Expression and identification of a novel apoptosis gene Spata17 (MSRG-11) in mouse spermatogenic cells

In this study, anti-spermatogenesis-associated 17 (Spata17) polyclonal antibody was prepared by immunizing New Zealand white rabbits with a synthesized peptide corresponding to the amino acid sequence 7-23 of the mouse Spata17 protein. Immunohistochemical analysis revealed that Spata17 protein was most abundant in the cytoplasm of round spermatids and elongating spermatids within seminiferous tubules of the adult testis. The expression of Spata17 mRNA in cultured mouse spermatogonia (GC-1) cells was almost undetectable. In an experimental unilateral cryptorchidism model of an adult mouse, the expression of Spata17 mRNA had no obvious difference with the normal testis until postoperation day 1, but gradually decreased from day 3 and was almost undetectable on day 17. Immunohistochemical analysis revealed that the protein was almost undetectable within seminiferous tubules of an experimental unilateral cryptorchidism model of the adult testis on postoperation day 8. Flow cytometry analysis showed that the expression of Spata17 protein in the GC-1 cell line could accelerate GC-1 cell apoptosis. The effect increases with the increasing of the transfected dose of pcDNA3.1(-)/Spata17. By Hoechst 33258 staining, a classical way of identifying apoptotic cells, we further confirmed that the apoptosis was induced by expression of Spata17 in transfected GC-1 cells.