Figure 3. Impaired XY body formation in H2ax-Y142A mouse.

(A) Wild-type (WT) littermate control and H2ax-Y142A pachytene spermatocytes on 3D slides (see STAR METHODS) immunostained with antibodies raised against RNAPII and BRCA1. Although not shown in the panel, the spermatocytes were also immunostained with an anti-H1T antibody to determine their stage; the spermatocytes shown are H1T-positive. Dashed circles indicate the sex chromosomes.

(B) WT littermate control and H2ax-Y142A testis sections immunostained with antibodies raised against BRCA1 and H1T. Dashed squares are magnified in the panels to the right. White arrowheads indicate the axes of sex chromosomes in H1T-positive pachytene spermatocytes. Nuclei were counterstained with DAPI. Scale bars: 100 μm and, in the panels to the right, 10 μm.

(C) WT and H2ax-Y142A pachytene spermatocytes on 3D slides immunostained with an antibody raised against BRCA1. Although not shown in the panel, the spermatocytes were also immunostained with an anti-H1T antibody to determine their stage; the spermatocytes shown are H1T-positive. The relative distances are shown in a box-and-whisker plot: The central line is the median, the bottom edge of the box is the first quartile, the top edge of the box is the third quartile, and the whiskers encompass, from top to bottom, the first to ninth decile. Total numbers of analyzed nuclei, obtained from 3 independent wild-type mice and 4 independent H2ax-Y142A mice, are indicated in the panel. **** p < 0.0001, Mann-Whitney U test. Nuclei were counterstained with DAPI. Scale bars: 10 μm.