Integrated analysis of H2A.Z isoforms reveals a complex interplay in gene regulation [U2OS_siZ1-siZ2 RNA-seq]
Ontology highlight
ABSTRACT: The H2A.Z histone variant plays major roles in the control of gene expression. In human, H2A.Z is encoded by two genes expressing two isoforms, H2A.Z.1 and H2A.Z.2 differing by three amino acids. Here, we undertook an integrated analysis of the independent and interdependent functions of these two isoforms in gene expression using endogenously-tagged isoform. RNA-Seq analysis following depletion of either isoform or both together in untransformed cells showed that they can regulate both distinct and overlapping sets of genes positively or negatively in a context-dependent manner. Our data revealed that the two isoforms have similar or antagonistic function depending on the gene. H2A.Z.1 and H2A.Z.2 can replace each other at Transcription Start Sites, providing a molecular explanation for this interplay. Mass spectrometry analysis showed that H2A.Z.1 and H2A.Z.2 have specific interactors, PHF14 and associated proteins for H2A.Z.1 and the histone deacetylase SIRT1 for H2A.Z.2. Moreover, we show that PHF14 and SIRT1 mediate the functional antagonism between H2A.Z.1 and H2A.Z.2. In conclusion, we propose a model in which the balance between H2A.Z.1 and H2A.Z.2 at promoters is critically important to regulate specific gene expression and depends on the recruitment of specific proteins. Our work thus provides an additional layer of complexity to the control of gene expression by histone variants.
Project description:The H2A.Z histone variant plays major roles in the control of gene expression. In human, H2A.Z is encoded by two genes expressing two isoforms, H2A.Z.1 and H2A.Z.2 differing by three amino acids. Here, we undertook an integrated analysis of the independent and interdependent functions of these two isoforms in gene expression using endogenously-tagged isoform. RNA-Seq analysis following depletion of either isoform or both together in untransformed cells showed that they can regulate both distinct and overlapping sets of genes positively or negatively in a context-dependent manner. Our data revealed that the two isoforms have similar or antagonistic function depending on the gene. H2A.Z.1 and H2A.Z.2 can replace each other at Transcription Start Sites, providing a molecular explanation for this interplay. Mass spectrometry analysis showed that H2A.Z.1 and H2A.Z.2 have specific interactors, PHF14 and associated proteins for H2A.Z.1 and the histone deacetylase SIRT1 for H2A.Z.2. Moreover, we show that PHF14 and SIRT1 mediate the functional antagonism between H2A.Z.1 and H2A.Z.2. In conclusion, we propose a model in which the balance between H2A.Z.1 and H2A.Z.2 at promoters is critically important to regulate specific gene expression and depends on the recruitment of specific proteins. Our work thus provides an additional layer of complexity to the control of gene expression by histone variants.
Project description:The H2A.Z histone variant plays major roles in the control of gene expression. In human, H2A.Z is encoded by two genes expressing two isoforms, H2A.Z.1 and H2A.Z.2 differing by three amino acids. Here, we undertook an integrated analysis of the independent and interdependent functions of these two isoforms in gene expression using endogenously-tagged isoform. RNA-Seq analysis following depletion of either isoform or both together in untransformed cells showed that they can regulate both distinct and overlapping sets of genes positively or negatively in a context-dependent manner. Our data revealed that the two isoforms have similar or antagonistic function depending on the gene. H2A.Z.1 and H2A.Z.2 can replace each other at Transcription Start Sites, providing a molecular explanation for this interplay. Mass spectrometry analysis showed that H2A.Z.1 and H2A.Z.2 have specific interactors, PHF14 and associated proteins for H2A.Z.1 and the histone deacetylase SIRT1 for H2A.Z.2. Moreover, we show that PHF14 and SIRT1 mediate the functional antagonism between H2A.Z.1 and H2A.Z.2. In conclusion, we propose a model in which the balance between H2A.Z.1 and H2A.Z.2 at promoters is critically important to regulate specific gene expression and depends on the recruitment of specific proteins. Our work thus provides an additional layer of complexity to the control of gene expression by histone variants.
