Antagonistic roles of ubiquitin ligase HEI10 and SUMO ligase RNF212 regulate meiotic recombination

Abstract

Crossover recombination facilitates accurate segregation of homologous chromosomes during meiosis ^{1, 2} . In mammals, poorly characterized regulatory processes ensure every pair of chromosomes obtains at least one crossover, even though the majority of recombination sites yield non-crossovers ³ . Designation of crossovers involves selective localization of SUMO-ligase RNF212 to a minority of recombination sites where it stabilizes pertinent factors, such as MutSγ ⁴ . Here we show ubiquitin-ligase HEI10/CCNB1IP1 ^{5, 6} is essential for this crossover/non-crossover differentiation process. In Hei10 mutant mice, RNF212 localizes to most recombination sites and dissociation of RNF212 and MutSγ from chromosomes is blocked. Consequently, recombination is impeded and crossing-over fails. In wild-type mice, HEI10 accumulates at designated crossover sites suggesting a late role to implement crossing-over. Like RNF212 , dosage-sensitivity indicates HEI10 is a limiting factor for crossing-over. We suggest SUMO and ubiquitin play antagonistic roles during meiotic recombination that are balanced to effect differential stabilization of recombination factors at crossover and non-crossover sites.