MRM/4930432K21Rik modulates localization of RAD51 and DMC1 to DSBs in meiotic recombination

A meiosis-specific factor MRM/C19orf57/4930432K21Rik modulates localization of RAD51 and DMC1 recombinases to DSBs in mouse meiotic recombination
Kazumasa Takemoto , Naoki Tani , Yuki Takada , Sayoko Fujimura , Nobuhiro Tanno , Mariko Yamane , Kaho Okamura , Michihiko Sugimoto , Kimi Araki and Kei-ichiro Ishiguro

Meiotic recombination is initiated by DNA double-strand break (DSB) followed by multiple processes of DNA repair. The exact mechanisms how recombinases localize to DSB remained elusive. Here we show that MRM/C19orf57/4930432K21Rik is a new player for meiotic recombination in mice. MRM/C19orf57/4930432K21Rik associates with ssDNA binding proteins, BRCA2 and MEILB2/HSF2BP, critical recruiters of recombinases onto DSB sites. Disruption of MRM/C19orf57 shows severe impact on DSB repair and male fertility. Remarkably, removal of single stranded DNA (ssDNA) binding proteins from DSB sites is delayed, and reciprocally the loading of RAD51 and DMC1 onto resected ssDNA is impaired in Mrm KO spermatocytes. We propose that MRM/C19orf57/4930432K21Rik modulates localization of recombinases to meiotic DSB sites through the interaction with the BRCA2-MEILB2/HSF2BP complex during meiotic recombination.