Fig. 2.

Loss of DGCR8 or DICER results in chromosomal fusion abnormalities. (A–I) Pachytene stage spermatocytes from wild-type (A,D,G) Dgcr8 cKO (B,E,H) or Dicer cKO (C,F,I) mice, each stained with anti-SYCP3 antibody (green). XY chromosomes are indicated by white arrows. Immunostaining was also performed with antibodies specific to SYCP1 and CREST, a human autoimmune serum used to visualize centromeres (A–C, red and purple, respectively), γH2AX (D–F, red), and RNAP II (G–I, red). (J) Dgcr8 cKO and Dicer cKO spermatocytes exhibit frequent chromosomal abnormalities. Chromosome spread preparations of pachytene stage spermatocytes were assessed for the types and frequencies of observed abnormalities, none of which were ever observed in wild-type pachytene spermatocytes. These were distributed into five indicated categories based on observed frequencies of X and Y chromosomal structures.