Transcriptome profiling reveals a novel role for Trichostatin A in antagonizing histone chaperone Chz1 mediated telomere anti-silencing.
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE30228 | GEO | 2011/06/28
SECONDARY ACCESSION(S): PRJNA143987
REPOSITORIES: GEO
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Project description:The histone chaperones play an important role in chromatin assembly and disassembly during replication and transcription. We assessed the global roles of histone chaperones in Saccharomyces cerevisiae. Microarray transcriptional analyses indicate that histone chaperones have their own specific target genes, and various histone chaperones have partially overlapping functions during transcriptional regulation. Histone deacetylase inhibitor TSA and histone chaperones Asf1, Vps75 and Rtt106 can function in parallel pathways to regulate transcription. Moreover, TSA can specifically antagonize histone chaperone Chz1-mediated telomere anti-silencing. This study demonstrates that a mutual cross-talk mechanism exists between histone chaperones and histone deacetylation in transcriptional regulation. All yeast strains used in this study are listed in the paper (Table S1). CHZ1, NAP1, ASF1, VPS75 and RTT106 genes were deleted individually by homologous recombination in BY4742 (WT) by using a previously described in (Wan, Y. et al. MCB, 2009) PCR-based procedure. The strains were cultured at 30°C in YPD (1% yeast extract, 2% peptone, 2% glucose) media. For TSA treatments, WT and deletion mutants were grown to mid-log phase (OD600=0.5), TSA (Sigma-Aldrich) was then added to the yeast cultures at a final concentration of 10 ?M and cells were cultured for additional hour.Total RNA was isolated by hot acid phenol extraction protocol as previously described in Wan, Y. et al. MCB, 2009. Microarray labeling and hybridization reactions were performed as previously described in Wan, Y. et al. MCB, 2009 and Wan, Y. et al. NAR, 2010. Two color microarrays, comparing RNA from the experimental conditions (deletion mutations grown in YPD, WT and deletion mutations grown in YPD with TSA treatment) to RNA from the control WT cells grown in glucose-containing medium (YPD), were performed using Agilent whole-genome S. cerevisiae arrays.
2011-06-28 | E-GEOD-30228 | biostudies-arrayexpress
Project description:A two-colour cell array screen reveals interdependent roles for histone chaperones and a chromatin boundary regulator in histone gene repression. We describe a fluorescent reporter system that exploits the functional genomic tools available in budding yeast to systematically assess consequences of genetic perturbations on gene expression. We used our Reporter-Synthetic Genetic Array (R-SGA) method to screen for regulators of core histone gene expression. We discovered that the histone chaperone Rtt106 functions in a pathway with two other chaperones, Asf1 and the HIR complex, to create a repressive chromatin structure at core histone promoters. We found that activation of histone (HTA1) gene expression involves both relief of Rtt106-mediated repression by the activity of the histone acetyltransferase Rtt109 and restriction of Rtt106 to the promoter region by the bromodomain-containing protein Yta7. We propose that the maintenance of Asf1/HIR/Rtt106-mediated repressive chromatin domains is the primary mechanism of cell cycle regulation of histone promoters. Our data suggest that this pathway may represent a chromatin regulatory mechanism that is broadly used across the genome.
2009-08-14 | GSE16693 | GEO
Project description:The histone acetyltransferase Sas2 is part of the SAS-I complex and acetylates lysine 16 of histone H4 (H4 K16Ac) in the genome of Saccharomyces cerevisiae. Sas2-mediated H4 K16Ac is strongest over the coding region of genes with low expression. However, it is unclear how Sas2-mediated acetylation is incorporated into chromatin. Our previous work has shown physical interactions of SAS with the histone chaperones CAF-I and Asf1, suggesting a link between SAS-I mediated acetylation and chromatin assembly. Here, we find that Sas2-dependent H4 K16Ac in bulk histones requires passage of the cells through the S-phase of the cell cycle, and the rate of increase in H4 K16Ac depends on both CAF-I and Asf1, whereas steady-state levels and genome-wide distribution of H4 K16Ac shows only mild changes in their absence. Furthermore, H4 K16Ac is deposited in chromatin at genes upon repression, and this deposition requires the histone chaperone Spt6, but not CAF-I, Asf1, HIR or Rtt106. Altogether, our data indicate that Spt6 controls H4 K16Ac levels by incorporating K16-unacetylated H4 in strongly transcribed genes. Upon repression, Spt6 association is decreased, resulting in less deposition of K16-unacetylated and therefore in a concomitant increase of H4 K16Ac that is recycled during transcription.
