Characterization of mouse Tmprss12. (A) Expression of mouse Tmprss12 was examined by RT-PCR using RNA isolated from various organs. Tmprss12 is testis-enriched. The Hprt gene was used as an expression control. He, heart; Li, liver; Sp, spleen; Lu, lung; Ki, kidney; Br, brain; St, stomach; In, intestine; Te, testis; Ov, ovary; Ut, uterus; Ep, epididymis. (B) Expression of mouse Tmprss12 in postnatal days in the testis was examined by RT-PCR. Tmprss12 begins expression at postnatal day 10. The Hprt gene was used as an expression control. (C) Expression of human TMPRSS12 was examined by RT-PCR using RNA isolated from various organs. TMPRSS12 is testis-specific. The GAPDH gene was used as an expression control. H, head (caput); B, body (corpus); T, tail (cauda). (D) Immunofluorescence analysis of spermatozoa from wild-type (WT) mice labeled with antibodies against TMPRSS12 (red) and IZUMO1 (green). Fluorescence was seen in the sperm head and reduced in acrosome-reacted spermatozoa (▲). Nuclei were stained with Hoechst 33342 (blue). Scale bars: 25 μm.