Project description:The histone variant H2A.Z is one of the most evolutionally conserved histone variants. In vertebrates, two isoforms, H2A.Z.1 and H2A.Z.2, are identified and are involved in multiple epigenetic regulations. However, the role of H2A.Z in epigenetic regulations largely remains unknown especially in vertebrate. Previously, we derived tetracycline-inducible H2A.Z isofmrs double knockout (DKO) cells by using DT40 cells. With this cell, we showed that H2A.Z DKO leads to defects in mitotic progression and gene expression. To elucidate the function of H2A.Z further, we established genetic complementation system and confirmed that introducing exogenous H2A.Z complemented phenotypes of H2A.Z DKO cells. Given that acetylation of the N-terminal tail of H2A.Z reportedly contributes to significant roles in H2A.Z functions, we introduced two types of H2A.Z mutants, non-acetylable H2A.Z (5KR-H2A.Z) and chimeric H2A.Z in which its N-terminal tail is replaced with that of canonical H2A (H2A-H2A.Z), into H2A.Z DKO cells. These H2A.Z mutants complemented defects in mitotic progression. However, significant transcriptional dysregulation was observed in H2A.Z DKO cells stably expressing 5KR-H2A.Z and H2A-H2A.Z. These results suggest that the core domain and the N-terminal tail of the vertebrate H2A.Z contribute individually to mitotic progression and transcription regulation, respectively.
Project description:To investigate the functional conservation of H2A.Z histones during eukaryotic evolution we transformed h2a.z deficient plants with three human H2A.Z proteins to assess their ability to rescue the mutant defects. We discovered that human H2A.Z.1 and H2A.Z.2.1 fully complement the phenotypic abnormalities of h2a.z plants even though Arabidopsis and human H2A.Z N-terminal tail sequences are divergent, while the brain-specific splice variant H2A.Z.2.2 has a dominant-negative effect in wild-type plants. Furthermore, H2A.Z.1 almost completely re-establishes normal H2A.Z chromatin occupancy in h2a.z plants and restores the expression of more than 84 % of misexpressed genes. Finally, our hypothesis that the N-terminal tail of Arabidopsis H2A.Z is not crucial for its overall function was supported by the ability of N-terminal end truncations of Arabidopsis HTA11 to largely rescue the defects of h2a.z mutants.
Project description:To investigate the functional conservation of H2A.Z histones during eukaryotic evolution we transformed h2a.z deficient plants with three human H2A.Z proteins to assess their ability to rescue the mutant defects. We discovered that human H2A.Z.1 and H2A.Z.2.1 fully complement the phenotypic abnormalities of h2a.z plants even though Arabidopsis and human H2A.Z N-terminal tail sequences are divergent, while the brain-specific splice variant H2A.Z.2.2 has a dominant-negative effect in wild-type plants. Furthermore, H2A.Z.1 almost completely re-establishes normal H2A.Z chromatin occupancy in h2a.z plants and restores the expression of more than 84 % of misexpressed genes. Finally, our hypothesis that the N-terminal tail of Arabidopsis H2A.Z is not crucial for its overall function was supported by the ability of N-terminal end truncations of Arabidopsis HTA11 to largely rescue the defects of h2a.z mutants.
Project description:To investigate the functional conservation of H2A.Z histones during eukaryotic evolution we transformed h2a.z deficient plants with three human H2A.Z proteins to assess their ability to rescue the mutant defects. We discovered that human H2A.Z.1 and H2A.Z.2.1 fully complement the phenotypic abnormalities of h2a.z plants even though Arabidopsis and human H2A.Z N-terminal tail sequences are divergent, while the brain-specific splice variant H2A.Z.2.2 has a dominant-negative effect in wild-type plants. Furthermore, H2A.Z.1 almost completely re-establishes normal H2A.Z chromatin occupancy in h2a.z plants and restores the expression of more than 84 % of misexpressed genes. Finally, our hypothesis that the N-terminal tail of Arabidopsis H2A.Z is not crucial for its overall function was supported by the ability of N-terminal end truncations of Arabidopsis HTA11 to largely rescue the defects of h2a.z mutants.
