The Function of piRNAs and the piRNA Complex

小的非编码rna是生物体内基因调控回路的核心组成部分。为了适当的健康和发育，生物体利用含有小内源性rna的蛋白质复合物通过沉默机制控制成千上万的其他基因。模式生物的遗传学暗示了小RNA、Argonaute蛋白和调节染色质结构的过程之间的联系，这表明RNA干扰（RNAi）途径可以影响基因组的大区域。为了在哺乳动物中寻找类似的链接，我们从大鼠睾丸中纯化了piRNA复合物（piRC），该复合物至少由哺乳动物Piwi和Piwi相互作用的rna组成。wi- fi相互作用rna （pirna）是一类比microrna长且来自1- look kb长度的基因间簇的小rna。Piwi是Argonaute家族的一个亚分支，对果蝇和雄性小鼠的生育能力至关重要，并且在基因上与转座因子的沉默有关。尽管具有这些特征，但对piRC的分子功能仍缺乏严格的了解。

Small noncoding RNAs are central components ofthe gene regulatory circuit in organisms. For proper health and development, organisms employ protein complexes containing small endogenous RNAs to control thousands of other genes through silencing mechanism. Genetics in model organisms implicate a link between small RNAs, Argonaute proteins and processes that regulate chromatin structure, suggesting that RNA interference ^RNAi) pathways can impact large domains of the genome. Our search for an analogous link in mammals directed us to purify from rat testes the piRNA Complex (piRC), which consists at least of mammalian Piwi and the Piwi-interacting RNAs. Fiwi-interacting RNAs (piRNAs) are a diverse class of small RNAs that are longer than microRNAs and derive from intergenic clusters of between 1-lOOkb long. Piwi, a subclade of the Argonaute family, is essential for fertility in flies and male mice, and has been genetically implicated in silencing of transposable elements. Despite these features, a rigorous understanding of piRC's molecular function is still lacking. This proposal seeks to dissect the molecular function ofthe piRNAs and piRC through these specific aims: 1) Functional analysis ofthe piRNA Complex; 2) Regulation of piRNA cluster transcription; 3) Understanding the Genesis of piRNAs. We will apply our current biochemical techniques to probe piRC's functional activity, and develop genetic and cell biology methodologies to understand the role of piRNA clusters. Piwi proteins have been shown to be essential for proper germ cell development in animals, including mammals. However, the mechanistic understanding and gene regulatory potential ofthis ribonucleoprotein is still uncharted. This research project aims to develop systems that will drive progress in a subject relevant to child health and human development.