STRUCTURAL FEATURES OF THE MURINE GENE ENCODING THE RI-BETA SUBUNIT OF CAMP-DEPENDENT PROTEIN-KINASE

The activation of cyclic AMP-dependent protein kinase is controlled by the regulatory (R) subunits of the holoenzyme. Here we present a char acterization of the mouse RI beta subunit gene, which in contrast to o ther subunit genes of cyclic AMP-dependent protein kinase is expressed almost exclusively in neurons. It was determined that RI beta is rela tively large with 11 exons spanning a minimum 75 kb. The mouse chromos omal locus (designated Prkar1b) was determined by interspecific backcr oss mapping and found to reside on the distal arm of chromosome 5. Pre viously, it was shown that 3.5 kb of DNA encompassing the RI beta prom oter could direct neural-specific gene expression in transgenic mice. Analysis of this DNA suggests the presence of an unusually large numbe r of binding sites for transcription factors ranging from tissue-speci fic regulators, immediate-early genes, and mediators of hormone action . In addition to 18 putative SP1 sites, we identified 27 consensus seq uences for basic Helix-Loop-Helix, POU, and Pax family members, 5 AP1 sites, and over 40 half-sites for the superfamily of steroid hormone r eceptor. Gel mobility-shift assays employing brain nuclear extract and pure transcription factor protein established that many of these DNA sequences are functional in binding protein. The abundance and configu ration of transcription factor binding sites within the promoter regio n of RI beta suggests that this gene is subject to complex modes of re gulation in neurons. (C) 1994 Academic Press, Inc.