Insight into meiotic DNA end resection: Mechanisms and regulation

Meiosis generates reproductive cells with a reduced genome complement, with most species using homologous recombination to promote accurate meiotic chromosome segregation and to generate genetic diversity among offspring. A critical step in homologous recombination is DNA end resection, in which DNA double-strand breaks (DSBs) are processed by nucleases to yield the 3' single-stranded DNA (ssDNA) needed for homology search and strand invasion. DSB resection in nonmeiotic contexts has been extensively studied, but meiotic resection is less well understood. We provide here a review of studies elucidating the mechanism and regulation of resection during meiosis, covering similarities and differences from resection in mitotically dividing cells. The nucleases that carry out resection are discussed, along with resection-modulating factors such as DNA damage signaling and chromatin structure. We focus on the budding yeast Saccharomyces cerevisiae and on mouse, for which the most information is currently available, but also describe studies in other species that point to evolutionary conservation or divergence in this key process needed for genome integrity in the germline.