Role of RNA degradation in germline stem cell to oocyte transition

RNA 降解在生殖干细胞向卵母细胞转变中的作用

• 批准号: 10541733
• 负责人: Prashanth Rangan
• 金额: $ 23.66万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10541733
• 关键词: Role; RNA; degradation; germline; stem

Abstract The germ line generates gametes that link generations by passing genetic information from parent to offspring. During oogenesis, the egg receives critical mRNAs from the mother, called maternal mRNAs, that help launch the next generation; any mistakes in this process could be detrimental to the offspring. However, it is not known if specific mRNAs are selected for deposition, or what, if any, guardians ensure that the right mRNAs are deposited. We have identified Drosophila twister (tst), the homologue of human SKI2VL, as one of the guardians of maternal inheritance. tst encodes an ATP-dependent RNA helicase that is part of the conserved Super Killer (Ski) complex, which funnels mRNA targets from mRNA surveillance pathways to the degradation machinery. We find that tst mutants are viable but females are sterile. Our data suggests that Tst promotes the degradation of mRNAs that are expressed and required in the undifferentiated cells such as germline stem cells (GSCs). We find that this Tst-mediated degradation happens during differentiation before oocytes are specified. Failure to degrade the GSC mRNAs in the differentiated stages results in loss of accumulation maternal mRNAs in the oocyte resulting in oocyte death. We find that Tst-regulated mRNAs contain polypyrimidine tracts (PTs) in the coding sequence (CDS) that can be bound by protein a PT binding protein, Half pint (Hfp), which we find also coregulates a subset of Tst-regulated mRNAs. We hypothesized that Hfp binding in the CDS can block translation by setting up barrier to ribosome movement on the coding sequence (CDS). In support of this hypothesis, we find that a key protein that monitors ribosome stalling on the CDS and can activate the No-Go decay (NGD) surveillance pathway, Pelota, also co-regulates both tst and hfp targets. Our central hypothesis is that the Ski complex detects a subset mRNAs are expressed and function in the GSCs and excludes these mRNAs from becoming part of the maternal inheritance by monitoring for stalled ribosomes. The objective of our proposal is to uncover how Tst and the NGD pathway regulates maternal mRNA inheritance via ribosome stalling. We will address this hypothesis with two specific aims: 1) Define the role of Twister, a component of RNA degradation promoting Super Killer complex, in regulating oogenesis. 2) Ascertain the role of No-Go decay pathway in controlling the selective elimination of mRNAs during oogenesis. The outcomes of our proposed studies are expected to improve scientific knowledge by revealing the extent, mechanism, and functional consequences of Tst and NGD mediated surveillance of the oocyte transcriptome. As loss of the tst human homolog, SKIV2L, results in trichohepatoenteric syndrome (THES) that has no known treatment. These findings will have a positive impact by providing insight into the etiology of diseases such as THES. Further, these studies may reveal potential therapeutic targets for many diseases arising from dysregulated RNA catabolism, including some spinal motor neuropathies.

摘要 生殖细胞系产生配子，通过将遗传信息从父母传递给后代来连接几代人。 在卵子发生过程中，卵子从母亲那里接收关键的mRNAs，称为母体mRNAs， 下一代;这个过程中的任何错误都可能对后代有害。但不 已知是否选择特定的mRNA进行沉积，或者如果有的话，什么监护人确保正确的mRNA 都存了我们已经鉴定出果蝇扭转酶（Drosophila twister，tst），人SKI 2 VL的同源物，作为其中一种。 母性遗传的守护者tst编码一种ATP依赖性RNA解旋酶， 超级杀手（滑雪）复合物，它漏斗mRNA靶从mRNA监视途径的降解 机械.我们发现tst突变体是可行的，但女性不育。我们的数据表明，Tst促进了 在未分化细胞如生殖干细胞中表达和需要的mRNA的降解 细胞（GSC）。我们发现这种Tst介导的降解发生在卵母细胞分化之前， 指定的.在分化阶段未能降解GSC mRNA导致积累损失 卵母细胞中的母体mRNA导致卵母细胞死亡。我们发现Tst调节的mRNA含有 多聚嘧啶段（PT）的编码序列（CDS）中可被PT结合蛋白结合的蛋白， 半品脱（HFP），我们发现也共调节TST调节的mRNA的一个子集。我们假设Hfp CDS中的结合可以通过在编码序列上设置核糖体运动的屏障来阻断翻译 （CDS）。为了支持这一假设，我们发现一种关键的蛋白质，监测核糖体停滞在CDS上， 可以激活No-Go衰变（NGD）监视途径，Pelota还共调节tst和hfp靶。 我们的中心假设是，Ski复合物检测到一个亚组的mRNA表达和功能， GSC和排除这些mRNA成为母系遗传的一部分，通过监测停滞的 核糖体我们的建议的目的是揭示Tst和NGD通路如何调节母体的 通过核糖体停滞的mRNA遗传。我们将通过两个具体目标来解决这个假设：1）定义 Twister是RNA降解促进超级杀手复合物的一种成分，在调节卵子发生中的作用。（二） 确定卵子发生过程中No-Go衰变途径在控制mRNA选择性消除中的作用。 我们提出的研究结果有望通过揭示疾病的程度， 机制和功能后果的Tst和NGD介导的监督卵母细胞转录组。 由于tst人类同源物SKIV 2L的缺失导致了不明原因的肝肠综合征（THES）， 治疗这些发现将产生积极的影响，通过提供深入了解疾病的病因，如 帖前此外，这些研究可能揭示许多疾病的潜在治疗靶点， 失调的RNA catalysts，包括一些脊髓运动神经病。