The Rhino-Deadlock-Cutoff Complex Licenses Noncanonical Transcription of Dual-Strand piRNA Clusters in Drosophila
The Rhino-Deadlock-Cutoff Complex Licenses Noncanonical Transcription of Dual-Strand piRNA Clusters in Drosophila
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DOI：
10.1016/j.cell.2014.04.031
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发表时间：
2014-06-05
期刊：
影响因子：
64.5
通讯作者：
Brennecke, Julius
中科院分区：
文献类型：
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作者：
Mohn, Fabio;Sienski, Grzegorz;Brennecke, Julius
在动物性腺中，PIWI分支的ArgAerte蛋白是转座子沉默的中心。它们的靶标特异性是由23-30个核苷酸的PIWI相互作用RNA(PiRNAs)定义的，这些相互作用的RNAs大多起源于离散的基因组座位，称为piRNA簇。在这里，我们展示了由犀牛、死锁和截断(RDC)组成的复合体在果蝇卵巢中定义了全基因组范围的双链piRNA簇。RDC部分通过犀牛的染色域锚定在H3K9me3标记的染色质上。Piwi的耗尽会导致PiRNA簇子集的RDC和小RNA的丢失，表明Piwi和piRNA源位点之间存在反馈环。有趣的是，RNA聚合酶II的占有率、新生转录和稳定状态RNA水平的谱显示，RDC许可双链piRNA簇的非规范转录。这一过程可能涉及对新生RNA的50端保护和转录终止的抑制。我们的数据为piRNA簇的调控和进化提供了关键的见解。
Argonaute proteins of the PIWI clade are central to transposon silencing in animal gonads. Their target specificity is defined by 23-30 nt PIWI interacting RNAs (piRNAs), which mostly originate from discrete genomic loci termed piRNA clusters. Here, we show that a complex composed of Rhino, Deadlock, and Cutoff (RDC) defines dual-strand piRNA clusters genome-wide in Drosophila ovaries. The RDC is anchored to H3K9me3-marked chromatin in part via Rhino's chromodomain. Depletion of Piwi results in loss of the RDC and small RNAs at a subset of piRNA clusters, demonstrating a feedback loop between Piwi and piRNA source loci. Intriguingly, profiles of RNA polymerase II occupancy, nascent transcription, and steady-state RNA levels reveal that the RDC licenses noncanonical transcription of dual-strand piRNA clusters. Likely, this process involves 50 end protection of nascent RNAs and suppression of transcription termination. Our data provide key insight into the regulation and evolution of piRNA clusters.