Department and College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan.
Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Kweishan, Taoyuan 333 Taiwan.
Genome Res. 2021 Jun;31(6):1011-1023. doi: 10.1101/gr.271148.120. Epub 2021 Apr 15.
Germ cells in are specified maternally shortly after fertilization and are transcriptionally quiescent until their zygotic genome is activated to sustain further development. To understand the molecular basis of this process, we analyzed the progressing transcriptomes of early male and female germ cells at the single-cell level between germline specification and coalescence with somatic gonadal cells. Our data comprehensively cover zygotic activation in the germline genome, and analyses on genes that exhibit germline-restricted expression reveal that polymerase pausing and differential RNA stability are important mechanisms that establish gene expression differences between the germline and soma. In addition, we observe an immediate bifurcation between the male and female germ cells as zygotic transcription begins. The main difference between the two sexes is an elevation in X Chromosome expression in females relative to males, signifying incomplete dosage compensation, with a few select genes exhibiting even higher expression increases. These indicate that the male program is the default mode in the germline that is driven to female development with a second X Chromosome.
生殖细胞在受精后不久就由母体特异性决定，并在其合子基因组被激活以维持进一步发育之前处于转录沉默状态。为了理解这一过程的分子基础，我们在生殖细胞与体生殖细胞融合之前，在单细胞水平上分析了早期雄性和雌性生殖细胞的进行性转录组。我们的数据全面涵盖了合子基因组中的激活，对表现出生殖细胞特异性表达的基因的分析表明，聚合酶暂停和差异 RNA 稳定性是在生殖细胞和体之间建立基因表达差异的重要机制。此外，我们观察到随着合子转录的开始，雄性和雌性生殖细胞立即发生分叉。两性之间的主要区别是雌性 X 染色体的表达升高，相对于雄性，表明不完全剂量补偿，少数精选基因表现出更高的表达增加。这表明雄性程序是生殖细胞的默认模式，在第二个 X 染色体的驱动下向雌性发育。
