REC114 partner ANKRD31 controls number, timing and location of meiotic DNA breaks

Double-strand breaks (DSBs) initiate the homologous recombination that is crucial for meiotic chromosome pairing and segregation. Here we unveil mouse ANKRD31 as a lynchpin governing multiple aspects of DSB formation. Spermatocytes lacking ANKRD31 have altered DSB locations and fail to target DSBs to sex chromosomes pseudoautosomal regions (PAR). They also have delayed/fewer recombination sites but, paradoxically, more DSBs, suggesting DSB dysregulation. Unrepaired DSBs and pairing failures--stochastic on autosomes, nearly absolute on X and Y--cause meiotic arrest and sterility in males. Ankrd31-deficient females have reduced oocyte reserves. A crystal structure defines direct ANKRD31- REC114 molecular contacts and reveals a surprising pleckstrin homology domain in REC114. In vivo, ANKRD31 stabilizes REC114 association with the PAR and elsewhere. Our findings inform a model that ANKRD31 is a scaffold anchoring REC114 and other factors to specific genomic locations, promoting efficient and timely DSB formation but possibly also suppressing formation of clustered DSBs.