Chromatin organization in the C. elegans germline is tightly regulated and critical for germ cell differentiation. Although certain germline epigenetic regulatory mechanisms have been identified, how they influence chromatin structure and ultimately gene expression remains unclear, in part because most genomic studies have focused on data collected from intact worms comprising both somatic and germline tissues. We therefore analyzed histone modification and chromatin accessibility data from isolated germ nuclei representing undifferentiated proliferating and meiosis I populations to define chromatin states. We correlated these states with overall transcript abundance, spatiotemporal expression patterns, and the function of small RNA pathways. Because the essential role of the germline is to transmit genetic information and establish gene expression in the early embryo, we compared epigenetic and transcriptomic profiles from undifferentiated germ cells to those of embryos to define the epigenetic changes during this developmental transition. The active histone modification H3K4me3 shows particularly dynamic remodeling as germ cells differentiate into oocytes, which suggests a mechanism for establishing early transcription of essential genes during zygotic genome activation. This analysis highlights the dynamism of the chromatin landscape across developmental transitions and provides a resource for future investigation into epigenetic regulatory mechanisms in germ cells.

中文翻译：

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秀丽隐杆线虫种系中染色质状态的分布和动态特征揭示了卵子发生过程中 H3K4me3 的大量重塑

线虫种系中的染色质组织受到严格调控，对于生殖细胞分化至关重要。尽管某些种系表观遗传调控机制已被确定，但它们如何影响染色质结构和最终基因表达仍不清楚，部分原因是大多数基因组研究都集中在从包含体细胞和种系组织的完整蠕虫中收集的数据。因此，我们分析了来自代表未分化增殖和减数分裂 I 群体的分离胚核的组蛋白修饰和染色质可及性数据，以定义染色质状态。我们将这些状态与总体转录本丰度、时空表达模式和小 RNA 通路的功能相关联。由于种系的重要作用是在早期胚胎中传递遗传信息并建立基因表达，因此我们将未分化生殖细胞与胚胎的表观遗传和转录组谱进行比较，以定义这一发育转变期间的表观遗传变化。当生殖细胞分化为卵母细胞时，活性组蛋白修饰 H3K4me3 显示出特别动态的重塑，这表明在合子基因组激活过程中建立必需基因早期转录的机制。该分析强调了染色质景观在整个发育转变过程中的活力，并为未来研究生殖细胞表观遗传调控机制提供了资源。