Böhmdorfer Gudrun, Sethuraman Shriya, Rowley M Jordan, Krzyszton Michal, Rothi M Hafiz, Bouzit Lilia, Wierzbicki Andrzej T
Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, United States.
Bioinformatics Graduate Program, University of Michigan, Ann Arbor, United States.
Elife. 2016 Oct 25;5:e19092. doi: 10.7554/eLife.19092.
RNA-mediated transcriptional gene silencing is a conserved process where small RNAs target transposons and other sequences for repression by establishing chromatin modifications. A central element of this process are long non-coding RNAs (lncRNA), which in are produced by a specialized RNA polymerase known as Pol V. Here we show that non-coding transcription by Pol V is controlled by preexisting chromatin modifications located within the transcribed regions. Most Pol V transcripts are associated with AGO4 but are not sliced by AGO4. Pol V-dependent DNA methylation is established on both strands of DNA and is tightly restricted to Pol V-transcribed regions. This indicates that chromatin modifications are established in close proximity to Pol V. Finally, Pol V transcription is preferentially enriched on edges of silenced transposable elements, where Pol V transcribes into TEs. We propose that Pol V may play an important role in the determination of heterochromatin boundaries.
RNA介导的转录基因沉默是一个保守的过程，其中小RNA通过建立染色质修饰来靶向转座子和其他序列以进行抑制。这个过程的一个核心要素是长链非编码RNA（lncRNA），它由一种名为Pol V的特殊RNA聚合酶产生。在这里，我们表明Pol V的非编码转录受转录区域内预先存在的染色质修饰控制。大多数Pol V转录本与AGO4相关，但不被AGO4切割。Pol V依赖的DNA甲基化在DNA的两条链上建立，并严格局限于Pol V转录区域。这表明染色质修饰在靠近Pol V的位置建立。最后，Pol V转录优先富集在沉默转座元件的边缘，Pol V在那里转录进入转座子。我们提出Pol V可能在异染色质边界的确定中起重要作用。
