Telomere repeats induce domains of H3K27 methylation in Neurospora.
Telomere repeats induce domains of H3K27 methylation in Neurospora.
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DOI：
10.7554/elife.31216
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发表时间：
2018-01-03
期刊：
影响因子：
7.7
通讯作者：
Selker EU
中科院分区：
文献类型：
--
作者：
Jamieson K;McNaught KJ;Ormsby T;Leggett NA;Honda S;Selker EU
高等生物的发育需要选择性的基因沉默，部分是通过组蛋白H3(H3K27me2/3)上赖氨酸27的二三甲基化来指导的。对控制这种抑制性多梳域形成的线索的了解极其有限。我们利用粗糙脉孢菌的自然和工程染色体重排来阐明H3K27me2/3的控制。对携带染色体重排的菌株进行H3K27me2/3的分析发现，兼性异染色质既有位置依赖性的，也有位置非依赖性的。我们发现，接近染色体末端对于维持并充分诱导转录抑制的亚端粒H3K27me2/3是必要的，并且足以诱导。我们确定这种端粒-近端兼性异染色质需要天然的端粒重复序列，并发现短阵列的异位端粒重复序列(TTAGGG)17可以诱导H3K27me2/3的一个大区域(~225kb)。这为指导H3K27甲基化的顺式作用序列提供了一个例子。我们的发现为基因组组织和异染色质形成控制之间的关系提供了新的见解。
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.