PACAP is a peptide in the VIP/secretin/glucagon neuropeptide family which elicits an impressive array of biological effects via interactions with Type I (PACAP-selective) and Type II (non-selective between PACAP and VIP) PACAP receptors (PACAPR). Using long distance polymerase chain reaction (PCR), we amplified and characterized the entire coding region of the rat Type I PACAPR gene which spans 40 kb and contains 15 exons. Mapping of the exons and sequencing or all intron-exon boundaries revealed a structural organization of the PACAPR gene that is very similar to those encoding other members in the calcitonin/secretin/PTH family of G protein-coupled receptors. Splice acceptor sites used to generate the hip and hop cassette forms of the PACAPR were mapped to exon 12 at locations 2.8 and 7.7 kb from its 5′ end, respectively. Southern blot analysis demonstrated a single copy of the PACAPR gene in the rat genome. Anchored PCR was used to amplify up to 5 kb of genomic sequence upstream of the ATG start codon. A combination of rapid amplification of cDNA ends and reverse transcriptase PCR revealed an unexpected diversity in the PACAPR mRNA in the 5′-untranslated region (5′-UTR). Four PACAPR cDNAs were identified with 5′-UTRs that all diverged from the genomic sequence at a site 76 bp upstream of the ATG start codon, where a consensus 3 slice acceptor sequence was located. Analysis of the sequence of these four cDNAs suggests that their diversity can be explained by alternative splicing of three non-coding exons in the 5′-UTR. These results are the first to demonstrate the structural organization of the PACAPR gene and to reveal the existence of alternative splicing in its 5′-UTR (NIH HL41071, DK25295).
|Original language||English (US)|
|Publication status||Published - Dec 1 1996|
ASJC Scopus subject areas
- Molecular Biology