Cloning and chromosomal mapping of human casein kinase I gamma 2 (CSNK1G2)

A clone of immature cDNA for human casein kinase I gamma 2 (CSNK1G2) was isolated by screening the human testis cDNA library with a PCR-amplified probe (about 400 bp) representing the kinase domain of rat casein kinase I gamma 2 (CKI gamma 2). Comparison of the entire sequence with that of rat CKI gamma 2 showed that the cDNA contained the complete coding sequence of CKI gamma 2 as well as an intron-like sequence of 1006 bp, part of which was homologous to the Alu sequence. To obtain an insertion-free CSNK1G2 cDNA, PCR cloning was performed based on the above sequence. The amplified 1687-bp fragment was subcloned and sequenced. The predicted amino acid sequence consisted of 416 residues, 94% of which were identical to that of the rat homologue. Although there are two Src homology 3 (SH3) domain-binding motifs (Pro-X-X-Pro consensus), Pro-Lys-Val-Pro and Pro-Ser-Glu-Pro in the C-terminal region of rat CKI gamma 2, only the latter was conserved in the human counterpart. This finding suggests that the latter motif is important for binding to the signal transduction adaptor protein Nck (NCK). The human CSNK1G2 gene was mapped to chromosome 19p13.3 by fluorescence in situ hybridization and PCR analysis of the human/rodent hybrid cell panel.