Chronological gene expression of ADAMs during testicular development: Prespermatogonia (gonocytes) express fertilin β (ADAM2)

Immediately after birth, primordial germinal cell-derived prespermatogonia (PSG), located in the center of the testicular cords, migrate between adjacent Sertoli cells to establish contact with the cord basal lamina. PSG migration suggests continued assembly and disassembly of cell-cell contacts by a molecular mechanism that may involve integrins and their ligands, the disintegrin domain of spermatogenic cell-specific plasma membrane proteins called ADAMs. We have analyzed the temporal gene expression of selected ADAMs in intact fetal, early postnatal, and pubertal rat testis and Sertoli-spermatogenic cell cocultures by reverse transcriptase-polymerase chain reaction, in situ hybridization, and immunocytochemistry. We report that several ADAM transcripts are expressed in fetal, neonatal, and prepubertal testes. Cyritestin (ADAM3), ADAM5, ADAM6, and ADAM15 are expressed in day 17 fetal testes. In contrast, no expression of fertilin α (ADAM1) and fertilin β (ADAM 2) was detected in fetal testes. Fertilin β gene expression starts after postnatal day 2, subsequent to the expression of fertilin α, which occurs on postnatal day 1. After postnatal day 2, all the indicated ADAMs, including the fertilin α and fertilin β, continue to be expressed. Transcripts of spermatogenic cell-specific fertilin α, β, fertilin β, ADAM3, and ADAM5 were detected during the coculture of PSG with Sertoli cells for up to 72 hr after plating. The presence of fertilin β mRNA and protein in cocultured PSG was visualized by in situ hybridization and immunocytochemistry, respectively. These observations indicate that PSG in coculture with Sertoli cells provide a suitable approach for analyzing cell-cell adhesive responses involving spermatogenic cell-specific ADAMs.