Small introns in a hepatic cDNA encoding a new glucagon-like peptide 1-type receptor

A cDNA fragment was PCR amplified at low-stringency from rat DNA, using two degenerated primers corresponding to consensus sequences in the second and third transmembrane segments of members of the secretin receptor family. A synthetic oligodeoxynucleotide based on the 3 end of this fragment, when used in Northern-blot analysis, hybridized to a broad 1.5-3.0 kb band in rat liver. It was then used as a probe for screening a cDNA library generated from size-fractionated rat liver poly(A)+ RNA. Overlapping alignment of sequences from 3 clones identified a 1455 residue open reading frame encoding a 485 amino acid peptide showing 7 putative transmembrane segments and 42% identity with the glucagon-like peptide 1 (GLP-1) receptor. In addition, four small (85-300 bp) introns were variously represented in the isolated clones.