Project description:H2A.Z-nucleosomes participate in both euchromatin and heterochromatin and it has proven difficult to reveal how the disparate roles and stability features imparted by H2A.Z are connected. Using an in situ assay of nucleosome stability in nuclei of DT40 cells expressing engineered forms of the variant we show that H2A.Z is released from nucleosomes of peripheral heterochromatin at unusually high salt concentrations, compared to cells expressing C-terminally truncated H2A.Z. Binding of the tail-peptide (C9) to reconstituted nucleosomes, DNA and the nuclear lamina were detected. Upon treatment of HeLa nuclei with C9, the H2A.Z-nucleosomes assumed canonical stability, the peripheral heterochromatin became dispersed and overall nuclease sensitivity increased, recapitulating tail-dependent differences in DT40. When introduced into live cells, C9 elicited chromatin reorganization and transcriptional down-regulation of ~600 genes. Thus, large-scale epigenetic modulation can be achieved by targeting or making advantage of molecular interactions involving the C-terminal tail of H2A.Z.
2023-02-23 | GSE225680 | GEO
Project description:EPIGENETIC MODULATION USING A PEPTIDE OF THE C-TERMINAL UNSTRUCTURED TAIL OF H2A.Z.
Project description:The involvement of the histone variant H2A.Z and its isoforms in the regulation of gene expression is an increasing exciting field considering the impact of such regulations in physio-pathology. Indeed, we and other recently showed that H2A.Z.1 and H2A.Z.2 isoforms exert cooperative or antagonistic transcriptional regulations on subsets of genes involved in key processes, such as proliferation, senescence or several organ functions. In this work, we analyze the relative role of both H2A.Z isoforms on parameters of the intestinal epithelial homeostasis. We observed that the amount of H2A.Z.1 and H2A.Z.2 at TSS and gene bodies are highly correlated and that the two H2A.Z isoforms can replace each other when depleted. We highlighted the role of their respective deposition onto chromatin by specific incorporators in some discrete isoform-specific contribution to the differentiation process. We have also uncovered an unexpected link between H2A.Z isoforms occupancy at gene bodies and the propensity of genes to be induced in enterocyte differentiation.
Project description:The involvement of the histone variant H2A.Z and its isoforms in the regulation of gene expression is an increasing exciting field considering the impact of such regulations in physio-pathology. Indeed, we and other recently showed that H2A.Z.1 and H2A.Z.2 isoforms exert cooperative or antagonistic transcriptional regulations on subsets of genes involved in key processes, such as proliferation, senescence or several organ functions. In this work, we analyze the relative role of both H2A.Z isoforms on parameters of the intestinal epithelial homeostasis. We observed that the amount of H2A.Z.1 and H2A.Z.2 at TSS and gene bodies are highly correlated and that the two H2A.Z isoforms can replace each other when depleted. We highlighted the role of their respective deposition onto chromatin by specific incorporators in some discrete isoform-specific contribution to the differentiation process. We have also uncovered an unexpected link between H2A.Z isoforms occupancy at gene bodies and the propensity of genes to be induced in enterocyte differentiation.
Project description:The histone variant H2A.Z is a hallmark of nucleosomes flanking the promoters of protein coding genes, and is often found in nucleosomes that also carry lysine 56- acetylated histone H3 (H3-K56Ac), a mark which promotes rapid replication- independent turnover of nucleosomes. Although H2A.Z and H3-K56Ac have been generally implicated in transcriptional activation, their exact contributions have remained elusive. Here we find that H3-K56Ac promotes RNA polymerase II occupancy at a large number of protein coding and noncoding loci, yet neither H3- K56Ac nor H2A.Z has a significant impact on steady state mRNA levels in yeast. Instead, broad effects of H3-K56Ac or H2A.Z on levels of both coding and noncoding RNAs (ncRNAs) are only revealed in the absence of the nuclear RNA exosome. H2A.Z is also necessary for expression of divergent, promoter-proximal ncRNAs in mouse embryonic stem cells, suggesting a conserved role for H2A.Z across eukaryotes. Finally, we show that H2A.Z functions with H3-K56Ac in chromosome folding, facilitating formation of chromosome interaction domains (CIDs). Our study suggests that H2A.Z and H3-K56Ac work in concert with the RNA exosome to control mRNA and ncRNA expression, perhaps in part by regulating higher order chromatin structures. 2 replicates of WT (CY1089), rtt109â (CY2210), rrp6â (CY2071) and one replicate of the W303 input (Sample 7). TableS5.xlsx contains the processed IP/input values for each ORF transcript.