Fig 1: RBMXL2 protein is important for mouse germ cells to progress past diplotene into metaphase I of meiosis.(A) Testis morphologies of adult wild type and homozygous knockout (Rbmxl2-/-) mice (scale above testes shown in millimeters). (B) Testis:body weight ratios of different genotype mice. P values were calculated using a t test. (C) Micrographs of haemotoxylin-stained testis sections from wild type and Rbmxl2-/- mice. Abbreviations: Spg, spermatogonia; Spc, spermatocyte; Rtd, round spermatid; Spd, elongating spermatid. Scale bar = 20 um. (D) Epididymis of wild type and Rbmxl2-/- mice stained with haemotoxylin and eosin. Asterisk indicates lumen (note lumen is empty in Rbmxl2-/- section indicative of azoospermia, but contains multiple cells in the wild type). Scale bar = 20 um. (E) Epididymal sperm counts of wild type and Rbmxl2-/- mice (n = 4 of each genotype). The error bar represents SEM. (F) Meiotic prophase I stages detected in wild type and Rbmxl2-/- testis chromosome spreads stained for SYCP3 (pseudocoloured red) and SYCP1 (pseudocoloured green); and DAPI and SYCP3 (pseudocoloured blue and red respectively). No metaphase I nuclei were identified in the Rbmxl2-/- testes. Quantitative data are provided in Figure 2—figure supplement 2.