2015-09-14 | E-MTAB-2638 | biostudies-arrayexpress
Project description:Histone chaperones and chromatin remodelers control nucleosome dynamics, essential for transcription, replication, and DNA repair. The histone chaperone Anti-Silencing Factor 1 (ASF1) plays a central role in facilitating CAF-1-mediated replication-dependent H3.1 deposition and HIRA-mediated replication-independent H3.3 deposition in yeast and metazoans. Whether ASF1 function is evolutionarily conserved in plants is unknown. Here, we show that Arabidopsis ASF1 proteins display an exclusive preference for the H3.3-depositing HIRA complex. Simultaneous mutation of both Arabidopsis ASF1 genes caused a decrease in chromatin density and ectopic H3.1 occupancy at loci typically enriched with H3.3. Genetic, transcriptomic, and proteomic data indicate that ASF1 proteins strongly prefer the HIRA complex over CAF-1. asf1 mutants also displayed an increase in spurious Pol II transcriptional initiation, and showed defects in the maintenance of gene body CG DNA methylation and in the distribution of histone modifications. Furthermore, ectopic targeting of ASF1 caused excessive histone deposition, less accessible chromatin, and gene silencing. These findings reveal the importance of ASF1-mediated H3.3-H4 deposition via the HIRA pathway for proper epigenetic regulation of the genome.
2022-10-31 | PXD035578 | Pride
Project description:The disruption of chromatin structure can result in transcription initiation from cryptic promoters within gene bodies. While the passage of RNA polymerase II is a well-characterized chromatin-disrupting force, numerous factors, including histone chaperones, normally stabilize chromatin on transcribed genes, thereby repressing cryptic transcription. DNA replication, which requires a partially overlapping set of histone chaperones, is also inherently disruptive to chromatin, but a role for DNA replication in cryptic transcription has never been examined. In this study, we tested the hypothesis that, in the absence of chromatin-stabilizing factors, DNA replication can promote cryptic transcription in S. cerevisiae. Using a novel fluorescent reporter assay, we show that multiple factors, including Asf1, CAF-1, Rtt106, Spt6, and FACT, block transcription from a cryptic promoter, but are entirely or partially dispensable in G1-arrested cells, suggesting a requirement for DNA replication in chromatin disruption. Collectively, these results demonstrate that transcription fidelity is dependent on numerous factors that function to assemble chromatin on nascent DNA.
2023-12-07 | GSE249580 | GEO
Project description:The disruption of chromatin structure can result in transcription initiation from cryptic promoters within gene bodies. While the passage of RNA polymerase II is a well-characterized chromatin-disrupting force, numerous factors, including histone chaperones, normally stabilize chromatin on transcribed genes, thereby repressing cryptic transcription. DNA replication, which requires a partially overlapping set of histone chaperones, is also inherently disruptive to chromatin, but a role for DNA replication in cryptic transcription has never been examined. In this study, we tested the hypothesis that, in the absence of chromatin-stabilizing factors, DNA replication can promote cryptic transcription in S. cerevisiae. Using a novel fluorescent reporter assay, we show that multiple factors, including Asf1, CAF-1, Rtt106, Spt6, and FACT, block transcription from a cryptic promoter, but are entirely or partially dispensable in G1-arrested cells, suggesting a requirement for DNA replication in chromatin disruption. Collectively, these results demonstrate that transcription fidelity is dependent on numerous factors that function to assemble chromatin on nascent DNA.
2023-12-06 | GSE249469 | GEO
Project description:Histone chaperones and chromatin remodelers control nucleosome dynamics, which are essential for transcription, replication, and DNA repair. The histone chaperone Anti-Silencing Factor 1 (ASF1) plays a central role in facilitating CAF-1-mediated replication-dependent H3.1 deposition and HIRA-mediated replication-independent H3.3 deposition in yeast and metazoans. Whether ASF1 function is evolutionarily conserved in plants is unknown. Here, we show that Arabidopsis ASF1 proteins display a preference for the HIRA complex. Simultaneous mutation of both Arabidopsis ASF1 genes caused a decrease in chromatin density and ectopic H3.1 occupancy at loci typically enriched with H3.3. Genetic, transcriptomic, and proteomic data indicate that ASF1 proteins strongly prefers the HIRA complex over CAF-1. asf1 mutants also displayed an increase in spurious Pol II transcriptional initiation and showed defects in the maintenance of gene body CG DNA methylation and in the distribution of histone modifications. Furthermore, ectopic targeting of ASF1 caused excessive histone deposition, less accessible chromatin, and gene silencing. These findings reveal the importance of ASF1-mediated histone deposition for proper epigenetic regulation of the genome.
