Identification of variants and dual promoters of murine serine/threonine kinase KKIAMRE

Abstract

KKIAMRE is a serine/threonine protein kinase whose transcripts increase in the deep cerebellar nuclei of the rabbit after eyeblink conditioning, a model of associative learning and memory. We here characterized the expression, isoforms, and promoters of murine KKIAMRE gene. The expression of KKIAMRE was detected, by in situ hybridization and immunohistochemistry, in neurons in various brain regions including deep cerebellar nuclei. The gene spans approximately 40 kb and consists of 15 exons. Analysis of cDNA clones revealed multiple variants, having diversity in the putative carboxy-terminal regulatory domain, generated by alternative splicing and intraexonal termination. Furthermore, they had alternative 5' noncoding sequences. Primer extension, RNase protection, and transient expression assays revealed that two alternative promoters linked to distinct noncoding exons direct the expression of KKIAMRE. The gene was mapped on chromosomes 5 and 4 in mouse and human, respectively.