Project description:The H2A.Z histone variant plays major roles in the control of gene expression. In human, H2A.Z is encoded by two genes expressing two isoforms, H2A.Z.1 and H2A.Z.2 differing by three amino acids. Here, we undertook an integrated analysis of the independent and interdependent functions of these two isoforms in gene expression using endogenously-tagged isoform. RNA-Seq analysis following depletion of either isoform or both together in untransformed cells showed that they can regulate both distinct and overlapping sets of genes positively or negatively in a context-dependent manner. Our data revealed that the two isoforms have similar or antagonistic function depending on the gene. H2A.Z.1 and H2A.Z.2 can replace each other at Transcription Start Sites, providing a molecular explanation for this interplay. Mass spectrometry analysis showed that H2A.Z.1 and H2A.Z.2 have specific interactors, PHF14 and associated proteins for H2A.Z.1 and the histone deacetylase SIRT1 for H2A.Z.2. Moreover, we show that PHF14 and SIRT1 mediate the functional antagonism between H2A.Z.1 and H2A.Z.2. In conclusion, we propose a model in which the balance between H2A.Z.1 and H2A.Z.2 at promoters is critically important to regulate specific gene expression and depends on the recruitment of specific proteins. Our work thus provides an additional layer of complexity to the control of gene expression by histone variants.
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:Pancreatic ductal adenocarcinoma is one of the most intractable and devastating of all malignant tumors. Epigenetic modifications involving both DNA methylation and histone modification have a relationship between tumor initiation and progression. However, the contribution of histone variants in the PDAC is unknown. Here, we demonstrated that the histone variant H2A.Z is highly expressed in PDAC cell lines and PDAC patients and its overexpression correlated with poor prognosis. We found that the three-histone H2A.Z isoforms (H2A.Z.1, H2A.Z.2.1 and, H2A.Z.2.2), are highly expressed in PDAC cell lines and PDAC patients. Knockdown of three H2A.Z isoforms induces a senescent phenotype, cell cycle arrest in phase G2/M, increased cyclin-dependent kinase inhibitor CDKN2A/p16, SA-β-galactosidase activity and interleukin 8 production in PDAC. Transcriptome analysis of knockdown of the H2A.Z isoforms showed altered gene expression in the fatty acid biosynthesis. As well as in the genes that control the cell cycle and DNA damage repair. Furthermore, H2A.Z isoform deficiency, reduces the tumor size in a mouse xenograft model in vivo, and sensitizes PDAC cells to gemcitabine. These results make H2A.Z a potential candidate as a diagnostic biomarker and therapeutic target for PDAC
Project description:The histone variant H2A.Z plays important functions in the regulation of gene expression. In mammals, it is encoded by two genes, giving rise to two highly related isoforms named H2A.Z.1 and H2A.Z.2, which can have similar or antagonistic functions depending on the promoter. Knowledge of the physiopathological consequences of such functions emerges, but how the balance between these isoforms regulates tissue homeostasis is not fully understood. Here, we investigated the relative role of H2A.Z isoforms in intestinal epithelial homeostasis. Through genome-wide analysis of H2A.Z genomic localization in differentiating Caco-2 cells, we uncovered an enrichment of H2A.Z isoforms on the bodies of genes which are induced during enterocyte differentiation, stressing the potential importance of H2A.Z isoforms dynamics in this process. Through a combination of in vitro and in vivo experiments, we further demonstrated the two isoforms cooperate for stem and progenitor cells proliferation, as well as for secretory lineage differentiation. However, we found that they antagonistically regulate enterocyte differentiation, with H2A.Z.1 preventing terminal differentiation and H2A.Z.2 favoring it. Altogether, these data indicate that H2A.Z isoforms are critical regulators of intestine homeostasis and may provide a paradigm of how the balance between two isoforms of the same chromatin structural protein can control physiopathological processes.
