Fig. 5. Cohesin distribution and centromere cohesion at MI is unaffected in Sycp3^–/– spermatocytes. Cells from wild-type (A,B,J) or Sycp3^–/– (C-I,K-M) testes were treated with okadaic acid. Spermatocytes at MI were stained with DAPI (A,C,E,H), or an anti-STAG3 antibody (B,D,M), anti-REC8 antibody (F), anti-SMC1ß antibody (I), anti-SYCP2 antibody (J,K) and anti-CREST (B,D,F,I-K,M). Wild-type MI spermatocytes exhibit 20 bivalents with paired (single) centromeres (B, arrowheads). Sycp3^–/– MI spermatocytes have 40 univalents with paired centromeres (D,F,I, arrowheads). SYCP2 fails to accumulate at the centromeres in the absence of SYCP3 (K). Mitotic cells (L,M) derived from Sycp3^–/– testes (negative for STAG3) show separated centromere pairs (M, arrows). Bars, 10 µm.