Tudor Domain Proteins in Germline Genome Defense

项目总结 转座元件(TES)是一种可以复制和重新整合的“基因组寄生虫” 进入宿主细胞基因组。生殖细胞中不受控制的TE活动会导致DNA损伤， 配子发育中断和不孕不育。在哺乳动物的雄性生殖细胞中，PIWI- PiRNA途径以小RNA为导向沉默可移动的TES以保护基因组 正直和维持生育能力。PIRNA的正确产生对于TE沉默是至关重要的 和精子发生。然而，控制piRNA生物发生的机制并不是 很好理解。特别是，许多RNA结合蛋白在piRNA过程中的作用 生物发生仍然难以捉摸。通过研究都铎结构域蛋白的一个子组，也 我们发现TDRD5是一种新的RNA结合蛋白 对小鼠的piRNA生物发生至关重要。令人惊讶的是，我们发现了一种新的RNA 莲花结构域的结合特性，在细菌、植物和动物中保守。 这种结合特性与已报道的某些动物的蛋白质结合特性不同 莲花域。我们假设动物的莲花结构域既有RNA又有 蛋白质结合活性与莲花都铎结构域蛋白的结合 在哺乳动物piRNA的生物发生中起着关键作用。为了检验这一假设，我们将使用 生化方法和小鼠模型：1)阐明RNA和蛋白质的结合 莲花结构域超家族的活性；2)确定特定的 Lotus域与RNA的相互作用；以及3)定义Lotus域的功能参与 小鼠piRNA生物发生和Vasa调节中的结构域蛋白。这些研究将 对piRNA生物发生的机制提供了有价值的新见解 生殖系基因组完整性，以维持男性生育能力，并在更广泛的领域扩大我们的知识 RNA生物学和发育生物学。

PROJECT SUMMARY Transposable elements (TEs) are “genomic parasites” that can replicate and re-integrate into the host cell genome. Uncontrolled TE activity in germ cells leads to DNA damage, disruption of gametogenesis, and infertility. In mammalian male germ cells, the PIWI- piRNA pathway uses small RNAs as a guide to silence mobile TEs to protect genome integrity and sustain fertility. The proper production of piRNAs is critical for TE silencing and spermatogenesis. However, the mechanisms governing piRNA biogenesis are not well understood. In particular, the roles of many RNA binding proteins during piRNA biogenesis remain elusive. By studying a subgroup of Tudor domain proteins that also harbor LOTUS domains, we discovered that TDRD5 is a novel RNA binding protein critical for piRNA biogenesis in mice. Strikingly, we have discovered a novel RNA binding property of LOTUS domains that is conserved in bacteria, plants and animals. This binding property is different from reported protein binding feature of some animal LOTUS domains. We hypothesize that animal LOTUS domains have both RNA and protein binding activities and that the LOTUS group of Tudor domain proteins together play critical roles in mammalian piRNA biogenesis. To test this hypothesis, we will use biochemical approaches and mouse models to: 1) Clarify the RNA and protein binding activities of the LOTUS domain superfamily; 2) Determine the mechanism of a specific LOTUS domain-RNA interaction; and 3) Define the functional involvement of LOTUS domain proteins in piRNA biogenesis and Vasa regulation in mice. These studies will provide valuable new insights into the mechanisms of piRNA biogenesis that safeguard germline genome integrity to sustain male fertility and expand our knowledge in broader RNA biology and developmental biology.