Molecular and Functional Characterization of Human Sex-Determining Region on the Y Chromosome Variants Using Protamine 1 Promoter.

The male sex-determining gene, sex-determining region on the Y chromosome (), is expressed in adult testicular germ cells; however, its role in regulating spermatogenesis remains unclear. The role of in the postmeiotic gene expression was investigated by determining the effect of on the promoter of the haploid-specific Protamine 1 () gene, which harbors five distinct -binding motifs. In a luciferase reporter assay system, upregulates promoter activity in a dose-dependent manner. Through a gel-shift assay involving a 31-bp DNA fragment encompassing the element within the promoter, the third -binding site on the sense strand (-373/-367) was identified as crucial for promoter activation. This assay was extended to analyze 9 variants found in the testicular DNA of 44 azoospermia patients. The findings suggest that regulates promoter activity by directly binding to its specific motif within the promoter.