Characterization and molecular cloning of novel isoforms of human spermatogenesis associated gene SPATA3

This study aimed to clone and characterize novel isoforms of the human SPATA3 gene. The isoforms of SPATA3 gene was cloned into pGMT vector using human testis cDNA as template, and Sanger sequencing was performed. Their characterizations and tissue-specific expression profiles were analyzed. The two novel isoforms were successfully cloned and deposited into GenBank as MG029442 (AYP71042) and MG029443 (AYP71043) respectively. Isoforms SPATA3-I1 and SPATA3-I2 were found with higher identity, where only 7 amino acids missed at N-terminus in SPATA3-I2, whereas SPATA3-I3 and SPATA3-I4 had more C-terminus deletion but in SPATA3-I3 no amino acid missed at N-terminus. Importantly, we found the characterization of QQPSPESTP domain with two repeats for isoforms SPATA3-I1 and SPATA3-I4, whereas three repeats for isoforms SPATA3-I1 and SPATA3-I2. The SPATA3 family of genes is orthologous conserved; the similar core PEST domain was also revealed with variable repeats, indicating that this domain may pay roles in the spermatogenesis and male development differently. Furthermore, RNA-seq data indicated that the SPATA3 gene is only expressed in testis. This further suggests that SPATA3 plays potential roles only in male development, spermatogenesis or spermatogenesis cell apoptosis. Thus, in this study we cloned the two novel isoforms of SPATA3, SPATA3-I3 and SPATA3-I4, and found interesting characteristic PEST domain (QQPSPESTP) conserved in different isoforms as well as in different species. SPATA3 is an essential gene and may functions in male reproductive system, specifically in spermatogenesis.