State Key Laboratory of Reproductive Medicine and Offspring Health, Changzhou Maternity and Child Health Care Hospital, Changzhou Medical Center, Nanjing Medical University, 101 Longmian Rd, Nanjing, 211166, China.
Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China.
J Ovarian Res. 2024 Jan 24;17(1):23. doi: 10.1186/s13048-023-01342-8.
In fully grown oocytes, the genome is considered to be globally transcriptionally silenced. However, this conclusion is primarily derived from the results obtained through immunofluorescence staining or inferred from the highly condensed state of chromosomes, lacking more direct evidence. Here, by using a kethoxal-assisted single-stranded DNA sequencing (KAS-seq) approach, we investigated the landscape of single-strand DNA (ssDNA) throughout the genome and provided a readout of the activity and dynamics of transcription during oocyte meiotic maturation. In non-surrounded nucleolus (NSN) oocytes, we observed a robust KAS-seq signal, indicating the high transcriptional activity. In surrounded nucleolus (SN) oocytes, the presence of ssDNA still persists although the KAS-seq signal was relatively weak, suggesting the presence of transcription. Accompanying with the meiotic resumption, the transcriptional activity gradually decreased, and global repression was detected in matured oocytes. Moreover, we preformed the integrative genomics analysis to dissect the transcriptional dynamics during mouse oocyte maturation. In sum, the present study delineates the detailed transcriptional activity during mammalian oocyte maturation.
在完全成熟的卵母细胞中，基因组被认为是全局转录沉默的。然而，这一结论主要是根据免疫荧光染色的结果得出的，或者是从染色体的高度浓缩状态推断出来的，缺乏更直接的证据。在这里，我们通过使用亚硝酮辅助的单链 DNA 测序（KAS-seq）方法，研究了整个基因组中单链 DNA（ssDNA）的图谱，并提供了卵母细胞减数分裂成熟过程中转录活性和动力学的读数。在非包围核仁（NSN）卵母细胞中，我们观察到了强大的 KAS-seq 信号，表明转录活性很高。在包围核仁（SN）卵母细胞中，尽管 KAS-seq 信号相对较弱，但仍存在 ssDNA，表明存在转录。伴随着减数分裂的恢复，转录活性逐渐降低，在成熟卵母细胞中检测到全局抑制。此外，我们进行了整合基因组学分析，以剖析小鼠卵母细胞成熟过程中的转录动力学。总之，本研究描绘了哺乳动物卵母细胞成熟过程中的详细转录活性。
