title: Roles of promoter and 3' untranslated motifs in expression of the human C5a receptor.
abstract: The C5a receptor (C5aR) is a 7 transmembrane G-protein coupled receptor (GPCR) that mediates the powerful pro-inflammatory effect of the complement activation product C5a. Excess C5a generated under pathological conditions has been implicated in a variety of conditions including sepsis, asthma and rheumatoid arthritis, but very little is known about the regulation of expression of the C5aR. The 5' promoter region and 3' untranslated region (UTR) of the C5aR mRNA were cloned, generating enhanced green fluorescent protein (EGFP)-reporter plasmids, which were transfected into the monocytic cell line U937. Most of the cloned 2kb 5' region was dispensable for the expression of the reporter constructs and the majority of regulatory sequences are in the first 200 bp. Three motifs, a NFκB, a CCAAT and a NFAT site, were identified to be of importance by site directed mutagenesis for basal expression. Analysis of the 3'UTR of the C5aR mRNA showed that it contained two AU-rich elements (AREs), however site directed mutagenesis showed that these had no effect on basal expression. While the phorbol ester PMA and dibutyryl cAMP increased C5aR protein expression, these agents had no effect on the regulation of expression via the promoter or the 3'UTR. This is the first study to investigate the role of both the promoter and 3'UTR in regulating C5aR expression and our results show that regulation of the human C5aR is similar but not identical to that of the mouse C5aR.
authors.affiliation: Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Palmer
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Gray
authors.forename: Matthew
authors.initials: M
authors.lastname: Stott
authors.forename: Derrick J
authors.initials: DJ
authors.lastname: Bowen
authors.forename: Carmen W
authors.initials: CW
authors.lastname: van den Berg
mesh_terms: D020413:3' Untranslated Regions; D020816:Amino Acid Motifs; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D003994:Bucladesine / Q000494:pharmacology; D023081:CCAAT-Binding Factor / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D003001:Cloning, Molecular; D018387:Codon, Initiator / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D051379:Mice; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism; D011401:Promoter Regions, Genetic; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D020298:U937 Cells
chemical_list: D020413:3' Untranslated Regions; C488033:C5AR1 protein, human; D023081:CCAAT-Binding Factor; D018387:Codon, Initiator; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D011994:Recombinant Proteins; D003994:Bucladesine; D013755:Tetradecanoylphorbol Acetate