Spatiotemporal Regulation of Liquid-like Condensates in the Germline

种系中液体状凝聚物的时空调节

基本信息

批准号：
10361464
负责人：
Scott G Kennedy
金额：
$ 36.16万
依托单位：
HARVARD MEDICAL SCHOOL
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-06-01 至 2023-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10361464
关键词：
Adult Animals Architecture Binding Biochemical Pathway Biochemical Reaction Biogenesis Biological Models Caenorhabditis elegans Cell physiology Cells Complex Cytoplasm Cytoplasmic Granules Development Double-Stranded RNA Ensure Epigenetic Process Eukaryotic Cell Gene Expression Regulation Gene Silencing Generations Genes Genetic Screening Germ Germ Cells Goals Inherited Liquid substance Mammals Mediating Mediator of activation protein Messenger RNA MicroRNAs Modeling Nucleoplasm Oils Organelles Parents Pathway interactions Phase Transition Plants Play Positioning Attribute Process Proteins RNA RNA Interference RNA Processing RNA interference screen RNA-Binding Proteins Regulation Regulator Genes Role Signal Transduction Small Interfering RNA Structure System Technology Time Totipotency Transfer RNA Untranslated RNA Water embryo stage 2 mutant offspring piRNA spatiotemporal trafficking trait transgenerational epigenetic inheritance

项目摘要

SUMMARY/ABSTRACT Liquid droplet organelles (also referred to as liquid-like condensates) are dynamic concentrations of protein and RNA that coalesce spontaneously from the cytoplasm or nucleoplasm via liquid-liquid phase transition. Like oil and water, these liquid droplets and their surrounding cytoplasm are thought to co-exist as separate states of liquid. Current models posit that liquid droplet organelles may exist to concentrate reactants together in space and time in ways that facilitate biochemical reactions such as the complexes processes that underlie gene regulation. Eukaryotic cells possess many non-membrane-enclosed liquid droplet organelles including nucleoli, processing bodies, cajal bodies and germ granules. Germ granules are found in the germ cells of all/most animals where they are thought to contribute to germ cell totipotency. Indeed, orthologous proteins (e.g. VASA) are found in germ granules of many different species of animals, hinting that some aspects of germ granule function may be conserved in all animals. Most epigenetic information is erased at or near the start of each new generation in animals to ensure totipotency of the germline. In some cases, epigenetic information escapes reprogramming and is passed from parent to offspring. The inheritance of epigenetic information for more than one generation is termed trans- generational epigenetic inheritance (TEI). Small non-coding RNAs (e.g. siRNAs, miRNAs, piRNAs, and tRNA fragments) have emerged as important mediators of TEI (cumulatively, RNA-directed TEI). dsRNA-mediated gene silencing (RNAi) in C. elegans is a robust and dramatic example of RNA-directed TEI. My lab is using RNAi inheritance in C. elegans as a model system to explore how epigenetic signals are passed across generations in animals. We recently conducted a genetic screen for RNAi inheritance factors that identified two conserved RNA binding proteins (RBPs). These RBPs contribute directly to inheritance by helping to maintain the expression of silencing RNAs over generations during RNAi inheritance. Interestingly, both RBPs localize to a new C. elegans germ granule whose biogenesis is developmentally regulated and whose positioning relative to other germline condensates is highly ordered. Finally, we find that the two RNAi inheritance factors we have identified are required for maintaining germline immortality. Together, our results have led us to propose that the temporal and spatial ordering of liquid droplet organelles may help germ cells organize and coordinate the complex RNA processing pathways underlying gene regulatory systems, such as RNA-directed TEI and germline immortality. This proposal outlines our efforts to further understand how liquid-like condensates form during development, how they assemble into complex structures with other germline condensates, and, most importantly, why they do so.

摘要/摘要液滴细胞器（也称为液状冷凝物）是动态浓度的蛋白质和RNA通过液态液相自发地从细胞质或核质中融合过渡。像油和水一样，这些液滴及其周围的细胞质被认为是共存的单独的液体状态。当前模型认为可能存在液滴细胞器来浓缩反应物在空间和时间上以促进生化反应的方式一起进行，例如复合物过程基因调节基础。真核细胞具有许多非膜封闭的液滴细胞器包括核仁，加工体，cajal体和细菌颗粒。细菌颗粒在细菌中发现所有/大多数动物的细胞被认为会导致生殖细胞全能。确实，直系同源蛋白质（例如VASA）在许多不同动物种类的细菌颗粒中发现，暗示某些方面在所有动物中都可以保留生殖颗粒功能。大多数表观遗传信息在每个新一代动物的开始或附近都被删除，以确保种系的全能。在某些情况下，表观遗传信息逃脱了重编程，并从父母的后代。超过一代的表观遗传信息的继承称为反式世代表观遗传遗传（TEI）。小型非编码RNA（例如siRNA，miRNA，PIRNA和tRNA 片段已成为TEI的重要介质（累积的RNA定向TEI）。 DSRNA介导的秀丽隐杆线虫中的基因沉默（RNAi）是RNA定向TEI的强大而戏剧性的例子。我的实验室正在使用RNAi 秀丽隐杆线虫的继承是一种模型系统，以探讨如何通过世代传递表观遗传信号在动物中。我们最近对RNAi遗传因子进行了遗传筛选，该因子鉴定了两个保守 RNA结合蛋白（RBP）。这些RBP通过帮助维护在RNAi遗传过程中，沉默的RNA的表达。有趣的是，两个RBP都本地化新的秀丽隐杆线虫生物颗粒的生物发生在发育中受到调节，其定位相对于其他种系冷凝水是高度排序的。最后，我们发现我们拥有的两个RNAi遗传因素确定维持种系永生所需的必要。一起，我们的结果使我们提出了液滴器细胞器的时间和空间顺序可以帮助生殖细胞组织和坐标复杂的RNA处理途径基因调节系统，例如RNA定向TEI和种系不朽。该提议概述了我们为进一步了解液体状冷凝物在期间的形成方式的努力开发，如何与其他种系冷凝物组装成复杂的结构，大多数重要的是，他们为什么这样做。