Nephrin is an important component of the barrier system in the testis

Nephrin, a gene product of the congenital nephrotic syndrome of the Finnish type (NPHS1), is a 1242-residue putative transmembrane protein of the immu noglobulin family of cell adhesion molecules. The expression of this gene i s localized in rat and human glomerular epithelial cells. Here we report th e expression of nephrin in various tissues other than the kidneys in mice. The expression of nephrin mRNA in various tissues of mice, including the ki dneys, testes, spleen, thymus and brain, were first investigated by the RT- PCR method, and it was shown that a high level of nephrin mRNA could be det ected in the testes of mice 1-6 weeks old. In situ hybridization revealed t he expression of the nephrin gene in the Sertoli cells. Additionally, immun ofluorescent staining studies indicated that nephrin was colocalized with a nchoring protein ZO-1 in the mouse testis, From these results, it is inferr ed that nephrin is an important component of the barrier system in testes.