Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA.
Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA.
Mol Cell. 2014 May 8;54(3):418-30. doi: 10.1016/j.molcel.2014.03.019. Epub 2014 Apr 10.
Rrp6-mediated nuclear RNA surveillance tunes eukaryotic transcriptomes through noncoding RNA degradation and mRNA quality control, including exosomal RNA decay and transcript retention triggered by defective RNA processing. It is unclear whether Rrp6 can positively regulate noncoding RNAs and whether RNA retention occurs in normal cells. Here we report that AtRRP6L1, an Arabidopsis Rrp6-like protein, controls RNA-directed DNA methylation through positive regulation of noncoding RNAs. Discovered in a forward genetic screen, AtRRP6L1 mutations decrease DNA methylation independently of exosomal RNA degradation. Accumulation of Pol V-transcribed scaffold RNAs requires AtRRP6L1 that binds to RNAs in vitro and in vivo. AtRRP6L1 helps retain Pol V-transcribed RNAs in chromatin to enable their scaffold function. In addition, AtRRP6L1 is required for genome-wide Pol IV-dependent siRNA production that may involve retention of Pol IV transcripts. Our results suggest that AtRRP6L1 functions in epigenetic regulation by helping with the retention of noncoding RNAs in normal cells.
Rrp6 介导的核 RNA 监测通过非编码 RNA 降解和 mRNA 质量控制来调节真核转录组，包括由 RNA 加工缺陷触发的外泌体 RNA 衰变和转录物保留。目前尚不清楚 Rrp6 是否可以正向调节非编码 RNA，以及 RNA 保留是否发生在正常细胞中。本文报道称，拟南芥 Rrp6 样蛋白 AtRRP6L1 通过正向调控非编码 RNA 来控制 RNA 指导的 DNA 甲基化。AtRRP6L1 是在正向遗传学筛选中发现的，其突变可独立于外泌体 RNA 降解而降低 DNA 甲基化。AtRRP6L1 促进 Pol V 转录的支架 RNA 的积累，该蛋白可在体外和体内与 RNA 结合。AtRRP6L1 有助于保留 Pol V 转录的 RNA 在染色质中，以发挥其支架功能。此外，AtRRP6L1 对于全基因组依赖于 Pol IV 的 siRNA 产生是必需的，这可能涉及 Pol IV 转录物的保留。我们的结果表明，AtRRP6L1 通过帮助正常细胞中非编码 RNA 的保留来发挥其在表观遗传调控中的作用。
