Figure 9.

Double-strand break (DSB) formation. (A) Before DSB formation, Trem localizes to the chromosomes and is required for the recruitment of Mei-P22 to discreet foci. Mei-W68 and Vilya are recruited to sites of Mei-P22, leading to the formation of DSBs. (B) Without Trem, Mei-P22 localizes along chromosome arms rather than to discreet foci. Without either Mei-P22 or Mei-W68, Trem still localizes to chromosome arms, but Vilya does not form discreet foci. If any of these proteins are missing, DSBs are not made. Adapted from Lake et al. (2015). CO, crossover; NCO, noncrossover.