Evidence of DNA/RNA hybrids (R-loops) accumulation in spermatocytes of ARCA mouse model.

<p><b>A.</b> Histological cross-sections of seminiferous tubules from ARCA mouse models <i>Setx^−/−</i>, <i>Atm^−/−</i>, <i>Aptx^−/−</i>, <i>Tdp1^−/−</i> and wildtype (WT) littermates. Sections were H & E stained. Scale bar, 100 µm. <b>B.</b> Immunostaining of testes sections with R-loop (S9.6) antibody (red) and TUNEL (green). Nuclei were stained using Hoechst 33342 (blue). Scale bar, 100 µm. Magnified views of the tubules are also shown. Representative spermatocytes staining positive for both R-loop and TUNEL are indicated by white arrows. <b>C.</b> Immunostaining of testes sections with γH2AX (red), a marker of DNA DSBs, and TUNEL (green). Scale bar, 100 µm.