Gli family members are differentially expressed during the mitotic phase of spermatogenesis

The Gli family of DNA binding proteins has been implicated in multiple neoplasias and developmental abnormalities, suggesting a primary involvement in cell development and differentiation. However, to date their specific roles and mechanisms of action remain obscure, and a drawback has been the lack of a model system in which to study their normal function. Here we demonstrate that Gli family members are differentially expressed during spermatogenesis in mice. Specifically, Gli and Gli3 mRNAs were detected in mouse germ cells, while Gli2 was not. Further, both Gli and Gli3 exhibited stage-dependent patterns of expression selectively in type A and B spermatogonia. Gli expression was somewhat higher in type B spermatogonia while the abundance of Gli3 transcripts was similar in type A and B cells. Gel-shift analyses also demonstrated the enrichment of DNA binding activity specific for the Gli target sequence in spermatogonial cells. These results indicate a selective role for Gli and Gli3 during mitotic stages of male germ cell development. Spermatogenesis may thus provide a unique opportunity to identify downstream targets and explore the normal function of Gli family proteins.