Fig 1: Ggnbp2 deletion does not affect synapsis but compromises the repair of meiotic DNA double-strand breaks (DSB). A, Nuclear spreads of spermatocytes stained with antibodies against SYCP1 (red) and SYCP3 (green) show that the assembly and disassembly of the synaptonemal complexes are not affected. B, Chromosome spreads of spermatocytes are stained with antibodies against SYCP3 (red) and ?H2AX (green). Four meiotic stages of spermatocyte, leptotene (lepto), zygotene (zygo), pachytene (pachy) and diplotene (diplo) are presented. D, Chromosome spreads of pachytene spermatocytes are stained with SYCP3 antibody (red), DNA DSB repair protein antibodies RAD51, RAD18 and BRCC36 and a crossover marker MLH1 (green) as indicated. Arrows indicate the XY body stained by ?H2AX, RAD51 and RAD18. C,F, The percentage of pachytene cells with >1 ?H2AX (C) and >1 RAD18 foci (F) are significantly higher in Ggnbp2KO than WT mice, which is calculated from 100 randomly selected pachytene spermatocytes per testis and data are from three 60-d-old testes. E,G,H, The numbers of RAD51 (E), BRCC36 (G) and MLH1 (H) foci counts per pachytene cell are significantly higher in Ggnbp2KO than WT mice, which is counted from 50 randomly selected pachytene spermatocytes per testis and results are from three 60-d-old testes. Data are presented as the mean ± SEM (**P < .01, scale bar = 5 µm)