PDZ-binding kinase participates in spermatogenesis

A cDNA clone denoted SPK (spermatogenesis-related protein kinase) was isola ted from human fetal brain cDNA library. The deduced protein was 99% identi cal to human PDZ-binding kinase (PBK), which is a mitotic kinase. Its isofo rm, which is about 300 bp longer at 3 ' end, was also isolated in this stud y. SPE: gene was assigned to human chromosome 8p21.2 by radiation hybrid. N orthern blot analysis indicated that SPK mRNA was predominantly expressed i n testis. SPK mRNA was localized to the outer cell layer of seminiferous tu bules by in situ hybridization, suggesting involvement of it in the process of spermatogenesis. (C) 2001 Elsevier Science Ltd. All rights reserved.