The histone chaperone FACT facilitates heterochromatin spreading through regulation of histone turnover and H3K9 methylation states
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ABSTRACT:
PROVIDER: PRJNA730872 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR14578814.fastq.gz | Fastqsanger.gz | |||
| SRR14578815.fastq.gz | Fastqsanger.gz | |||
| SRR14578816.fastq.gz | Fastqsanger.gz | |||
| SRR14578817.fastq.gz | Fastqsanger.gz | |||
| SRR14578818.fastq.gz | Fastqsanger.gz |
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Project description:Heterochromatin formation requires several steps involving: nucleation followed by spreading of large, silent domains and its faithful re-establishment and maintenance after each replication cycle. The essential histone chaperone FACT has been implicated in heterochromatin silencing, however, little is known about the specificity of FACT in this process. Here, by applying single cell assays, ChIP and genetics, we show that FACT mutants have defects in the spreading of heterochromatin at subtelomeres and mating type locus in fission yeast. Further, we demonstrate that the transition of H3K9me2 to me3 is impaired in the FACT mutant and we link the spreading function of FACT to its role in histone turnover suppression. We also identify Epe1 as a specific factor that counteracts heterochromatin spreading defects in the FACT mutants. Together, our studies identify FACT as a first histone chaperone that promotes heterochromatin spreading and add to the current models on histone turnover in propagation of epigenetic marks.
2021-10-12 | GSE174641 | GEO
Project description:Heterochromatin formation requires three distinct steps: nucleation, self-propagation (spreading) along the chromosome, and faithful maintenance after each replication cycle. Impeding any of those steps induces heterochromatin defects and improper gene expression. The essential histone chaperone FACT (facilitates chromatin transcription) has been implicated in heterochromatin silencing, but the mechanisms by which FACT engages in this process remain opaque. Here, we pinpoint its function to the heterochromatin spreading process in fission yeast. FACT impairment reduces nucleation-distal H3K9me3 and HP1/Swi6 accumulation at subtelomeres and derepresses genes in the vicinity of heterochromatin boundaries. FACT promotes spreading by repressing heterochromatic histone turnover, which is crucial for the H3K9me2 to me3 transition that enables spreading. FACT mutant spreading defects are suppressed by removal of the H3K9 methylation antagonist Epe1. Together, our study identifies FACT as a histone chaperone that promotes heterochromatin spreading and lends support to the model that regulated histone turnover controls the propagation of repressive methylation marks.
| S-EPMC8608617 | biostudies-literature
Project description:Heterochromatin formation in Schizosaccharomyces pombe requires the spreading of histone 3 (H3) Lysine 9 (K9) methylation (me) from nucleation centers by the H3K9 methylase, Suv39/Clr4, and the reader protein, HP1/Swi6. To accomplish this, Suv39/Clr4 and HP1/Swi6 have to associate with nucleosomes both nonspecifically, binding DNA and octamer surfaces and specifically, via recognition of methylated H3K9 by their respective chromodomains. However, how both proteins avoid competition for the same nucleosomes in this process is unclear. Here, we show that phosphorylation tunes the nucleosome affinity of HP1/Swi6 such that it preferentially partitions onto Suv39/Clr4’s trimethyl product rather than its unmethylated substrates. Preferential partitioning enables efficient conversion from di-to trimethylation on nucleosomes in vitro and H3K9me3 spreading in vivo. Together, our data suggests that phosphorylation of HP1/Swi6 creates a regime that relieves competition with the “read-write” mechanism of Suv39/Clr4 for productive heterochromatin spreading.
