Université Clermont Auvergne, CNRS, Inserm, GReD, Clermont-Ferrand F-63000, France.
Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan.
Nat Commun. 2017 May 3;8:15122. doi: 10.1038/ncomms15122.
Transposable elements (TEs) are prevalent in most eukaryotes, and host genomes have devised silencing strategies to rein in TE activity. One of these, transcriptional silencing, is generally associated with DNA methylation and short interfering RNAs. Here we show that the Arabidopsis genes MAIL1 and MAIN define an alternative silencing pathway independent of DNA methylation and short interfering RNAs. Mutants for MAIL1 or MAIN exhibit release of silencing and appear to show impaired condensation of pericentromeric heterochromatin. Phylogenetic analysis suggests not only that MAIL1 and MAIN encode a retrotransposon-related plant mobile domain, but also that host plant mobile domains were captured by DNA transposons during plant evolution. Our results reveal a role for Arabidopsis proteins with a transposon-related domain in gene silencing.
转座元件 (TEs) 在大多数真核生物中普遍存在，而宿主基因组则设计了沉默策略来控制 TE 的活性。其中一种策略是转录沉默，通常与 DNA 甲基化和小干扰 RNA 相关。在这里，我们表明拟南芥基因 MAIL1 和 MAIN 定义了一种独立于 DNA 甲基化和小干扰 RNA 的替代沉默途径。MAIL1 或 MAIN 的突变体表现出沉默的释放，并且似乎显示出着丝粒周围异染色质的凝聚受损。系统发育分析不仅表明 MAIL1 和 MAIN 编码与逆转座子相关的植物移动结构域，而且还表明宿主植物移动结构域在植物进化过程中被 DNA 转座子捕获。我们的结果揭示了具有转座子相关结构域的拟南芥蛋白在基因沉默中的作用。
