Ontogeny and cellular localization of SRY transcripts in the human testes and its detection in spermatozoa

Abstract

The sex-determining region on the Y (SRY) gene is unequivocally designated as the testis-determining factor in mammals; however, its roles beyond sex determination, if any, have been hitherto unknown. To determine whether SRY has any roles beyond sex determination, herein the expression of SRY mRNA was investigated in the midtrimester human fetal, infantile and adult testes as well as in ejaculated spermatozoa. High levels of SRY transcripts were in situ localized to the Sertoli cells of the developing testis at 9 weeks of gestation, and the expression persisted at comparable levels throughout the midtrimester (until 22 weeks) and also in the testis of an infant at 3 months of age. The germ cells and other somatic cells in the testes of fetuses and the infant were negative for SRY expression. The mRNA for SRY was detected in the spermatogenic cells, particularly the spermatogonia and the round spermatids; the expression was negligible in the meiotic stages. A single transcript of ,1.2 kb was detected in the adult testes and isolated spermatogonial cells. In the adult testis, in situ hybridization (ISH) studies revealed a switch in the cellular localization of SRY transcripts. SRY transcripts were also demonstrable by RT-PCR of RNA from ejaculated human spermatozoa. ISH revealed the presence of SRY transcripts in the midpiece of 50% of ejaculated sperm. These results suggest that SRY may have extensive roles in male reproductive physiology, such as maturation of fetal testis, spermatogenesis, sperm maturation and early embryonic development.

Application of a New Convenience Gender Sorting Method for Mouse Spermatozoa to Mouse Reproductive Engineering Technology

“…The mean female percentage among progenies was 50.3% in the control group, compared with 67.3% in the experimental group. Modi et al (2005) reported that SRY transcription occurs by spermatozoa in humans [10]. From this, we inferred that the same phenomenon may occur in mouse spermatozoa and SRY protein may also occur in spermatozoa.…”

“…When no accidental bias occurs, the gender ratio after ET and Cesarean section is usually 50:50 (female:male). Modi et al (2005) reported that SRY transcription occurs in spermatozoa in humans [10]. From their study, we assumed that the same phenomenon occurs in mouse spermatozoa.…”

“…If this was true, then the sex-determining region Y (SRY) protein may also be produced by spermatozoa. Therefore, we examined the previous report indicating that SRY transcription occurs in spermatozoa in humans [10] and contrived a new technology for gender sorting using fluorescence or magnetic beads via SRY antibody, using mice as an example of mammals.Because the SRY gene consists only of an exon, SRY gene expression was confirmed by two polymerase chain reaction (PCR) experiments using primers designed with a specific sequence of intra-exons to detect cDNA or a sequence ranging from the 5'-genomic region to the exon to detect genomic DNA (Fig. 1).…”

“…If this was true, then the sex-determining region Y (SRY) protein may also be produced by spermatozoa. Therefore, we examined the previous report indicating that SRY transcription occurs in spermatozoa in humans [10] and contrived a new technology for gender sorting using fluorescence or magnetic beads via SRY antibody, using mice as an example of mammals.…”

Identification of a new mouse sperm acrosome-associated protein

“…Sry is a member of the SRY-like box (SOX) gene family of DNA-binding proteins. It has been shown to be expressed in adult testes (Zwingman et al 1994, Modi et al 2005. Similarly, Sox5 expression, New acrosome-associated protein an another member of the SOX gene family, is restricted to postmeiotic germ cells, at its highest level in round spermatids (Denny et al 1992), which makes Sox5 a good candidate for spermatid-expressed gene regulator.…”