A novel gene (PD1) with a potential role on rat spermatogenesis

PD1 is a novel protein particularly expressed at the testicular lever. The relative cDNA sequences were cloned from human and rat testis libraries rev ealing an open reading frame for a protein of 520 and 511 amino acids respe ctively. The human PD1 amino acid sequence shows 85% identity with rat sequ ence suggesting that PD1 gene has been highly conserved during mammalian ev olution. Immunohistochemical analysis showed that this protein is detected in the tubular compartment of the testis and, in particular, in the cytopla sm of the Sertoli cells. PD1 expression is not constitutive but seems to be under the influence of neighboring spermatogenic cells as demonstrated by its reduction in hypospermatogenesis with respect to normal spermatogenesis and a further reduction in Sertoli cell-only syndrome. During testicular d evelopment in the rat (from 2 to 45 days of age) the PD1 mRNA level became detectable at 14 days and then increased steadly with an advancement of age . These findings suggest that PD1 may play a role in the regulation of sper matogenesis and may be a potential candidate gene for defects of male ferti lity. (J. Endocrinol. Invest. 23: 605-608, 2000) (C) 2000, Editrice Kurtis.