an intricate developmental process driven by a highly coordinated action of complex hormonal networks. Ethylene is considered as the main phytohormone that regulates the ripening of climacteric fruits. Concomitantly, several ethylene-responsive transcription factors (TFs) are pivotal components of the regulatory network underlying fruit ripening. Calmodulin-binding transcription activator (CAMTA) is one such ethylene-induced TF implicated in various stress and plant developmental processes. Results Our comprehensive analysis of the CAMTA gene family in Durio zibethinus (durian, Dz) identified 10 CAMTAs with conserved domains. Phylogenetic analysis of DzCAMTAs, positioned DzCAMTA3 with its tomato ortholog that has already been validated for its role in the fruit ripening process through ethylene-mediated signaling. Furthermore, the transcriptome-wide analysis revealed DzCAMTA3 and DzCAMTA8 as the highest expressing durian CAMTA genes. These two DzCAMTAs possessed a distinct ripening-associated expression pattern during post-harvest ripening in Monthong, a durian cultivar native to Thailand. The expression profiling of DzCAMTA3 and DzCAMTA8 under natural ripening conditions and ethylene-induced/delayed ripening conditions substantiated their roles as ethylene-induced transcriptional activators of ripening. Similarly, auxin-suppressed expression of DzCAMTA3 and DzCAMTA8 confirmed their responsiveness to exogenous auxin treatment in a time-dependent manner. Accordingly, we propose that DzCAMTA3 and DzCAMTA8 synergistically crosstalk with ethylene during durian fruit ripening. In contrast, DzCAMTA3 and DzCAMTA8 antagonistically with auxin could affect the post-harvest ripening process in durian. Furthermore, DzCAMTA3 and DzCAMTA8 interacting genes contain significant CAMTA recognition motifs and regulated several pivotal fruit-ripening-associated pathways. Conclusion Taken together, the present study contributes to an in-depth understanding of the structure and probable function of CAMTA genes in the post-harvest ripening of durian.

Summary Plant ethylene‐responsive factors (ERFs) play essential roles in cold stress response, but the molecular mechanisms underlying this process remain poorly understood. In this study, we characterized PtrERF9 from trifoliate orange (Poncirus trifoliata (L.) Raf.), a cold‐hardy plant. PtrERF9 was up‐regulated by cold in an ethylene‐dependent manner. Overexpression of PtrERF9 conferred prominently enhanced freezing tolerance, which was drastically impaired when PtrERF9 was knocked down by virus‐induced gene silencing. Global transcriptome profiling indicated that silencing of PtrERF9 resulted in substantial transcriptional reprogramming of stress‐responsive genes involved in different biological processes. PtrERF9 was further verified to directly and specifically bind with the promoters of glutathione S‐transferase U17 (PtrGSTU17) and ACC synthase1 (PtrACS1). Consistently, PtrERF9‐overexpressing plants had higher levels of PtrGSTU17 transcript and GST activity, but accumulated less ROS, whereas the silenced plants showed the opposite changes. Meanwhile, knockdown of PtrERF9 decreased PtrACS1 expression, ACS activity and ACC content. However, overexpression of PtrERF9 in lemon, a cold‐sensitive species, caused negligible alterations of ethylene biosynthesis, which was attributed to perturbed interaction between PtrERF9, along with lemon homologue ClERF9, and the promoter of lemon ACS1 gene (ClACS1) due to mutation of the cis‐acting element. Taken together, these results indicate that PtrERF9 acts downstream of ethylene signalling and functions positively in cold tolerance via modulation of ROS homeostasis by regulating PtrGSTU17. In addition, PtrERF9 regulates ethylene biosynthesis by activating PtrACS1 gene, forming a feedback regulation loop to reinforce the transcriptional regulation of its target genes, which may contribute to the elite cold tolerance of Poncirus trifoliata.

Our study attempted to explore the mechanism underlying the role of LuxR family transcriptional regulator abaR in biofilm formation by Acinetobacter baumannii. The abaR gene was knocked out in ATCC 17978 strain using homologous recombination method. The growth curve and biofilm formation were measured in the wild type and abaR gene knockdown strains. Transcriptome sequencing was performed in the wild type and abaR gene knockdown strains following 8 h of culture. The growth curve in the abaR gene knockdown strain was similar to that of the wild-type strain. Biofilm formation significantly declined in the abaR gene knockdown strain at 8 and 48 h after culture. A total of 137 differentially expressed genes (DEGs) were obtained including 20 downregulated DEGs and 117 upregulated DEGs. Genes with differential expression were closely related to viral procapsid maturation (GO:0046797), acetoin catabolism (GO:0045150), carbon metabolism (ko01200), and the glycolysis/gluconeogenesis (ko00010)-related pathways. The results of the eight verified expression DEGs were consistent with the results predicted by bioinformatics. AbaR gene knockdown significantly affected biofilm formation by A. baumannii ATCC 17978 strain. The glycolysis/gluconeogenesis pathways were significantly dysregulated and induced by abaR gene knockdown in A. baumannii. Supplementary Information The online version contains supplementary material available at 10.1007/s00284-021-02654-y.

