Cloning, expression analysis and chromosome mapping of human casein kinase1 gamma 1 (CSNK1G1): Identification of two types of cDNA encoding the kinase protein associated with heterologous carboxy-terminal sequences

Casein kinase 1 gamma1 (CK1 gamma1) is known to be involved in the growth a nd morphogenesis of eukaryotic cells. We have isolated two types of cDNA fo r human casein kinase 1 gamma1 (hCK1 gamma1). One of them (hCK1 gamma 1S) w as found to encode a polypeptide consisting of 393 amino acids, which is hi ghly homologous with already reported rat CK1 gamma1 (rCK1 gamma1). The oth er type of cDNA (hCK1 gamma 1L) encodes a polypeptide consisting of 422 ami no acids, which is quite identical in the kinase domain, but different in t he C-terminal sequence from hCK1 gamma 1S. Namely, hCK1 gamma 1L has a char acteristic sequence of 50 amino acids at the C-terminal end and this motif was shown to be shared by the casein kinase gamma2 and gamma3 from rat and human, suggesting that it is a signature sequence of the gamma -isoforms. I n this sense, newly isolated hCK1 gamma 1L might be the original form of CK 1 gamma1 subspecies rather than rCK1 gamma1 and hCK1 gamma 1S. RT-PCR analy sis revealed that hCK1 gamma 1S mRNA is predominantly present in the testis , whereas the abundance of hCK1 gamma1 mRNA was nearly the same in the twel ve tissues examined. These results suggest that novel hCK1 gamma 1L may hav e a unique functional role different from that of hCK1 gamma 1S and rCK1 ga mma1. The human hCK1 gamma1 gene (CSNK1G1) was mapped to chromosome 15q22.1 -->q22.31 by fluorescence in situ hybridization. Copyright (C) 2000 S. Karg er AG, Basel.