2022-10-27 | GSE188493 | GEO
Project description:Histones are the protein components of the basic unit of chromatin, the core particle of the nucleosome. They play a central role in defining chromatin states associated with distinct cell fates and are classified into replicative and non-replicative/replacement histone variants. While the latter do not exhibit S phase regulation in their expression, the replicative histone variants show a major peak in expression early during S phase to support chromatin assembly during replication of the genome. Their expression is tightly regulated during the cell-cycle both transcriptionally and post-transcriptionally and involves a number of actors. During replication in human cells, two main chaperones ensure the deposition of H3-H4 onto DNA: Chromatin assembly factor 1 (CAF-1) and Anti-silencing factor 1 (ASF1). Interestingly, on the one hand, ASF1 binds the newly synthesized replicative histones H3.1/H3.2-H4 to hand them off to the downstream chaperone, CAF-1, for deposition onto the duplicated DNA strands in a DNA synthesis-coupled (DSC) manner. On the other hand, ASF1 also promotes the recycling of parental histones during replication. In addition, ASF1 binds the non-replicative variant H3.3 and hands it off to the downstream chaperone Histone regulator A (HIRA) for deposition of H3.3 in a DNA synthesis independent (DSI) manner. Finally, in human cells, ASF1 but not CAF-1, also provides a buffering system for histone excess generated in response to stalled replication, indicating yet another role for ASF1 in regulating the flow of replicative histones in higher eukaryotes. However, to date, roles of these chaperones in histone RNA metabolism in mammals had remained unexplored. This is particularly interesting to consider given that in budding yeast, where there are no distinct replicative and non-replicative H3 variants, the single ASF1 ortholog participates in activating transcription of histone genes in S phase and transcriptional repression outside S phase in combination with Hir1, the budding yeast counterpart of HIRA. We thus decided to explore how the key histone chaperones involved in DNA synthesis-coupled chromatin assembly could contribute to the critical regulation of expression of replicative histone genes in human cells during S phase. From total RNA extracted from asynchronous and synchronized human cells, we performed RNA-seq and found that most of the annotated replicative histone genes decreased in expression upon ASF1 depletion by siRNA during S phase compared to the control condition with siRNA againt GFP. However, by 4sU-labeled RNA-seq we detected an increase in newly synthesized replicative histone transcripts. These findings indicate that the decrease in expression of replicative histone genes in ASF1-depleted cells cannot be due to a decrease at the level of transcription. We then inspected closely the sequences at the 3’ end of the replicative histone transcripts in our RNA-seq data and detected a defect of their 3’ processing. Thus, we propose that in mammals ASF1 plays a role in the unique regulation of replicative histone RNA metabolism.
2023-11-29 | E-MTAB-12501 | biostudies-arrayexpress
Project description:Histone acetylation is involved in the regulation of gene expression in plants and eukaryotes. Histone deacetylases (HDACs) are enzymes that catalyze the removal of acetyl groups from histones, which is associated with the repression of gene expression. To study the role of histone acetylation in the regulation of gene expression during seed germination, trichostatin A (TSA), a specific inhibitor of histone deacetylase, was used to treat imbibing Arabidopsis thaliana seeds. GeneChip arrays were used to show that TSA induces up-regulation of 45 genes and down-regulation of 27 genes during seed germination. Eight TSA-up-regulated genes were selected for further analysis - RAB18, RD29B, ATEM1, HSP70 and four late embryogenesis abundant protein genes (LEA). A gene expression time course shows that these eight genes are expressed at high levels in the dry seed and repressed upon seed imbibition at an exponential rate. In the presence of TSA, the onset of repression of the eight genes is not affected but the final level of repressed expression is elevated. Chromatin immunoprecipitation and HDAC assays show that there is a transient histone deacetylation event during seed germination at one day after imbibition, which serves as a key developmental signal that affects the repression of the eight genes. Keywords: histone deacetylase inhibitor, developmental effects
2005-12-10 | GSE3783 | GEO
Project description:The 53BP1-RIF1 pathway antagonizes resection of DNA broken ends and confers PARP inhibitor sensitivity on BRCA1-mutated tumors. However, it is unclear how this pathway suppresses initiation of resection. Here, we identify ASF1 as a partner of RIF1 via an interacting manner similar to its interactions with histone chaperones CAF-1 and HIRA. ASF1 is recruited to distal chromatin flanking DNA breaks by 53BP1-RIF1 and promotes non-homologous end joining (NHEJ) using its histone chaperone activity. Epistasis analysis shows that ASF1 acts in the same NHEJ pathway as RIF1, but via a parallel pathway with the shieldin complex, which suppresses resection after initiation. Moreover, defects in end resection and homologous recombination (HR) in BRCA1-deficient cells are largely suppressed by ASF1 deficiency. Mechanistically, ASF1 compacts adjacent chromatin by heterochromatinization to protect broken DNA ends from BRCA1-mediated resection. Taken together, our findings identified a RIF1-ASF1 histone chaperone complex that promotes changes in high-order chromatin structure to stimulate the NHEJ pathway for DSB repair.
2022-02-04 | PXD031311 | Pride