To isolate the genetic locus responsible for saline–alkaline stress tolerance, we developed a high‐throughput activation tagging‐based T‐DNA insertion mutagenesis method using the model rice (Oryza sativa L.) variety Kitaake. One of the activation‐tagged insertion lines, activation tagging 7 (AC7), showed increased tolerance to saline–alkaline stress. This phenotype resulted from the overexpression of a gene that encodes a SET DOMAIN GROUP 721 protein with H3K4 methyltransferase activity. Transgenic plants overexpressing OsSDG721 showed saline–alkaline stress‐tolerant phenotypes, along with increased leaf angle, advanced heading and ripening dates. By contrast, ossdg721 loss‐of‐function mutants showed increased sensitivity to saline–alkaline stress characterized by decreased survival rates and reduction in plant height, grain size, grain weight and leaf angle. RNA sequencing (RNA‐seq) analysis of wild‐type Kitaake and ossdg721 mutants indicated that OsSDG721 positively regulates the expression level of HIGH‐AFFINITY POTASSIUM (K+ ) TRANSPORTER1;5 (OsHKT1;5), which encodes a Na+‐selective transporter that maintains K+/Na+ homeostasis under salt stress. Furthermore, we showed that OsSDG721 binds to and deposits the H3K4me3 mark in the promoter and coding region of OsHKT1;5, thereby upregulating OsHKT1;5 expression under saline–alkaline stress. Overall, by generating Kitaake activation‐tagging pools, we established that the H3K4 methyltransferase OsSDG721 enhances saline–alkaline stress tolerance in rice.

A modified cry9Aa2 gene under the transcriptional control of the CaMV 35S promoter was transferred to four potato cultivars (‘Iwa’, ‘Karaka’, ‘Pacific’ and ‘Red Rascal’) using Agrobacterium-mediate...

Transcriptional regulation, a pivotal biological process by which cells adapt to environmental fluctuations, is achieved by the binding of transcription factors to target sequences in a sequence-specific manner. However, how transcription factors recognize the correct target from amongst the numerous candidates in a genome has not been fully elucidated. We here show that, in the fission-yeast fbp1 gene, when transcription factors bind to target sequences in close proximity, their binding is reciprocally stabilized, thereby integrating distinct signal transduction pathways. The fbp1 gene is massively induced upon glucose starvation by the activation of two transcription factors, Atf1 and Rst2, mediated via distinct signal transduction pathways. Atf1 and Rst2 bind to the upstream-activating sequence 1 region, carrying two binding sites located 45 bp apart. Their binding is reciprocally stabilized due to the close proximity of the two target sites, which destabilizes the independent binding of Atf1 or Rst2. Tup11/12 (Tup-family co-repressors) suppress independent binding. These data demonstrate a previously unappreciated mechanism by which two transcription-factor binding sites, in close proximity, integrate two independent-signal pathways, thereby behaving as a hub for signal integration.

Osmanthus fragrans is one of the top ten traditional flowers in China. It is divided into three different groups according to its color. α-Carotene and β-carotene are the main determinants to distinguish the color differences between three groups. However, the dominant genes and transcription factors involved in carotenoid metabolism remain unclear. CPTA treatment (0.7 mmol · L−1) remarkably promoted lycopene, α-carotene and β-carotene contents in flowers. Transcriptome sequencing analysis revealed that CPTA treatment could trigger chain reactions in carotenoid metabolism pathway genes. Four up-regulated and 10 down-regulated transcription factors which have close association with carotenoid variation were significantly induced by CPTA treatment. The up-regulated TFs such as MYB43, MYB123, HSF, were further subjected to transcript expression determination in different cultivars with drastic colors. Among them, transcript expression of four up-regulated TFs coincided with the carotenoid accumulation in different cultivars. We selected up-regulated OfMYB43 to verify its function, which is related to stress tolerance and transcriptional regulation. Transient overexpression of OfMYB43 in O. fragrans flowers showed that it could remarkably promote the expression of PDS, ZISO, LCYE and CCD4, leading to increased accumulation of β-branch carotenoids. OfMYB43 was a potential positive regulator of carotenoid biosynthesis in O. fragrans flowers. This study provides insight into the molecular mechanism of carotenoid metabolism in O. fragrans.

