Meiotic recombination proceeds via binding of RPA, RAD51, and DMC1 to single-stranded DNA (ssDNA) substrates created after formation of programmed DNA double-strand breaks. Here we report high-resolution in vivo maps of RPA and RAD51 in meiosis, mapping their binding locations and lifespans to individual homologous chromosomes using a genetically engineered hybrid mouse. Together with high-resolution microscopy and DMC1 binding maps, we show that DMC1 and RAD51 have distinct spatial localization on ssDNA: DMC1 binds near the break site, and RAD51 binds away from it. We characterize inter-homolog recombination intermediates bound by RPA in vivo, with properties expected for the critical displacement loop (D-loop) intermediates. These data support the hypothesis that DMC1, not RAD51, performs strand exchange in mammalian meiosis. RPA-bound D-loops can be resolved as crossovers or non-crossovers, but crossover-destined D-loops may have longer lifespans. D-loops resemble crossover gene conversions in size, but their extent is similar in both repair pathways.
Journal article
2020-08-20T00:00:00+00:00
79
689 - 701.e10
D-loop, DMC1, DNA double-strand breaks, DNA repair, RAD51, RPA, crossover, meiosis, recombination, strand invasion, Animals, Cell Cycle Proteins, Chromosomes, Crossing Over, Genetic, DNA, Single-Stranded, Genome, Homologous Recombination, Male, Meiosis, Mice, Inbred C57BL, Mice, Inbred DBA, Phosphate-Binding Proteins, Rad51 Recombinase, Replication Protein A, Testis