Arabidopsis Serrate Coordinates Histone Methyltransferases ATXR5/6 and RNA Processing Factor RDR6 to Regulate Transposon Expression
Arabidopsis Serrate Coordinates Histone Methyltransferases ATXR5/6 and RNA Processing Factor RDR6 to Regulate Transposon Expression
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DOI：
10.1016/j.devcel.2018.05.023
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发表时间：
2018-06-18
影响因子：
11.8
通讯作者：
Zhang, Xiuren
中科院分区：
文献类型：
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作者：
Ma, Zeyang;Castillo-Gonzalez, Claudia;Zhang, Xiuren
Serrate（SE）是RNA代谢的关键成分。很少有人知道它是否以及如何调节表观遗传沉默。在这里，我们报告组蛋白甲基转移酶ATXR 5和ATXR 6（ATXR 5/6）作为新的合作伙伴的SE。ATXR 5/6存款组蛋白3赖氨酸27单甲基化（H3 K27 me 1）以促进异染色质形成、抑制转座因子（TE）和控制拟南芥基因组稳定性。SE与ATXR 5/6调节的TE位点结合，并促进H3 K27 me 1在这些区域的积累。此外，SE在体外直接增强ATXR 5酶活性。出乎意料的是，se突变抑制了atxr 5 atxr 6突变体中的TE再激活和DNA再复制表型。TE表达的抑制是由于在se atxr 5 atxr 6突变体中触发RNA依赖性RNA聚合酶6（RDR 6）依赖性RNA沉默所致。我们建议SE促进ATXR 5/6介导的H3 K27 me 1标记的沉积，同时抑制RDR 6介导的RNA沉默以保护TE转录物。因此，SE协调表观遗传沉默和RNA加工机制以微调TE表达。
Serrate (SE) is a key component in RNA metabolism. Little is known about whether and how it can regulate epigenetic silencing. Here, we report histone methyl-transferases ATXR5 and ATXR6 (ATXR5/6) as novel partners of SE. ATXR5/6 deposit histone 3 lysine 27 monomethylation (H3K27me1) to promote heterochromatin formation, repress transposable elements (TEs), and control genome stability in Arabidopsis. SE binds to ATXR5/6-regulated TE loci and promotes H3K27me1 accumulation in these regions. Furthermore, SE directly enhances ATXR5 enzymatic activity in vitro. Unexpectedly, se mutation suppresses the TE reactivation and DNA re-replication phenotypes in the atxr5 atxr6 mutant. The suppression of TE expression results from triggering RNA-dependent RNA polymerase 6 (RDR6)-dependent RNA silencing in the se atxr5 atxr6 mutant. We propose that SE facilitates ATXR5/6-mediated deposition of the H3K27me1 mark while inhibiting RDR6-mediated RNA silencing to protect TE transcripts. Hence, SE coordinates epigenetic silencing and RNA processing machineries to fine-tune the TE expression.