The carboxyl-terminal anchorage domain of the turkey beta 1-adrenergic receptor is encoded by an alternatively spliced exon.
The originally described cDNA of the turkey beta 1-adrenergic receptor encodes a receptor with a carboxyl-terminal, 59-amino acid extension that was not found in several mammalian beta 1-adrenergic receptors. This extension blocks agonist-promoted endocytosis and down-regulation of the receptor. This carboxyl-terminal domain is encoded by an exon distinct from that which encodes the body of the receptor, and the originally described cDNA results from removal of an 849-nucleotide intron. Unspliced mRNA encodes a shorter open reading frame whose translated carboxyl terminus is identical with that of the mammalian beta 1-adrenergic receptors. There is no evidence for other introns in the coding region. Splicing of the intron to produce the non-endocytosing receptor is highest in fetal blood cells, is appreciable in adult brain and heart, and is detectable in other tissues. Thus, different tissues use alternative splicing to express beta-adrenergic receptors that either do or do not endocytose and down-regulate in response to agonist.
Wang
J
J
Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235-9041.
Ross
E M
EM
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005091:Exons; D007438:Introns; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics*; D016133:Polymerase Chain Reaction; D051381:Rats; D018342:Receptors, Adrenergic, beta-1 / Q000235:genetics*; D014422:Turkeys
D010446:Peptide Fragments; D018342:Receptors, Adrenergic, beta-1