Fig. 4: Impaired meiotic recombination in Stra8-Trf1^−/− spermatocytes

a Trf1^Flox/Flox and Stra8-Trf1^−/− chromosome spreads of spermatocytes were immunostained with antibodies against SYCP3 (green) and γH2AX (red). γH2AX marked DSBs in leptotene and zygotene spermatocytes. No difference was observed between Trf1^Flox/Flox and Stra8-Trf1^−/− at these stages. In the Trf1^Flox/Flox spermatocytes at the pachytene stage, DSBs were mostly repaired and γH2AX was confined to the XY body, whereas at the pachytene-like stage in Stra8-Trf1^−/− spermatocytes, γH2AX remained on some of the autosomal regions. b Trf1^Flox/Flox and Stra8-Trf1^−/− chromosome spreads of spermatocytes were immunostained with antibodies against SYCP3 (green) and ATR (red). In the Trf1^Flox/Flox spermatocytes at the pachytene stage, DSBs were mostly repaired and ATR was confined to the XY body, while the ATR signal persisted on the autosomes in Stra8-Trf1^−/− spermatocytes. c Trf1^Flox/Flox and Stra8-Trf1^−/− chromosome spreads of spermatocytes were immunostained with antibodies against SYCP3 (green) and DMC1 (red). The DMC1 signals were dramatically increased in the Stra8-Trf1^−/− spermatocytes at the zygotene stage compared with those in the Trf1^Flox/Flox spermatocytes. d Trf1^Flox/Flox and Stra8-Trf1^−/− chromosome spreads of spermatocytes were immunostained with antibodies against SYCP3 (green) and MLH1 (red). MLH1 is a recombination marker in WT spermatocytes and decreased MLH1 staining was observed in Stra8-Trf1^−/− spermatocytes. e MLH1 signals were counted in spreads. Quantification of the MLH1 foci numbers per cell in the Trf1^Flox/Flox and Stra8-Trf1^−/− spermatocytes. Trf1^Flox/Flox, 25.0 ± 1.7; Stra8-Trf1^−/−, 10.6 ± 2.8. Data are presented as mean ± SEM. ***P < 0.001.