Expression of Notch pathway components in spermatogonia and Sertoli cells of neonatal mice

Members of the Notch gene family have been shown to play an important role in the control of cell fate in many developmental systems. We hypothesized that the fate of the male germ line stem cells may also be mediated through the Notch signaling pathway. We therefore sought to determine whether the components of the Notch pathway are expressed in the mouse testis. Western blot analysis revealed the expression of three Notch receptors (Notch 1, No tch 2, and Notch 3), Notch ligands (Jagged 1, Jagged 2, and Delta 1), and p resenilin 1 (PS1) in neonatal mouse testis. We then examined their cellular localization by immunohistochemical analysis of cocultures of spermatogoni a and Sertoli cells. The 3 Notch receptors were found to be expressed in sp ermatogonia. Sertoli cells expressed only Notch 2 receptor. Among the Notch ligands, Delta 1 and Jagged I were localized exclusively in spermatogonia and Sertoli cells, respectively. PS1 was apparent in both spermatogonia and Sertoli cells. The presence of Notch receptors and Notch ligands in sperma togonia and Sertoli cells indicates that these cells are capable of respond ing to and eliciting Notch signaling during the process of spermatogenesis.