Detection of the SRY Transcript and Protein in Bovine Ejaculated Spermatozoa

The sex-determining region on the Y (SRY) gene is important in mammalian sex determination and differentiation. We report a study of the abundance of SRY gene products in bovine ejaculate. RT-PCR experiments using RNA extracted from bovine spermatozoa with SRY-specific primers yielded a 456 bp product, but the amount of SRY mRNA in sperm was lower than that in the testes (p<0.01). A protein of approximately 27 KDa was detected by western blotting. The SRY transcript was detected in the midpiece of approximately half the spermatozoa by in situ hybridization, and the SRY protein was detected in the heads of half the spermatozoa by immunofluorescence, indicating that SRY mRNA and protein may only be present in Y-bearing spermatozoa. These results suggest that the SRY transcript and protein are present in bovine ejaculated Y-sperm. The roles of the SRY gene in spermatogenesis, sperm motility, and the sperm-oocyte interaction merit further investigation. (Key Words : SRY Gene, Bovine Spermatozoa, In situ Hybridization, Bovine)