Myxoid liposarcoma (MLPS) is a rare soft-tissue sarcoma characterised by the expression of FUS-DDIT3 chimera. Trabectedin has shown significant clinical anti-tumour activity against MLPS. To characterise the molecular mechanism of trabectedin sensitivity and of resistance against it, we integrated genomic and transcriptomic data from treated mice bearing ML017 or ML017/ET, two patient-derived MLPS xenograft models, sensitive to and resistant against trabectedin, respectively. Longitudinal RNA-Seq analysis of ML017 showed that trabectedin acts mainly as a transcriptional regulator: 15 days after the third dose trabectedin modulates the transcription of 4883 genes involved in processes that sustain adipocyte differentiation. No such differences were observed in ML017/ET. Genomic analysis showed that prolonged treatment causes losses in 4p15.2, 4p16.3 and 17q21.3 cytobands leading to acquired-resistance against the drug. The results dissect the complex mechanism of action of trabectedin and provide the basis for novel combinatorial approaches for the treatment of MLPS that could overcome drug-resistance.

OsPR10a is one of the well known pathogenesis-related genes in rice, and is induced by multiple plant hormones and pathogens. However, the underlying transcriptional regulation mechanisms in response to different signals and their crosstalks are still largely unknown. In order to find new players participated in the activation of OsPR10a, we systematically analyzed the basal expression patterns as well as the expression responses of a 2.5 kb OsPR10a promoter in rice transgenic plants after phytohormone and pathogen stimulations. In agreement with the native gene expression, the OsPR10a promoter can drive glucuronidase (GUS) gene expressing in spots of leaf cells, leaf trichomes, lemmas and paleae, germinating embryos, calli and root tips. The leaf expression of OsPR10a::GUS was dramatically increased upon jasmonic acid (JA) and cytokinin (CK) treatments, or challenges of the pathogen Magnaporthe grisea and Xanthomonas oryzae pv. oryzae. Thus, the OsPR10a promoter reported here can faithfully reflect its native gene expression. The effects of several JA and CK responsive OsWRKY genes on the regulation of OsPR10a promoter were then inspected by luciferase transient expression assay, and the JA inducible OsWRKY10 transcription factor was found as a new positive regulator of OsPR10a. However, the key transcription factors of JA and CK signaling pathways, OsMYC2 and B-type response regulators, were not responsible for the activation of OsPR10a promoter. Our findings provided new insights into the regulation of OsPR10a expression during plant-hormone/pathogen interactions, and the OsPR10a reporter system can be useful to unravel novel regulators from both pathogen and host.

MADS-domain transcription factor RIPENING INHIBITOR (RIN) is the global regulator of tomato Solanum lycopersicum L. fruit ripening. RIN controls the cascade of fleshy fruit ripening reactions on several levels: it activates the expression of genes encoding other regulation proteins and genes of ethylene biosynthesis (initiation of ethylene-dependent signaling pathways); it directly activates transcription of genes of carotenoid biosynthesis, aroma compounds, carbohydrate metabolism and cell wall-modifying enzymes (by ethylene independent regulation); RIN also involved in epigenetic control of fleshy fruit ripening. Originally discovered in tomato, RIN homologs have now been described for many fleshy fruit crops. The review considers the molecular features of the RIN and homologues MADS-domain transcription factors in different plant species that have similar function of fleshy fruit ripening control and sharing the same evolutionary history. The structure, spatial-temporal expression, and target genes of these regulators are characterized. Using the example of monocotyledonous and dicotyledonous plants that form fleshy fruits, such as tomato, banana, pepper, grape, and strawberry, it has been shown that MADS proteins of the SEPALLATA subfamily play a central role in the complex transcriptional regulation of the ripening cascade of both climacteric and non-climacteric fruits.

