European Molecular Biology Laboratory, European Bioinformatics Institute, (EMBL-EBI), Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
University of Cambridge, Cancer Research UK Cambridge Institute, Robinson Way, Cambridge, CB2 0RE, UK.
Nat Commun. 2019 Mar 19;10(1):1251. doi: 10.1038/s41467-019-09182-1.
Male gametes are generated through a specialised differentiation pathway involving a series of developmental transitions that are poorly characterised at the molecular level. Here, we use droplet-based single-cell RNA-Sequencing to profile spermatogenesis in adult animals and at multiple stages during juvenile development. By exploiting the first wave of spermatogenesis, we both precisely stage germ cell development and enrich for rare somatic cell-types and spermatogonia. To capture the full complexity of spermatogenesis including cells that have low transcriptional activity, we apply a statistical tool that identifies previously uncharacterised populations of leptotene and zygotene spermatocytes. Focusing on post-meiotic events, we characterise the temporal dynamics of X chromosome re-activation and profile the associated chromatin state using CUT&RUN. This identifies a set of genes strongly repressed by H3K9me3 in spermatocytes, which then undergo extensive chromatin remodelling post-meiosis, thus acquiring an active chromatin state and spermatid-specific expression.
精子是通过一种专门的分化途径产生的，该途径涉及一系列发育转变，这些转变在分子水平上的特征描述很差。在这里，我们使用基于液滴的单细胞 RNA 测序来描述成年动物和幼年发育过程中多个阶段的精子发生。通过利用第一次精子发生，我们精确地对精母细胞发育进行分期，并富集稀有体细胞类型和精原细胞。为了捕捉包括转录活性低的细胞在内的精子发生的全部复杂性，我们应用了一种统计工具，该工具可以识别以前未表征的细线期和合线期精母细胞群体。我们专注于减数分裂后事件，描述 X 染色体重新激活的时间动态，并使用 CUT&RUN 对相关染色质状态进行分析。这确定了一组在精母细胞中被 H3K9me3 强烈抑制的基因，这些基因在减数分裂后经历广泛的染色质重塑，从而获得活跃的染色质状态和精细胞特异性表达。
