MOLECULAR CHARACTERIZATION OF THE HUMAN PROTEIN-KINASE-C 0-ASTERISK GENE LOCUS (PRKCQ)

Members of the protein kinase C (PKC) family of serine/threonine kinas es, in particular PKC theta, play critical roles in the regulation of differentiation and proliferation of T lymphocytes. In this study the genomic structure of the human PRKCQ gene that encodes PKC theta was d etermined. Two genomic PI clones were isolated from human P1 libraries using the PKC theta cDNA as a probe and have been used to confirm the assignment of the single PRKCQ locus to chromosome 10p15 by FISH anal ysis. The PRKCQ locus, the first mammalian PKC gene locus characterize d so far, spans approximately 62 kb and is composed of 15 coding exons and 14 introns, varying in size between 98 and 16000 bp. All exon-int ron boundaries have been determined by long-range PCR and subsequent D NA sequence analysis. Comparison with other known genomic PKC genes re veals a high degree of homology to the genomic organization of the Dro sophila melanogaster dPRKC gene. Alignment of the intron positions in the PRKCQ gene with the intron locations in the dPRKC gene indicates t hat the sites of seven of the 14 PRKCQ introns are exactly conserved. Exons 5 (32 bp), 11 (174 bp) and 12 (92 bp) share highest similarity i n size, organization and primary structure with their counterparts in the Drosophila gene. On the basis of this knowledge of the genomic PRK CQ locus, a directed search for potential genetic polymorphisms and/or genetic abnormalities involved in human genetic disease(s) can now be initiated.