Genomic cloning, structure, and regulatory elements of the 1 alpha,25(OH)(2)D-3 down-regulated gene for cyclic AMP-dependent protein kinase inhibitor

The cyclic AMP-dependent protein kinase inhibitor (PKI) mRNA and protein ar e negatively and tissue-specifically regulated in the kidney by 1 alpha,25( OH)(2)D-3. A 17-kb PKI clone, isolated from a chick genomic library, reveal ed that the PKI gene consists of two exons separated by a 4.5-kb intron. A 411-bp upstream region (constituting 93 bp upstream and 318 bp downstream f rom the transcriptional start site) containing a putative negative VDRE (nV DRE) fused to the luciferase gene was used for transient transfections of p rimary cultures of chick kidney cells. Luciferase activity was significantl y downregulated in response to 1 alpha,25(OH)(2)D-3. This result suggests t hat the promoter region containing the putative nVDRE plays a pivotal role in the negative regulation of PKI gene transcription. (C) 1999 Elsevier Sci ence B.V. All rights reserved.