DNA polymerase zeta contributes to heterochromatin replication to prevent genome instability
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PROVIDER: PRJNA741504 | ENA |
REPOSITORIES: ENA
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Project description:The DNA polymerase zeta (Polζ) plays a critical role in bypassing DNA damage. REV3L, the catalytic subunit of Polζ is also essential in mouse embryonic development and cell proliferation for reasons that remain incompletely understood. In this study, we reveal that REV3L protein interacts with heterochromatin components including repressive histone marks, and localizes in pericentromeric regions through direct interaction with HP1 dimer. We demonstrate that Polζ/REV3L ensures progression of replication forks through difficult-to-replicate pericentromeric heterochromatin, thereby preventing spontaneous DNA and chromosome break formation. We also find that Rev3l-deficient cells are compromised in the repair of heterochromatin-associated DSBs, eliciting deletions in late replicating regions. Lack of REV3L leads to further consequences that may be ascribed to heterochromatin replication-associated functions of Polζ, with a disruption of the temporal replication program at specific loci. This is correlated with changes in epigenetic landscape and transcriptional control of developmentally regulated genes. These results reveal a new function of Polζ in preventing chromosome instability during replication of heterochromatic regions.
2021-08-20 | GSE178927 | GEO
Project description: Not available
| S-EPMC8561639 | biostudies-literature
Project description: Not available
| S-SCDT-EMBOJ-2020-104543 | biostudies-other
Project description:We found changes in the transcriptome due to disruption Rev3l, the catalytic subunit of DNA polymerase zeta. In particular, we found upregulation of interferon-stimulated genes in Rev3l disrupted MEFs.
2021-02-08 | GSE163313 | GEO
Project description:Chromatin remodelers are recurrently mutated in cancer. Among these, JARID1C, (KDM5C) a histone demethylase, is frequently inactivated in clear cell renal cell carcinoma (ccRCC) patients. How the genetic inactivation of JARID1C leads to cancer remains largely unknown. Here we report that JARID1C binds to broad chromatin domains characterized by the trimethylation of lysine 9 (H3K9me3), an histone mark enriched in heterochromatin. We also found that JARID1C localizes on heterochromatin, is required for heterochromatin replication, and forms a complex with established and novel players of heterochromatin assembly, such as SUV39H1 and HP1 and the CUL4 complex adaptor protein DDB1, respectively. To safeguard the genome, transcription on heterochromatin is tightly suppressed. JARID1C inactivation leads to the unrestrained expression of heterochromatic ncRNAs, that in turn trigger genomic instability. Remarkably, ccRCC patients harbouring JARID1C mutations show aberrant ncRNA expression and increased genomic rearrangements when compared with tumors endowed with other genetic lesions. Together, these data suggest that the inactivation of JARID1C in renal cancer leads to heterochromatin disruption and to aggressive, genomically rearranged ccRCCs, shedding light on a novel mechanism underlying genomic instability in sporadic cancers. We performed ChIP-sequencing for KDM5C, H3K9me3, H3K4me1 and H3K4me3 in Caki-1 untreated cells. Platform HiSeq2500.
2015-11-09 | E-GEOD-73267 | biostudies-arrayexpress
Project description:We describe the epigenetic profiling of the H3K9me2 and HP1a in Drosophila third instar larvae before and after CDK12 depletion by RNA interference (RNAi). Here we show that CDK12 regulates heterochromatin dynamics in Drosophila chromosomes. Depletion of CDK12 induces the increased HP1a and H3K9me2 binding profile on the coding region of euchromatic genes, with the X chromosome being the most affected. These results are consistent with the polytene chromosome immunostaining pattern of HP1a and H3K9me2 after CDK12 knockdown in our initial cytological observations, which show that CDK12 depletion induce heterochromatin spreading on euchromatic arms, especially on the X chromosome. This study describes a novel role of the CDK12 complex in controlling the epigenetic transition between euchromatin and heterochromatin. Examination of the genome-wide H3K9me2 and HP1a binding profile in wildtype larvae (WT) and CDK12-depleted larvae (CDK12-KD). Examination of the genome-wide CDK12 binding profile in wildtype larvae (WT). Twelve independent immunoprecipitations were conducted for each antibody. Two biological replicates were performed.