Project description:Histone acetylation and deposition of H2A.Z variant are integral aspects of active transcrip-tion. In Drosophila, the single DOMINO chromatin regulator complex is thought to combine both activities via an unknown mechanism. Here we show that alternative isoforms of the DOMINO nucleosome remodeling ATPase, DOM-A and DOM-B, directly specify two distinct multi-subunit complexes. Both complexes are necessary for transcriptional regulation but through different mechanisms. The DOM-B complex incorporates H2A.V (the fly ortholog of H2A.Z) genome-wide in an ATP-dependent manner, like the yeast SWR1 complex. The DOM-A complex, instead, functions as an ATP-independent histone acetyltransferase com-plex similar to the yeast NuA4, targeting lysine 12 of histone H4. Our work provides an in-structive example of how different evolutionary strategies lead to similar functional separation. In yeast and humans, nucleosome remodeling and histone acetyltransferase complexes orig-inate from gene duplication and paralog specification. Drosophila generates the same diversi-ty by alternative splicing of a single gene.
Project description:Creating long-lasting memories relies on learning-induced changes in gene expression, which are regulated by epigenetic modifications of DNA and associated histone proteins. Post-translational modifications (PTMs) of histone proteins are key regulators of transcription, with different PTMs producing unique effects on gene activity and behavior. Although recent studies began to investigate histone variants as key regulators of memory formation, PTMs are rarely considered in relation to their function. Here, we analyze the role of acetylation of histone variant H2A.Z.1 in memory and gene expression. To this end, we developed AAV constructs to overexpress mutated H2A.Z.1 isoforms that either mimic acetylation (acetyl-mimetic) by replacing lysines 4, 7 and 11 with glutamine (KQ), or that have impaired acetylation (acetyl-defective) by replacing the same lysine with alanine (KA). We found that overexpression of the acetyl-mimetic (H2A.Z.1KQ) or the acetyl-defective (H2A.Z.1KA) isoforms of H2A.Z.1 in the hippocampus produces different effects on memory depending on strength of the task and sex, with H2A.Z.1KQ generally having a beneficial effect on memory, while H2A.Z.1KA results in impaired memory. We further analyzed gene expression data and found that H2A.Z.1KQ and H2A.Z.1KA uniquely impact the expression of different classes of genes in females and males. However, different genes are regulated by different isoforms in the 2 sexes. Finally, we describe, for the first time, that H2A.Z is involved in the alternative splicing of neuronal genes. Notably, H2A.Z depletion and its replacement with different isoforms influence transcription and splicing of different genes, suggesting that H2A.Z.1 can regulate genes through splicing and expression levels. This is the first study demonstrating that direct manipulation of the levels of AcH2A.Z regulates memory, gene expression and splicing. Overall, this study adds another layer of complexity to the contribution of histone variants to higher brain functions, consolidating H2A.Z as a key regulator of memory.
Project description:Creating long-lasting memories relies on learning-induced changes in gene expression, which are regulated by epigenetic modifications of DNA and associated histone proteins. Post-translational modifications (PTMs) of histone proteins are key regulators of transcription, with different PTMs producing unique effects on gene activity and behavior. Although recent studies began to investigate histone variants as key regulators of memory formation, PTMs are rarely considered in relation to their function. Here, we analyze the role of acetylation of histone variant H2A.Z.1 in memory and gene expression. To this end, we developed AAV constructs to overexpress mutated H2A.Z.1 isoforms that either mimic acetylation (acetyl-mimetic) by replacing lysines 4, 7 and 11 with glutamine (KQ), or that have impaired acetylation (acetyl-defective) by replacing the same lysine with alanine (KA). We found that overexpression of the acetyl-mimetic (H2A.Z.1KQ) or the acetyl-defective (H2A.Z.1KA) isoforms of H2A.Z.1 in the hippocampus produces different effects on memory depending on strength of the task and sex, with H2A.Z.1KQ generally having a beneficial effect on memory, while H2A.Z.1KA results in impaired memory. We further analyzed gene expression data and found that H2A.Z.1KQ and H2A.Z.1KA uniquely impact the expression of different classes of genes in females and males. However, different genes are regulated by different isoforms in the 2 sexes. Finally, we describe, for the first time, that H2A.Z is involved in the alternative splicing of neuronal genes. Notably, H2A.Z depletion and its replacement with different isoforms influence transcription and splicing of different genes, suggesting that H2A.Z.1 can regulate genes through splicing and expression levels. This is the first study demonstrating that direct manipulation of the levels of AcH2A.Z regulates memory, gene expression and splicing. Overall, this study adds another layer of complexity to the contribution of histone variants to higher brain functions, consolidating H2A.Z as a key regulator of memory.