title: Structure and transcription of the human m3 muscarinic receptor gene.
abstract: We have isolated and characterized the human m3 muscarinic receptor gene and its promoter. Using 5' rapid amplification of cDNA ends (RACE), internal polymerase chain reaction (PCR), and homology searching to identify EST clones, we determined that the cDNA encoding the m3 receptor comprises 4,559 bp in 8 exons, which are alternatively spliced to exclude exons 2, 4, 6, and/or 7; the receptor coding sequence occurs within exon 8. Analysis of P1 artificial chromosome (PAC) and bacterial artificial chromosome (BAC) clones and of PCR- amplified genomic DNA, and homology searching of human chromosome 1 sequence provided from the Sanger Centre (Hinxton, Cambridge, UK) revealed that the m3 muscarinic receptor gene spans at least 285 kb. A promoter fragment containing bp -1240 to +101 (relative to the most 5' transcription start site) exhibited considerable transcriptional activity during transient transfection in cultured subconfluent, serum-fed canine tracheal myocytes, and 5' deletion analysis of promoter function revealed the presence of positive transcriptional regulatory elements between bp -526 and -269. Sequence analysis disclosed three potential AP-2 binding sites in this region; five more AP-2 consensus binding motifs occur between bp -269 and +101. Cotransfection with a plasmid expressing human AP-2alpha substantially increased transcription from m3 receptor promoter constructs containing 526 or 269 bp of 5' flanking DNA. Furthermore, m3 receptor promoter activity was enhanced by long-term serum deprivation of canine tracheal myocytes, a treatment that is known to increase AP-2 transcription-promoting activity in these cells. Together, these data suggest that expression of the human m3 muscarinic receptor gene is regulated in part by AP-2 in airway smooth muscle.
authors.affiliation: Section of Pulmonary and Critical Care Medicine, Department of Medicine, Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Sean M
authors.initials: SM
authors.lastname: Forsythe
authors.forename: Paul C
authors.initials: PC
authors.lastname: Kogut
authors.forename: John F
authors.initials: JF
authors.lastname: McConville
authors.forename: Yiping
authors.initials: Y
authors.lastname: Fu
authors.forename: Joel A
authors.initials: JA
authors.lastname: McCauley
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Halayko
authors.forename: Hong Wei
authors.initials: HW
authors.lastname: Liu
authors.forename: Allen
authors.initials: A
authors.lastname: Kao
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Fernandes
authors.forename: Shashi
authors.initials: S
authors.lastname: Bellam
authors.forename: Elaine
authors.initials: E
authors.lastname: Fuchs
authors.forename: Satrajit
authors.initials: S
authors.lastname: Sinha
authors.forename: Graeme I
authors.initials: GI
authors.lastname: Bell
authors.forename: Blanca
authors.initials: B
authors.lastname: Camoretti-Mercado
authors.forename: Julian
authors.initials: J
authors.lastname: Solway
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D004285:Dogs; D005091:Exons / Q000235:genetics; D015894:Genome, Human; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D018076:DNA, Complementary; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic