Meiotic Defects in Trip13Gt/Gt Oocytes Are DSB-Dependent
Epistasis analysis of females was insightful with respect to the cause of arrest in Trip13 mutants. Both Mei1 −/−/Trip13Gt/Gt and Spo11 −/−/Trip13Gt/Gt females had ovaries with numerous follicles, identical to Mei1 and Spo11 single mutants (Figure 3O–3R). Thus, Spo11 and Mei1 are epistatic to Trip13 in oogenesis, just as they are to Dmc1 [13,41]. This demonstrates that oocyte loss in Trip13Gt/Gt females is dependent on DSB formation. In conjunction with the immunohistochemical data, these data provide strong evidence that meiotic arrest in Trip13 mutant mice is due to defects in DSB repair. As expected, ovaries of Rec8 Trip13 double mutants were devoid of oocytes as were those from either single mutant (Figure 3B, 3S, and 3T).