Center for Reproductive Medicine, Cheeloo College of Medicine, State Key Laboratory of Microbial Technology, Shandong University, China.
Center for Reproductive Medicine, Cheeloo College of Medicine, State Key Laboratory of Microbial Technology, Shandong University, China; National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, Shandong 250012, China; Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China; Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, Shandong 250012, China; Shandong Key Laboratory of Reproductive Medicine, Jinan, Shandong 250012, China.
Cell Rep. 2021 Dec 7;37(10):110097. doi: 10.1016/j.celrep.2021.110097.
RNA-DNA hybrids are often associated with genome instability and also function as a cellular regulator in many biological processes. In this study, we show that accumulated RNA-DNA hybrids cause multiple defects in budding yeast meiosis, including decreased sporulation efficiency and spore viability. Further analysis shows that these RNA-DNA hybrid foci colocalize with RPA/Rad51 foci on chromosomes. The efficient formation of RNA-DNA hybrid foci depends on Rad52 and ssDNA ends of meiotic DNA double-strand breaks (DSBs), and their number is correlated with DSB frequency. Interestingly, RNA-DNA hybrid foci and recombination foci show similar dynamics. The excessive accumulation of RNA-DNA hybrids around DSBs competes with Rad51/Dmc1, impairs homolog bias, and decreases crossover and noncrossover recombination. Furthermore, precocious removal of RNA-DNA hybrids by RNase H1 overexpression also impairs meiotic recombination similarly. Taken together, our results demonstrate that RNA-DNA hybrids form at ssDNA ends of DSBs to actively regulate meiotic recombination.
RNA-DNA 杂交体通常与基因组不稳定性有关，在许多生物学过程中也作为细胞调节剂发挥作用。在这项研究中，我们表明，积累的 RNA-DNA 杂交体导致芽殖酵母减数分裂中的多种缺陷，包括孢子形成效率降低和孢子活力下降。进一步的分析表明，这些 RNA-DNA 杂交体焦点与染色体上的 RPA/Rad51 焦点共定位。RNA-DNA 杂交体焦点的有效形成取决于 Rad52 和减数分裂 DNA 双链断裂 (DSB) 的 ssDNA 末端，其数量与 DSB 频率相关。有趣的是，RNA-DNA 杂交体焦点和重组焦点表现出相似的动态。DSB 周围过多的 RNA-DNA 杂交体积累会与 Rad51/Dmc1 竞争，损害同系物偏向，并减少交叉和非交叉重组。此外，通过过量表达 RNase H1 过早去除 RNA-DNA 杂交体也会类似地损害减数分裂重组。总之，我们的结果表明，RNA-DNA 杂交体在 DSB 的 ssDNA 末端形成，以主动调节减数分裂重组。