2024-12-02 | GSE271394 | GEO
Project description:The CENP-T/-W histone fold complex, as an integral part of the inner kinetochore, is essential for building a proper kinetochore at the centromere in order to direct chromosome segregation during mitosis. Notably, CENP-T/-W is not inherited at centromeres and new deposition is absolutely required at each cell cycle for kinetochore function. However, the mechanisms underlying this new deposition of CENP-T/-W at centromeres are unclear. Here, we find that CENP-T deposition at centromeres is uncoupled from DNA synthesis. We identify Spt16 and SSRP1, subunits of the H2A-H2B histone chaperone FACT, as CENP-W binding partners through a proteomic screen. We find that the C-terminal region of Spt16 binds specifically to the histone fold region of CENP-T/-W. Furthermore, depletion of Spt16 impairs CENP-T and CENP-W deposition at endogenous centromeres and site directed targeting of Spt16 alone is sufficient to ensure local de novo CENP-T accumulation. We propose a model in which the FACT chaperone stabilizes the soluble CENP-T/-W complex in the cell and promotes dynamics of exchange, enabling CENP-T/-W deposition at centromeres.
2016-06-14 | PXD004099 | Pride
Project description:Parental histone recycling is essential for the restoration of chromatin-based epigenetic information during chromatin replication; however, the specific mechanisms underlying the local recycling of parental histones remain poorly understood. Here, we reveal an unexpected role of the Spt16-N domain in histone chaperone FACT during parental histone recycling and transfer in budding yeast. We found that depletion of Spt16 or mutations in the Spt16 middle domain leads to defects in both parental histone recycling and new histone deposition, affecting both the leading and lagging strands of DNA replication forks, highlighting the essential role of the FACT complex in both parental histone recycling and new histone deposition. Surprisingly, Spt16-N deletion results in an apparent defect in parental histone recycling, with a more pronounced defect on the lagging strand than the corresponding leading strand. Mechanistically, the Spt16-N domain acts as a protective barrier, shielding FACT-bound histone H3-H4 and facilitating its interaction with Mcm2, which ensures efficient local parental histone recycling. Collectively, the Spt16-N domain provides a protein–protein interaction module allowing FACT to act as a shuttle chaperone, cooperate with multiple replisome components, which act as co-chaperones, to form a complex involving the shuttle chaperone, histones, and co-chaperones, during parental histone recycling and transfer.
2024-01-26 | PXD043392 | Pride
Project description:The differentiation of embryonic stem cells (ESCs) begins with the transition from the naive to the primed state. The formative state was recently established as a critical intermediate between the two states. Here, we demonstrate the role of the histone chaperone FACT in regulating the naive-to-formative transition. We found that the Q265K mutation in the FACT subunit SSRP1 increased the binding of FACT to histone H3-H4, impaired nucleosome disassembly in vitro, and reduced the turnover of FACT on chromatin in vivo. Strikingly, mouse ESCs harboring this mutation showed elevated naive-to-formative transition. Mechanistically, the SSRP1-Q265K mutation enriched FACT at the enhancers of formative-specific genes to increase targeted gene expression. Together, these findings suggest that the turnover of FACT on chromatin is crucial for regulating the enhancers of formative-specific genes, thereby mediating the naive-to-formative transition. This study highlights the significance of FACT in fine-tuning cell fate transition during early development.
| S-EPMC10783625 | biostudies-literature
Project description:Cas9 is a prokaryotic RNA-guided DNA endonuclease that binds substrates tightly in vitro but turns over rapidly when used to manipulate genomes in eukaryotic cells. Little is known about the factors responsible for dislodging Cas9 or how they influence genome engineering. Unbiased detection through proximity labeling of transient protein interactions in cell-free Xenopus laevis egg extract identified the dimeric histone chaperone facilitates chromatin transcription (FACT) as an interactor of substrate-bound Cas9. FACT is both necessary and sufficient to displace dCas9, and FACT immunodepletion converts Cas9's activity from multi-turnover to single turnover. In human cells, FACT depletion extends dCas9 residence times, delays genome editing, and alters the balance between indel formation and homology-directed repair. FACT knockdown also increases epigenetic marking by dCas9-based transcriptional effectors with a concomitant enhancement of transcriptional modulation. FACT thus shapes the intrinsic cellular response to Cas9-based genome manipulation most likely by determining Cas9 residence times.
