Regulation paternaler Vererbung eines Argonaute Proteins in C. elegans

有性生殖需要生殖细胞的形成，生殖细胞是一种致力于混合两个个体遗传信息的细胞类型。为此，生殖细胞经历一种特殊类型的细胞分裂，减数分裂，降低生殖细胞的倍性。减数分裂也伴随着广泛的细胞分化，导致高度分化的成熟生殖细胞，称为配子。异性的配子随后可以融合并产生一个受精卵，受精卵可以长成一个新的个体。因此，新的个体具有遗传信息，以染色体的形式，来自父母双方。然而，除了DNA，受精卵还遗传了许多对进一步发育至关重要的额外细胞成分。可以预期，母体对这些成分的贡献将超过父体的贡献，这仅仅是因为卵母细胞（雌性配子）比精子（雄性配子）大得多。事实上，母系遗传是C.许多所谓的“母亲效应”基因已经通过基因筛选被鉴定出来。然而，父系遗传物质也显著影响受精卵。例如，肥胖或营养不良可以沿着小鼠的父系血统传播，并且已经观察到tRNA片段和miRNA通过精子传播并具有功能影响。这种父系遗传特别引人注目，因为精子发生通常与大量细胞内容物的挤出有关。因此，任何特定分子的父系遗传都可能需要一个将该分子保留在成熟精子中的过程。在这项研究计划中，我描述了我们最近发现的一种新型的相分离结构，由蛋白质PEI-1定义。这种蛋白质需要保护一种名为WAGO-3的蛋白质免受成熟精子细胞的挤压，从而将其保持在成熟精子中。WAGO-3是一种所谓的argonaute蛋白，与小RNA辅因子结合，是调节基因表达所必需的。它通过精子传递到胚胎中与胚胎具有功能相关性，并且PEI-1对其的调节代表了染色体外信息以小RNA形式跨代传递的重要步骤。所描述的研究主要旨在破译PEI-1和WAGO-3如何相互作用，以及这种相互作用如何在精子发生过程中保留WAGO-3。此外，拟议的实验将阐明WAGO-3是如何在不同的阶段分离的结构中发现的，这取决于发育状态及其与小RNA辅因子的负载。

Sexual reproduction requires the formation of germ cells, a cell type dedicated to the mixing of genetic information of two individuals. To do so, germ cells undergo a specialized type of cell division, meiosis, that reduces the ploidy of the germ cell. Meiosis is also accompanied by extensive cellular differentiation, resulting in highly differentiated, mature germ cells, called gametes. Gametes of opposite sexes can subsequently fuse and generate a zygote that can grow into a new individual. As a result, the new individual has genetic information, in the form of chromosomes, from both parents. However, next to DNA, the zygote also inherits many additional cellular components that are of key importance for further development. Maternal contribution of such components can be expected to dominate paternal contribution, simply because the oocyte, the female gamete, is much bigger than sperm, the male gamete. Indeed, maternal inheritance is a well-known aspect of development in C. elegans, and many so-called ‘maternal-effect’ genes have been identified through genetic screens. However, also paternally inherited material significantly influences the zygote. For instance, obesity or undernourishment can be transmitted along the paternal linage in mice and tRNA fragments and miRNAs have been observed to be transmitted through sperm and to have functional impact. Such paternal inheritance is particularly striking, since spermatogenesis typically is associated with the extrusion of significant amounts of the cellular contents. Hence, paternal inheritance of any specific molecule likely requires a process that retains that molecule in the maturing sperm cell. In this research proposal, I describe our recent identification of a novel type of phase-separated structure, defined by the protein PEI-1. This protein is required to protect a protein named WAGO-3 from extrusion from the maturing sperm cell, and thereby maintain it within mature sperm. WAGO-3 is a so-called argonaute protein that, bound with a small-RNA co-factor, is required to regulate gene expression. Its transmission into the embryo via sperm has functional relevance to the embryo, and its regulation by PEI-1 represents an important step in the transmission of extrachromosomal information, in the form of small RNAs, across generations. The described studies primarily aim to decipher how PEI-1 and WAGO-3 interact and how this interaction preserves WAGO-3 during spermatogenesis. In addition, the proposed experiments will shed light on how WAGO-3 is found in different phase-separated structures depending on developmental state and its loading with a small-RNA cofactor.