Detection of RNA:DNA hybrid structure in SMA-like mice. (A) Staining result of the RNA:DNA hybrid structure, R-loop, by the detecting antibody S9.6 (red) and DAPI (white) in SMA-like mice (SMA) and littermate controls (Ct) (scale bar = 50 μm). (B) Upper panel: Percentage of S9.6-positive seminiferous tubule of SMA-like mice (SMA, n = 3) and control littermates (Ct, n = 3 mice per genotype). Lower panel: Quantification of tubules containing over five S9.6-positive cells. (C) TUNEL assay of SMA-like mice (SMA) showing a higher amount of positive signal (green). Nuclei were stained with DAPI (white) (scale bar = 50 μm). (D) Percentage of seminiferous tubules with at least one TUNEL-positive cell (upper panel) and average number of TUNEL-positive cells per seminiferous tubule (lower panel). Over 90 tubules/mouse were counted for S9.6 and TUNEL. *Indicates significance, p < 0.05; **, p < 0.005.