| S-EPMC7398558 | biostudies-literature
Project description:Nucleosome assembly in vivo requires assembly factors, such as histone chaperones, to bind to histones and mediate their deposition onto DNA. In yeast, the essential histone chaperone FACT (FAcilitates Chromatin Transcription) functions in nucleosome assembly and H2A-H2B deposition during transcription elongation and DNA replication. Recent studies have identified candidate histone residues that mediate FACT binding to histones, but it is not known which histone residues are important for FACT to deposit histones onto DNA during nucleosome assembly. In this study, we report that the histone H2B repression (HBR) domain within the H2B N-terminal tail is important for histone deposition by FACT. Deletion of the HBR domain causes significant defects in histone occupancy in the yeast genome, particularly at HBR-repressed genes, and a pronounced increase in H2A-H2B dimers that remain bound to FACT in vivo. Moreover, the HBR domain is required for purified FACT to efficiently assemble recombinant nucleosomes in vitro. We propose that the interaction between the highly basic HBR domain and DNA plays an important role in stabilizing the nascent nucleosome during the process of histone H2A-H2B deposition by FACT. 6 samples, 2 inputs and 4 ChIP samples for histone H2B (2 for wild-type and 2 for an H2B â30-37 mutant)
2016-08-10 | E-GEOD-80831 | biostudies-arrayexpress
Project description:The FACT complex and Spt6 are conserved histone chaperones that are recruited to the open reading frames of transcribed genes. In this study, we provide evidence that FACT interaction with acetylated H3 tail is important for its localization to the coding sequences. Pol II CTD kinase Kin28 additionally stimulates FACT recruitment to a subset of genes. Pol II occupancies in the 5’ ends of transcribed genes are greatly reduced on depleting FACT, whereas reduced occupancies at the 3’ ends were observed upon Spt6 depletion indicating that these factors modulate Pol II progression through distinct regions of transcribed coding sequences. While FACT is largely responsible for reassembling histones, we uncover a role for Spt6 in promoting histone eviction in addition to widely-accepted role for Spt6 in histone reassembly. Consistent with their localization in the coding regions, simultaneously impairing FACT and Spt6 function severely dampens histone eviction and impairs transcription genome-wide. ChIP-chip experiments to measure Spt16 occupancies in WT and kin28as mutant, as well Rpb3 and histone H3 occupancies in undepleted or depleted cells for Spt16 and Spt6, and also in the strain lacking Spt6 tandem SH2 domain
2018-05-21 | GSE69642 | GEO
Project description:The heterodimeric histone chaperone FACT consisting of SSRP1 and SPT16 contributes to dynamic nucleosome rearrangements during various DNA-dependent processes including transcription. In search of post-translational modifications that may regulate the activity of FACT, SSRP1 and SPT16 were isolated from Arabidopsis cells and analysed by mass spectrometry. Four acetylated lysine residues could be mapped within the basic C-terminal region of SSRP1, while three phosphorylated serine/threonine residues were identified in the acidic C-terminal region of SPT16. Mutational analysis of the SSRP1 acetylation sites revealed only mild effects. However, phosphorylation of SPT16 that is catalysed by protein kinase CK2, modulates histone interactions. A non-phosphorylatable version of SPT16 displayed reduced histone binding and (unlike the phosphorylatable wild-type and phosphomimic versions) proved inactive in complementing the growth and developmental phenotypes of spt16 mutant plants. In plants expressing the non-phosphorylatable SPT16 version we detected at a subset of genes enrichment of histone H3 directly upstream of RNA polymerase II transcriptional start sites (TSSs) in a region that usually is nucleosome-depleted. This is associated with altered transcript levels, suggesting that some genes require phosphorylation of the SPT16 acidic region for establishing the correct nucleosome occupancy at the TSS as a prerequisite for proper transcription.
2022-06-09 | PXD028534 | Pride