RNA-DNA hybrids regulate meiotic recombination

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. [Display omitted] •RNA-DNA hybrids form at ssDNA ends of meiotic DNA double-strand break sites•Formation of meiotic RNA-DNA hybrids requires Rad52•RNA-DNA hybrids regulate the homolog bias in meiotic recombination•RNA-DNA hybrids modulate both crossover and non-crossover recombination The role of RNA-DNA hybrids in DNA damage repair remains unclear. Yang et al. reveal RNA-DNA hybrids form at ssDNA ends of DNA double-strand breaks to regulate both crossover and non-crossover recombination via affecting homolog bias during meiosis. The results demonstrate RNA-DNA hybrids actively regulate meiotic recombination.