Regulation of ectopic heterochromatin-mediated epigenetic diversification by the JmjC family protein Epe1

Sorida, M., Hirauchi, T., Ishizaki, H., Kaito, W., Shimada, A., Mori, C., Chikashige, Y., Hiraoka, Y., Suzuki, Y., Ohkawa, Y., Kato, H., Takahata, S., Murakami, Y. (June 2019) Regulation of ectopic heterochromatin-mediated epigenetic diversification by the JmjC family protein Epe1. PLoS Genet, 15 (6). e1008129. ISSN 1553-7390

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URL: https://www.ncbi.nlm.nih.gov/pubmed/31206516
DOI: 10.1371/journal.pgen.1008129

Abstract

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 (epe1Delta) 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 epe1Delta 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 epe1Delta 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.

Item Type: Paper
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > chromatin remodeling
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > epigenetics
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > epigenetics

bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > Chromatin dynamics > heterochromatin
CSHL Authors:
Communities: CSHL labs > Martienssen lab
Depositing User: Matthew Dunn
Date: 17 June 2019
Date Deposited: 12 Aug 2019 15:50
Last Modified: 12 Aug 2019 15:50
PMCID: PMC6576747
Related URLs:
URI: http://repository.cshl.edu/id/eprint/38200

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