Genetics studies the inheritance of genetic information encoded by the base pair sequence and its variants. Sequence variants can have severe consequences as seen in genetically inherited diseases (e. g. osteogenesis Imperfecta, hypophosphatasia). On the other hand, epigenetics deals with inherited and dynamically reversible modifications of chromatin without changing the base pair sequence, resulting in a change in phenotype without a change in genotype. These modifications primarily exert their effects by influencing gene expression. Initially, the definition of epigenetics exclusively comprised inherited changes that persist across several generations without changes in the DNA sequence. This definition has been extended to include also dynamic and partially reversible changes that occur more short-term. These gene modulatory effects introduce new levels of complexity and are crucial determinants of cell fate and organismal development. With its length of approximately two meters, human DNA has to be compacted to fit into the nuclei and fulfill its functions. DNA is wrapped around histone octamers into so-called nucleosomes. DNA, histones, and other DNA-associated proteins together form what is called chromatin. DNA packaging is achieved by variable degrees of chromatin condensation depending on cell type and context. Epigenetic transcriptional regulation modifies the affinity and accessibility of cis-regulatory elements (CREs) for transcription factors and the basic transcriptional machinery and governs interaction between CREs. CREs include promoters, enhancers, silencers, and insulators and are potent modulators of gene expression impacting core cell biological processes such as proliferation and differentiation. Chromatin looping and remodeling by differential covalent modifications of DNA (e. g., methylation or hydroxylation) and histone tails (e. g., acetylation or methylation) elicit fundamental changes in CRE accessibility, thus impacting gene expression. Chromatin looping depends on a specialized machinery including cohesins. Chromatin modifications are mediated by specific enzymes like DNA methylases (DNMTs), histone-modifying enzymes, like histone methyl- and acetyltransferases (KMTs, HATs/KATs), and histone demethylases and deacetylases (KDMs, HDACs). It becomes increasingly evident that epigenetic (dys)regulation plays a decisive role in physiology and pathophysiology, impacting many age-related diseases like cancer and degenerative pathologies (e. g., osteoporosis, Alzheimer’s, or Parkinson’s) in a significant fashion. Recently, small-molecule inhibitors of chromatin-modifying enzymes (e. g., vorinostat) have been identified and successfully introduced in therapy. Significant progress in high-throughput sequencing technologies and big data analysis has broadened our understanding of noncoding (nc) RNAs and DNA sequence regions in (post-)transcriptional regulation and disease development. Among ncRNAs that play vital roles in gene expression are micro- (miRs) and long noncoding RNAs (lncRNAs; e. g., XIST or HOTAIR). By interacting with the coding genome, these RNAs modulate important genetic programs. Interfering RNAs can, for example, enhance the post-transcriptional degradation of transcripts, altering their translation, or assist in the recruitment of chromatin-modifying enzymes to regulate transcription. They can also be packaged into extracellular vesicles as cargo and thus deliver critical information to the microenvironment or even systemically to distant tissues. Therefore, ncRNAs represent a novel playground for therapeutical investigations and supplement epigenetic mechanisms of gene regulation while being subject to epigenetic regulation themselves. Last but not least, dysregulated ncRNAs can also propagate disease. Until recently, the detection of epigenetic phenomena necessitated invasive diagnostic interventions. However, with the arrival of so-called “liquid biopsies” an analysis of circulating cell-free DNA fragments (cfDNA) and RNAs as well as vesicle-packed RNAs through minimal invasively drawn blood samples can be obtained. Such “fragmentomics” and RNAomics approaches on peripheral blood will ultimately serve as diagnostic tools for personalized clinical interventions.

We hypothesized that there were diurnal differences in metabolism, with major transcriptional changes occurring early during the day and/or night between migratory and non-migratory states of avian migrants. Present study investigated this in captive Black-headed Buntings (Emberiza melanocephala) exhibiting long-day stimulated vernal migratory and post-breeding non-migratory states, by using RNA-Seq and qPCR assays of liver samples collected at 1 h into day (hour 1) and 1 h into night (hour 17) of the 16-h photoperiod (16L:8D). There were differentially expressed genes (DEGs) both within (day vs. night) and between (vernal migratory vs. non-migratory) states. Within the state, 358 and 52 DEGs were identified in migratory and non-migratory states, respectively. In the migratory state, genes associated with oxidative phosphorylation (sdh) had higher expression, and genes associated with fat metabolism (acaca and elovl6) and ABC transporters (abcg5, abcg8) had lower expression at night, compared to the daytime. In the non-migratory state, among genes associated with fat metabolism and gluconeogenesis, ppara and hmgcl had higher while aacs had lower expression at night. Between states, 35 and 180 DEGs were identified in day and night, respectively, with highly expressed genes associated with fat metabolism (acsbg2, cetp) found in migratory, and those associated with cell death (casp7), gluconeogenesis (stat3) and circadian rhythm pathway (cry1) in the non-migratory state. These results demonstrate differentially activated hepatic molecular pathways during photostimulated vernal migratory and post-breeding non-migratory states of buntings and provide molecular insights into differential metabolic support to physiologically contrasting seasonal life-history states in migratory songbirds.

