Figure 2.

Meiotic cohesins are dispensable for DSB formation but not for normal loading of RAD51. (A) Double immunolabeling of SYCP3 and γ-H2AX. In wild-type spermatocytes, γ-H2AX labels the chromatin from leptonema to pachynema when the signal disappears from autosomal chromosomes and remains only on sex body chromatin (not depicted). In the single and dKO-kls mutants, γ-H2AX also labels leptotene chromatin. (B) Double immunolabeling of SYCP3 and RAD51. In wild-type spermatocytes and spermatocytes of single Rad21l or Rec8 mutants, RAD51 localizes to AEs/LEs at leptonema. In Rec8^−/− Rad21l^−/− spermatocytes, there is an 8.5-fold reduction in the number of RAD51 foci. Bars, 100 µm.