Molecular Cloning of MSRG-11 Gene Related to Apoptosis of Mouse Spermatogenic Cells

A single nucleotide polymorphism in SPATA17 may be a genetic risk factor for Japanese patients with meiotic arrest

Genetic mechanisms have been implicated as a cause of some cases of male infertility. Recently, 10 novel genes involved in human spermatogenesis were identified by microarray analysis of human testicular tissue. One of these is spermatogenesis-associated 17 (SPATA17). To investigate whether defects in the SPATA17 gene are associated with azoospermia due to meiotic arrest, a mutational analysis was conducted, in which the SPATA17 coding regions of 18 Japanese patients with this condition were sequenced. A statistical analysis was carried out that included 18 patients with meiotic arrest, 20 patients with Sertoli-cell-only syndrome (SCOS) and 96 healthy control men. No mutations were found in SPATA17. However, three coding single nucleotide polymorphisms (cSNPs: SNP1-SNP3) were detected in the patients with meiotic arrest. No significant differences in the genotype or allele frequencies of SNP1 and SNP2 were found between patients with meiotic arrest and the others. However, the frequency of the SNP3 allele was significantly elevated in the meiotic arrest group (P < 0.05). This study suggests that SPATA17 may play a critical role in human spermatogenesis, especially in meiosis.

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.