Regulation paternaler Vererbung eines Argonaute Proteins in C. elegans

有性繁殖需要生殖细胞的形成，这是一种致力于混合两个个体的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，即减数分裂，这会降低生殖细胞的倍性。减数分裂还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。异性配子随后可以融合并产生受精卵，该受精卵可以成长为新的个体。因此，新的个体拥有来自父母双方的染色体形式的遗传信息。然而，除了DNA，受精卵还继承了许多对进一步发育至关重要的额外细胞成分。这些成分的母性贡献可以预计会超过父性贡献，原因很简单，因为卵母细胞(女性配子)比精子(男性配子)大得多。事实上，母性遗传是线虫发育的一个众所周知的方面，许多所谓的“母性效应”基因已经通过基因筛查得到识别。然而，父系遗传材料也对受精卵有显著影响。例如，肥胖或营养不良可以在小鼠的父系中传播，已经观察到tRNA片段和miRNAs通过精子传播并对功能产生影响。这种父系遗传尤其引人注目，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过程，将该分子保留在成熟的精子细胞中。在这项研究提案中，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的蛋白质从成熟的精子细胞中排出，从而使其保持在成熟精子中。WAGO-3是一种所谓的ArgAerte蛋白，它与一种小RNA辅助因子结合，需要调节基因表达。它通过精子传递到胚胎中与胚胎具有功能相关性，PEI-1对它的调节代表着以小RNA的形式跨代传递染色体外信息的重要一步。所描述的研究主要旨在破译PEI-1和WAGO-3是如何相互作用的，以及这种相互作用如何在精子发生期间保存WAGO-3。此外，拟议的实验将阐明如何在不同的相分离结构中发现WAGO-3，这取决于发育状态及其携带小RNA辅助因子的情况。

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.