RPA1 is required for pre-meiotic S-phase DNA replication in preleptotene spermatocytes.

Pulse labelling of DNA replicating cells was performed with intraperitoneal injection of BrdU. (A) Immunofluorescence analysis of BrdU incorporation in stage VII-VIII seminiferous tubules. The acrosome morphology shown by SP10 immunofluorescence was used for seminiferous tubule staging. All positive tubule: all preleptotene spermatocytes are BrdU-positive; All negative tubule: all preleptotene spermatocytes are BrdU-negative; Partial positive tubule: a fraction of preleptotene spermatocytes are BrdU-positive; Pre-lep loss tubule: absence of preleptotene spermatocytes in stage VII-VIII seminiferous tubules. (B) Percentage of two types of stage VII-VIII tubules in control mice. (C) Percentage of four types of stage VII-VIII tubules from Rpa1cKO at 0 day post-tamoxifen treatment. (B, C) Three pairs of control and Rpa1cKO males (0 day post tamoxifen treatment) were analyzed. At least thirty five stage VII-VIII tubules were counted for each mouse.