A ROLE FOR THE P-BODY COMPONENT GW182 IN MICRORNA FUNCTION

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。在动物中，大多数microRNAs通过RNA干扰(RNAi)机制调节基因表达，而不诱导小干扰RNA(SiRNA)指导的mRNA切割1。因此，microRNAs抑制其靶标的机制仍然难以捉摸。最近，作为RNAi效应关键成分的ArgAerte蛋白及其靶mRNAs被证明定位于被称为P-Body或GW-Bodies2，3的细胞质焦点上。在这里，我们证明了ArgAerte蛋白与关键的P-/GW-Body亚单位GW182物理上相互作用。GW182的沉默会使驻留的P-/GW体蛋白离域，并损害microRNA记者的沉默。此外，阻止ArgAerte蛋白定位在P-/GW小体中的突变阻止了mRNAs的翻译抑制，即使当ArgAerte以不依赖于siRNA的方式与其靶标捆绑在一起时也是如此。因此，我们的结果支持细胞质P-小体和microRNA抑制靶mRNA表达的能力之间的功能联系。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In animals, the majority of microRNAs regulate gene expression through the RNA interference (RNAi) machinery without inducing small-interfering RNA (siRNA)-directed mRNA cleavage1. Thus, the mechanisms by which microRNAs repress their targets have remained elusive. Recently, Argonaute proteins, which are key RNAi effector components, and their target mRNAs were shown to localize to cytoplasmic foci known as P-bodies or GW-bodies2, 3. Here, we show that the Argonaute proteins physically interact with a key P-/GW-body subunit, GW182. Silencing of GW182 delocalizes resident P-/GW-body proteins and impairs the silencing of microRNA reporters. Moreover, mutations that prevent Argonaute proteins from localizing in P-/GW-bodies prevent translational repression of mRNAs even when Argonaute is tethered to its target in a siRNA-independent fashion. Thus, our results support a functional link between cytoplasmic P-bodies and the ability of a microRNA to repress expression of a target mRNA.