The spermatogenesis associated protein 4 (SPATA4) protein, also known as TSARG1, is highly expressed in testis, and to a much lower extent in other tissues. SPATA4 contains a highly conserved DUF1042 domain, but no significant homology with any other known protein. SPATA4 is thought to play an important role in the development of cryptorchid testis and is a testis-specific apoptosis candidate oncogene.Synonyms: SPEF1B, Spermatogenesis-associated protein 4, Testis and spermatogenesis cell-related protein 2, Testis spermatocyte apoptosis-related gene 2 protein