Fig. 2.

PRDM9 in the nuclei of germ cells during early meiotic prophase I. a-h: Immunolabeling of whole-mounted seminiferous tubules retrieved from mice at 8 dpp; antibodies used recognize KIT (red in b and d), PRDM9 (green in c, d, g and h), and STRA8 (red in f and h). Arrows in b and d denote spermatogonia, and in f and h, the arrows indicate preleptotene spermatocytes. i-l: Seminiferous tubules retrieved from adult mice at stage VII-VIII (i) were immunolabeled with anti-SYCP3 (red in j and l) and anti-PRDM9 (green in k and l). Both SYCP3 (red) and PRDM9 (green) are localized in preleptotene spermatocytes (arrow head in j-l), but PRDM9 (green) is not present in pachytene spermatocytes (arrow in j-l). m-p: Squashed germ cell preparations from adult seminiferous tubules at stage IX-X (m) were immunolabeled with anti-PRDM9 (green in n-p), anti-SYCP3 (red in o and p), and P-H2AFX (pink in p). PRDM9 (green) and SYCP3 (red) are localized in zygotene spermatocytes (arrow head in n-p), but PRDM9 (green) is not present in pachytene spermatocytes (arrow in n-p). Nuclei were counterstained with DAPI in blue (a, d, e, h, l and p). Scale bars = 20 μm