2015-11-02 | E-GEOD-63011 | biostudies-arrayexpress
Project description:Heterochromatin spreading leads to the silencing of genes within its path, and boundary elements have evolved to constrain such spreading. In fission yeast, heterochromatin at centromeres I and III is flanked by inverted repeats termed IRCs, which are required for proper boundary functions. However, the mechanisms by which IRCs prevent heterochromatin spreading are unknown. Here, we identified Bdf2, homologous to the mammalian BET family of double bromodomain proteins involved in diverse types of cancers, as a factor required for proper boundary function at IRCs. Bdf2 is enriched at IRCs through its interaction with the boundary protein Epe1. The bromodomains of Bdf2 recognize acetylated histone H4 tails and antagonize Sir2-mediated deacetylation of histone H4K16 to prevent heterochromatin spreading. Our results thus illustrate a mechanism of establishing chromosome boundaries at specific sites through the recruitment of a factor that protects euchromatic histone modifications. They also reveal a previously unappreciated function of H4K16 acetylation, which cooperates with H3K9 methylation to regulate heterochromatin spreading. Two samples, H4K16ac & Bdf2-Flag
2013-09-24 | E-GEOD-46430 | biostudies-arrayexpress
Project description:Linker histone H1 prevents R-loop accumulation and genome instability in heterochromatin
| PRJNA387003 | ENA
Project description:Interplay between metabolic state of the cell and its ability to undergo immunological activation has been recently recognized as a treasure chest of novel fundamental regulatory principles. Itaconate, and its membrane permeable derivative dimethyl itaconate (DI) were recently shown to selectively inhibit subset of cytokines during macrophage activation (e.g. Il1b, il6, Il12b but not TNF), yet the precise mechanism of this effect remained unclear. We find that selectivity of DI action stems from the inhibitory effects of electrophilic stress exerted by DI on IkB-zeta protein translation, leading to selective control of the secondary wave of Nfkb-signaling. Mechanistically, DI leads to glutathione depletion and subsequent activation of both Nrf2-dependent and Nrf2-independent stress responses. We find that IkB-zeta regulation is carried out in Nrf2-independent manner, and identify Atf3 as a key mediator of DI effects on IkB-zeta/IL6. This inhibitory effect is conserved across species and cell types, as evident from inhibition of IkB-zeta production in activating human monocytes and IL-17A stimulated keratinocytes of both human and mice. Finally, DI administration in vivo ameliorated IL17/IkB-zeta-driven skin pathology in the mouse model of psoriasis, highlighting therapeutic potential of this regulatory pathway.
2018-04-21 | GSE102190 | GEO
Project description:Yeast Saccharomyces cerevisiae has been widely used as a model system for studying genome instability. Here, a heterozygous diploid S. cerevisiae strain DZP2 was generated to determine the genomic alterations induced by DNA polymerase ε. The expression of POL2 was regulated by the GAL1 promoter. In combination of a custom SNP microarray, the patterns of chromosomal instability induced by low Pol ε could be explored at a whole genome level in DZP2. Using this system, we found hundreds-fold higher rate of genomic alterations, including aneuploidy, loss of heterozygosity (LOH), and chromosomal rearrangement. DNA polymerase ε (Pol ε) is one of the three replicative eukaryotic DNA polymerases. Pol ε deficiency leads to genomic instability and multiple human diseases. Here, we explored global genomic alterations in yeast strains with reduced expression of POL2, the gene that encodes the catalytic subunit of Pol ε. Using whole-genome SNP microarray and sequencing, we found that low levels of Pol ε elevated the rates of mitotic recombination and chromosomal aneuploidy by two orders of magnitude. Strikingly, low levels of Pol ε resulted in a contraction of the number of repeats in the rDNA cluster and reduced the length of telomeres. These short telomeres led to an elevated frequency of break-induced replication, resulting in terminal loss of heterozygosity. In addition, low levels of Pol ε increased the rate of single-base mutations by 13-fold by a Pol ζ-dependent pathway. Finally, the patterns of genomic alterations caused by low levels of Pol ε were different from those observed in strains with low levels of the other replicative DNA polymerases Pol α and Pol δ, providing further insights into the different roles of the B-family DNA polymerases in maintaining genomic stability.
2021-10-07 | GSE185365 | GEO