Trichomes are hair-like structures that are essential for abiotic and biotic stress responses. Tomato Hair (H), encoding a C2H2 zinc finger protein, was found to regulate the multicellular trichomes on stems. Here, we characterized Solyc10g078990 (hereafter Hair2, H2), its closest homolog, to examine whether it was involved in trichome development. The H2 gene was highly expressed in the leaves, and its protein contained a single C2H2 domain and was localized to the nucleus. The number and length of type I trichomes on the leaves and stems of knock-out h2 plants were reduced when compared to the wild-type, while overexpression increased their number and length. An auto-activation test with various truncated forms of H2 using yeast two-hybrid (Y2H) suggested that H2 acts as a transcriptional regulator or co-activator and that its N-terminal region is important for auto-activation. Y2H and pull-down analyses showed that H2 interacts with Woolly (Wo), which regulates the development of type I trichomes in tomato. Luciferase complementation imaging assays confirmed that they had direct interactions, implying that H2 and Wo function together to regulate the development of trichomes. These results suggest that H2 has a role in the initiation and elongation of type I trichomes in tomato.

The photosynthetic capacity of mature leaves increases after several days' exposure to constant or intermittent episodes of high light (HL) and is manifested primarily as changes in chloroplast physiology. How this chloroplast-level acclimation to HL is initiated and controlled is unknown. From expanded Arabidopsis leaves, we determined HL-dependent changes in transcript abundance of 3844 genes in a 0-6 h time-series transcriptomics experiment. It was hypothesized that among such genes were those that contribute to the initiation of HL acclimation. By focusing on differentially expressed transcription (co-)factor genes and applying dynamic statistical modelling to the temporal transcriptomics data, a regulatory network of 47 predominantly photoreceptor-regulated transcription (co-)factor genes was inferred. The most connected gene in this network was B-BOX DOMAIN CONTAINING PROTEIN32 (BBX32). Plants overexpressing BBX32 were strongly impaired in acclimation to HL and displayed perturbed expression of photosynthesis-associated genes under LL and after exposure to HL. These observations led to demonstrating that as well as regulation of chloroplast-level acclimation by BBX32, CRYPTOCHROME1, LONG HYPOCOTYL5, CONSTITUTIVELY PHOTOMORPHOGENIC1 and SUPPRESSOR OF PHYA-105 are important. In addition, the BBX32-centric gene regulatory network provides a view of the transcriptional control of acclimation in mature leaves distinct from other photoreceptor-regulated processes, such as seedling photomorphogenesis.

BackgroundSpatial interactions and insulation of chromatin regions are associated with transcriptional regulation. Domains of frequent chromatin contacts are proposed as functional units, favoring and delimiting gene regulatory interactions. However, contrasting evidence supports the association between chromatin domains and transcription.ResultHere, we assess gene co-regulation in chromatin domains across multiple human cancers, which exhibit great transcriptional heterogeneity. Across all datasets, gene co-regulation is observed only within a small yet significant number of chromatin domains. We design an algorithmic approach to identify differentially active domains (DADo) between two conditions and show that these provide complementary information to differentially expressed genes. Domains comprising co-regulated genes are enriched in the less active B sub-compartments and for genes with similar function. Notably, differential activation of chromatin domains is not associated with major changes of domain boundaries, but rather with changes of sub-compartments and intra-domain contacts.ConclusionOverall, gene co-regulation is observed only in a minority of chromatin domains, whose systematic identification will help unravel the relationship between chromatin structure and transcription.

Transcriptional regulation by Wnt signalling is primarily thought to be accomplished by a complex of β-catenin and TCF family transcription factors (TFs). Although numerous studies have suggested that additional TFs play roles in regulating Wnt target genes, their mechanisms of action have not been investigated in detail. We characterised a Wnt-responsive element (WRE) downstream of the Wnt target geneAxin2and found that TCFs and Caudal-related homeodomain (CDX) proteins were required for its activation. Using a new separation-of-function TCF mutant, we found that WRE activity requires the formation of a TCF/CDX complex. Our systematic mutagenesis of this enhancer identified other sequences essential for activation by Wnt signalling, including several copies of a novel CAG DNA motif. Computational and experimental evidence indicates that the TCF/CDX/CAG mode of regulation is prevalent in multiple WREs. Put together, our results demonstrate the complex nature of cis- and trans- interactions required for signal-dependent enhancer activity.