Schizosaccharomyces pombe
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REPOSITORIES: ENA
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Project description:H3K9 methylation (H3K9me) is a conserved marker of heterochromatin, a transcriptionally silent chromatin structure. Knowledge of the mechanisms for regulating heterochromatin distribution is limited. The fission yeast JmjC domain-containing protein Epe1 localizes to heterochromatin mainly through its interaction with Swi6, a homologue of heterochromatin protein 1 (HP1), and directs JmjC-mediated H3K9me demethylation in vivo. Here, we found that loss of epe1 (epe1∆) induced a red-white variegated phenotype in a red-pigment accumulation background that generated uniform red colonies. Analysis of isolated red and white colonies revealed that silencing of genes involved in pigment accumulation by stochastic ectopic heterochromatin formation led to white colony formation. In addition, genome-wide analysis of red- and white-isolated clones revealed that epe1∆ resulted in a heterogeneous heterochromatin distribution among clones. We found that Epe1 had an N-terminal domain distinct from its JmjC domain, which activated transcription in both fission and budding yeasts. The N-terminal transcriptional activation (NTA) domain was involved in suppression of ectopic heterochromatin-mediated red-white variegation. We introduced a single copy of Epe1 into epe1∆ clones harboring ectopic heterochromatin, and found that Epe1 could reduce H3K9me from ectopic heterochromatin but some of the heterochromatin persisted. This persistence was due to a latent H3K9me source embedded in ectopic heterochromatin. Epe1H297A, a canonical JmjC mutant, suppressed red-white variegation, but entirely failed to remove already-established ectopic heterochromatin, suggesting that Epe1 prevented stochastic de novo deposition of ectopic H3K9me in an NTA-dependent but JmjC-independent manner, while its JmjC domain mediated removal of H3K9me from established ectopic heterochromatin. Our results suggest that Epe1 not only limits the distribution of heterochromatin but also controls the balance between suppression and retention of heterochromatin-mediated epigenetic diversification.
2019-04-24 | GSE108448 | GEO
Project description:Loss of Epe1 induces epigenetic diversification among epiclones
| PRJDB6424 | ENA
Project description:Epe1 recruits the BET family bromodomain protein Bdf2 to establish heterochromatin boundaries
| PRJNA200317 | ENA
Project description:Nuclear aconitase regulates heterochromatin formation by interacting with Chp1
| PRJNA395555 | ENA
Project description:The 19S proteasome regulates subtelomere silencing and facultative heterochromatin formation
| PRJNA401892 | ENA
Project description:RNA elimination machinery targeting meiotic mRNAs promotes facultative heterochromatin formation
| PRJNA149103 | ENA
Project description:Argonaute Surveillance and Dicer-Independent priRNAs TriggerRNAi and Heterochromatin Formation
| PRJNA122193 | ENA
Project description:The epigenetic landscape of a cell frequently changes in response to fluctuations in nutrient levels, but the mechanistic link is not well understood. In fission yeast, the JmjC domain protein Epe1 is critical for maintaining the heterochromatin landscape. Loss of Epe1 results in heterochromatin expansion and overexpression of Epe1 leads to defective heterochromatin. Through a genetic screen, we found that mutations in genes of the cAMP signaling pathway suppress the heterochromatin defects associated with Epe1 overexpression. We further demonstrated that the activation of Pka1, the downstream effector of cAMP signaling, is required for the efficient translation of epe1+ mRNA to maintain Epe1 overexpression. Moreover, inactivating the cAMP-signaling pathway, either through genetic mutations or glucose deprivation, leads to the reduction of endogenous Epe1 and corresponding heterochromatin changes. These results reveal the mechanism by which the cAMP signaling pathway regulates heterochromatin landscape in fission yeast.
2022-01-10 | GSE181263 | GEO
Project description:Distinct Functions of Argonaute Slicer in siRNA Maturation and Heterochromatin Formation [ChIP-Seq]
| PRJNA322452 | ENA
Project description:Distinct Functions of Argonaute Slicer in siRNA Maturation and Heterochromatin Formation [ncRNA-seq 2]
| PRJNA322455 | ENA