MOLECULAR-STRUCTURE OF THE MOUSE CCK-A RECEPTOR GENE

We have cloned the mouse CCK-A receptor gene (Cckar), determined its n ucleotide sequence, and analyzed its expression. The receptor protein is encoded in five exons distributed over 9 kb of genomic DNA. Intron/ exon borders were determined by comparing the genomic nucleotide seque nce with the mouse cDNA sequence obtained by reverse transcriptase pol ymerase chain reaction. RNase protection analysis of Cckar transcripts revealed the presence of a splice acceptor site 200 bp upstream of th e translational start codon, indicating that the promoter is associate d with a non-translated exon at an upstream site. The second coding ex on contains a rarely used alternative splice site that would result in the production of a truncated, 48 amino acid protein. Cckar is widely expressed in the gastrointestinal system (pancreas, gallbladder, inte stine, colon and stomach), as well as in brain and kidney. (C) 1997 Ac ademic Press.