Figure 2. Transcriptional silencing of the pseudo XY body in spermatocytes and oocytes.

(A–B) Double immunostaining with anti-γH2AX and anti-RNA polymerase II of spermatocyte (A) and oocyte (B) nuclei from Spo11^−/− (A, upper panel), Spo11^YF/YF (A–B, lower panels), and Spo11^+/+ (B, upper panel) animals. Nuclear domains enriched in γH2AX are marked by a dashed circle. (C) Scatter plots of the relative amount of RNA polII in a γH2AX domain normalized to the RNA polII level in a non-heterochromatic area of the same nucleus. Every dot represents a nucleus. RNA polII levels are compared between γH2AX domains (pseudo XY body) of Spo11^+/+ and Spo11^YF/YF E17.5 oocytes, and the proper sex body in Spo11^+/+ mid-pachytene spermatocytes. Grey lines indicate the average. No significant difference between the wild type pachytene spermatocyte nuclei and either E17.5 oocyte nuclei group was observed (Mann-Whitney, confidence interval p<0.01).