One Loop to Rule Them All: The Ping-Pong Cycle and piRNA-Guided Silencing.
One Loop to Rule Them All: The Ping-Pong Cycle and piRNA-Guided Silencing.
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DOI：
10.1016/j.tibs.2015.12.008
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发表时间：
2016-04
影响因子：
13.8
通讯作者：
Hannon GJ
中科院分区：
文献类型：
--
作者：
Czech B;Hannon GJ
PIWI相互作用RNA（皮尔纳）途径是一种保守的防御机制，其保护动物生殖细胞的遗传信息免受分子寄生虫（如转座子）的有害影响。这种小RNA沉默系统是在近十年前发现的，它包括PIWI进化枝Argonaute蛋白及其相关的RNA结合伴侣piRNA。在这篇综述中，我们重点介绍了最近的工作，这些工作促进了我们对piRNA如何跨代保持基因组完整性的理解。我们讨论了皮尔纳生物发生的机制，概述了共同的主题以及物种之间piRNA介导的沉默的差异，并通过强调piRNA的已知和新兴功能结束。果蝇生殖细胞中皮尔纳前体的转录和稳定需要Rhino-Deadlock-Cutoff复合物。初级皮尔纳生物合成发生在Yb体处，并且取决于内切核酸酶小西葫芦和几种另外的锚定因子。Tudor蛋白的严格控制的协同相互作用在乒乓循环中是必要的，以确保皮尔纳扩增的适当靶向。通过乒乓循环的次级皮尔纳加工和初级皮尔纳生物发生是相互关联的。转座子切割导致产生与Piwi相关并介导转录基因沉默的定相皮尔纳群体。通过Piwi进行的转录基因沉默依赖于Asterix和Panoramix，将皮尔纳途径与一般沉默机制联系起来。
The PIWI-interacting RNA (piRNA) pathway is a conserved defense mechanism that protects the genetic information of animal germ cells from the deleterious effects of molecular parasites, such as transposons. Discovered nearly a decade ago, this small RNA silencing system comprises PIWI-clade Argonaute proteins and their associated RNA-binding partners, the piRNAs. In this review, we highlight recent work that has advanced our understanding of how piRNAs preserve genome integrity across generations. We discuss the mechanism of piRNA biogenesis, give an overview of common themes as well as differences in piRNA-mediated silencing between species, and end by highlighting known and emerging functions of piRNAs. Transcription and stabilization of piRNA precursors in Drosophila germ cells require the Rhino-Deadlock-Cutoff complex. Primary piRNA biogenesis takes place at Yb bodies and depends on the endonuclease Zucchini and several additional mitochondria-anchored factors. A tightly controlled, concerted interplay of Tudor proteins is necessary within the ping-pong cycle to ensure appropriate targeting of piRNA amplification. Secondary piRNA processing through the ping-pong cycle and primary piRNA biogenesis are interconnected. Transposon slicing results in the generation of phased piRNA populations that associate with Piwi and mediate transcriptional gene silencing. Transcriptional gene silencing via Piwi depends on Asterix and Panoramix, linking the piRNA pathway to the general silencing machinery.