A novel mammalian kinase, T/STK 30, is highly expressed in the germ line

In order to identify potential regulators of germ cell development in mammals we isolated serine/threonine kinases from adult testis because kinases have been found to play important roles in regulating both mitotic and meiotic cell cycles in a variety of organisms. One of the isolated genes, termed testis‐derived serine/threonine kinase 30 (T/STK 30) revealed homology to the rat male germ cell associated kinase (Mak) and to a key regulator of entry into meiosis, the SME1 kinase from Saccharomyces cerevisiae (S. cerevisiae). T/STK 30 is most abundantly expressed in the testis and ovary and at low levels in the brain, but not in other adult tissues, during embryogenesis or in proliferating somatic cells. T/STK 30 transcripts were not detected in RNA from a sterile Steel (Sl) mutant testis, further demonstrating that T/STK 30 expression in the testis is limited to germ cells. Analysis of T/STK 30 expression in the developing testis revealed that T/STK 30 transcripts are detected in RNA from testis 17 days postpartum, but not 7 days postpartum, suggesting that T/STK30 expression is restricted to meiotic and postmeiotic germ cells. In situ hybridization analysis of T/STK 30 expression in the testis and ovary confirmed that this gene is highly expressed in germ cells. Thus T/STK 30 may be an important regulator of meiosis or postmeiotic differentiation in mammals. Mol. Reprod. Dev. 52:9–17, 1999. © 1999 Wiley‐Liss, Inc.