Identification of a novel gene SRG4 expressed at specific stages of mouse spermatogenesis

Spermatogenesis is a complex process. Two spermatocytes expression sequence tags (ESTs) BG101130 and BG100990 were found. Their putative amino acid sequences have high homology with rat Spag4 (sperm antigen 4). By electrical hybridization, a novel cDNA encoding polypeptide of 348 amino acid residues was identified from a mouse testis cDNA library. The new gene was designated as SRG4 (Spermatogenesis related gene 4) (GenBank accession No. AY307077). Results of Northern blot and RTPCR revealed that SRG4 expressed specifically in mouse testis. Changes of SRG4 expression in mouse different development stages were observed by RT-PCR. The SRG4 mRNA was hardly detected in 2 weeks postpartum, and expressed abundantly from 3 weeks later, reaching top lever at 4-5 weeks, while slightly down in aging mouse testis. Results of in situ hybridization showed that SRG4 gene expressed abundantly in spermatocytes, round spermatids. This indicated SRG4 gene may play an important role in mouse meiotic divisions of spermatocytes.