STAGE-SPECIFIC EXPRESSION OF TESTIS-SPECIFIC PROTEIN-KINASE-1 (TESK1)IN RAT SPERMATOGENIC CELLS

TESK1 (testis-specific protein kinase 1) is a serine/threonine kinase, with a unique structure composed of an N-terminal protein kinase doma in and a C-terminal proline-rich domain. Northern blot analysis reveal ed that TESK1 mRNA is predominantly expressed in testicular germ cells . We present here evidence that expression of TESK1 mRNA and protein i n the rat testes is developmentally regulated and increases after 20-2 2 postnatal days. To identify cells which express TESK1 mRNA and prote in during male germ cell differentiation, in situ hybridization and im munohistochemistry were done using frozen sections of adult rat testes . Prominent expression of TESK1 mRNA and protein was detected in testi cular germ cells at stages of late pachytene spermatocytes to round sp ermatids, but not in somatic cells such as Sertoli and Leydig cells. E xpression of TESK1 mRNA and protein at specific stages of testicular g erm cells suggests a role for this kinase in spermatogenesis, particul arly at stages of meiosis and/or early spermiogenesis. (C) 1998 Academ ic Press.