Expression and localization of RAD51 during porcine oocyte meiotic maturation. (A) Analysis of RAD51 mRNA levels during porcine oocyte meiosis by RT-qPCR. The mRNA levels of RAD51 at the GV, GVBD, MI, and MII stages were ± 100, ± 42, ± 98.27, and ± 192.33%, respectively. The normalized expression of RAD51 was quantified and is reported as the mean ± SEM from three independent experiments. * P < 0.05. *** P < 0.001. (B) Immunostaining of RAD51 during porcine oocyte meiotic maturation. Hoechst33342 was used for DNA counterstaining. Oocytes were collected at 0, 24, 30, and 44 h of incubation (corresponding to the GV, GVBD, meiosis I, and meiosis II stages, respectively). Red, RAD51; blue, DNA. Scale bar = 20 μm.