Piwi‐interacting RNAs (piRNAs) play key roles in germline development and genome defence in metazoans. In C. elegans, piRNAs are transcribed from > 15,000 discrete genomic loci by RNA polymerase II (Pol II), resulting in 28 nt short‐capped piRNA precursors. Here, we investigate transcription termination at piRNA loci. We show that the Integrator complex, which terminates snRNA transcription, is recruited to piRNA loci. Moreover, we demonstrate that the catalytic activity of Integrator cleaves nascent capped piRNA precursors associated with promoter‐proximal Pol II, resulting in termination of transcription. Loss of Integrator activity, however, does not result in transcriptional readthrough at the majority of piRNA loci. Taken together, our results draw new parallels between snRNA and piRNA biogenesis in nematodes and provide evidence of a role for the Integrator complex as a terminator of promoter‐proximal RNA polymerase II during piRNA biogenesis.

中文翻译：

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整合子被招募到启动子近端暂停的 RNA Pol II 以生成秀丽隐杆线虫 piRNA 前体

Piwi 相互作用 RNA (piRNA) 在后生动物种系发育和基因组防御中发挥着关键作用。在线虫中，piRNA 由 RNA 聚合酶 II (Pol II) 从超过 15,000 个离散基因组位点转录，产生 28 nt 短帽 piRNA 前体。在这里，我们研究了 piRNA 位点的转录终止。我们发现终止 snRNA 转录的整合复合体被招募到 piRNA 位点。此外，我们证明 Integrator 的催化活性会裂解与启动子近端 Pol II 相关的新生带帽 piRNA 前体，从而导致转录终止。然而，整合子活性的丧失不会导致大多数 piRNA 位点的转录通读。综上所述，我们的结果在线虫中的 snRNA 和 piRNA 生物发生之间得出了新的相似之处，并提供了整合复合物在 piRNA 生物发生过程中作为启动子近端 RNA 聚合酶 II 终止子的作用的证据。