Spread wild type mouse spermatocyte nuclei immunostained for CHD3/4 (green), SYCP3 (red), and counterstained with DAPI (blue). In wild type spermatocytes, CHD3/4 is most enriched on some ends of axial elements in zygotene (white arrows), then mainly on the pseudoautosomal region (PAR, P) in early (e) pachytene (see also enlargements at the bottom). Subsequently, all XY chromatin is somewhat enriched in mid (m) pachytene, followed by more specific restriction to the par and the X centromere in late (l) pachytene (enlargement on the bottom of the middle panel). In early and late diplotene, CHD4 enrichment is observed on centromeric heterochromatin, and more evenly distributed on the XY body (enlargement on the bottom of the right panel). XY bodies are indicated with dashed rectangles in the images. In the enlargements, X and Y indicate the axes corresponding to the X and Y chromosome, respectively.