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Elife. 2018 Jan 3;7. pii: e31216. doi: 10.7554/eLife.31216.

Telomere repeats induce domains of H3K27 methylation in Neurospora.

Author information

1
Institute of Molecular Biology, University of Oregon, Eugene, United States.
2
Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
#
Contributed equally

Abstract

Development in higher organisms requires selective gene silencing, directed in part by di-/trimethylation of lysine 27 on histone H3 (H3K27me2/3). Knowledge of the cues that control formation of such repressive Polycomb domains is extremely limited. We exploited natural and engineered chromosomal rearrangements in the fungus Neurospora crassa to elucidate the control of H3K27me2/3. Analyses of H3K27me2/3 in strains bearing chromosomal rearrangements revealed both position-dependent and position-independent facultative heterochromatin. We found that proximity to chromosome ends is necessary to maintain, and sufficient to induce, transcriptionally repressive, subtelomeric H3K27me2/3. We ascertained that such telomere-proximal facultative heterochromatin requires native telomere repeats and found that a short array of ectopic telomere repeats, (TTAGGG)17, can induce a large domain (~225 kb) of H3K27me2/3. This provides an example of a cis-acting sequence that directs H3K27 methylation. Our findings provide new insight into the relationship between genome organization and control of heterochromatin formation.

KEYWORDS:

H3K27; N. crassa; chromosome rearrangements; chromosomes; genes; polycomb repressive complex 2; position effect; telomere repeats

PMID:
29297465
PMCID:
PMC5752202
DOI:
10.7554/eLife.31216
[Indexed for MEDLINE]
Free PMC Article

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