title: Characterization of the PLCB1 promoter and regulation by early growth response transcription factor EGR-1.
abstract: The Gαq/-Gα11-PLCβ1 pathway is important for intracellular signalling and associated with pathological conditions, such as cardiac hypertrophy. The GNAQ and GNA11 promoters (encoding for Gαq and Gα11) have already been characterized and are both regulated by the transcription factor early growth response 1 (Egr-1). In contrast, the PLCB1 promoter (encoding for the direct downstream effector PLCβ1) has neither been cloned nor characterized. Therefore, the purpose of this study was to 1) characterize the PLCB1 promoter, and 2) assess its potential regulation by Egr-1. By means of 5'- Rapid Amplification of 5'-cDNA ends analysis in human heart tissue we found an initiation of transcription from multiple starting points, the main transcription starting point being located at nt-235 relative to the translation start point. The PLCB1 promoter was cloned and deletion constructs were generated. Luciferase assays were performed in three different cell lines and regulatory regions were identified between nt-595/nt-313 (Hek293: P=0.013; HASMC: P=0.019; H9c2: P=0.005). In electrophoretic mobility shift assays one specific Egr-1 binding site was identified at nt-451/-419 and PLCB1 promoter activity was increased more than 5-fold (Hek293: P=0.0008) and 1,6- fold (H9c2: P=0.0499) following overexpression of Egr-1. Thus, the PLCB1 promoter was characterized for the first time and a specific interaction with the transcription factor Egr-1 was shown. Our data provide a potential molecular mechanism relating to pathophysiological conditions such as cardiac hypertrophy where activation by Egr-1 of Gαq/Gα11-PLCβ1 plays an important role.
authors.affiliation: Institut für Pharmakogenetik, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany; Klinik für Anästhesiologie & Intensivmedizin, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany. Electronic address: Stefanie.Klenke@uk-essen.de.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Klenke
authors.affiliation: Institut für Pharmakogenetik, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany; Klinik für Anästhesiologie & Intensivmedizin, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Rump
authors.affiliation: Klinik für Anästhesiologie & Intensivmedizin, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Buschkamp
authors.affiliation: Klinik für Anästhesiologie & Intensivmedizin, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Engler
authors.affiliation: Klinik für Anästhesiologie & Intensivmedizin, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Peters
authors.affiliation: Institut für Pharmakogenetik, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany.
authors.forename: Winfried
authors.initials: W
authors.lastname: Siffert
authors.affiliation: Klinik für Anästhesiologie & Intensivmedizin, Universität Duisburg-Essen and Universitätsklinikum Essen, Hufelandstr. 55, D-45122 Essen, Germany.
authors.forename: Ulrich H
authors.initials: UH
authors.lastname: Frey
mesh_terms: D024506:5' Flanking Region; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D051766:Early Growth Response Protein 1 / Q000378:metabolism*; D005786:Gene Expression Regulation; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D032383:Myocytes, Cardiac / Q000378:metabolism; D054799:Phospholipase C beta / Q000235:genetics*; D011401:Promoter Regions, Genetic; D051381:Rats
chemical_list: C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; C518033:PLCB1 protein, human; D054799:Phospholipase C beta
keywords: Egr-1; Gene expression; Gene regulation; Hypertension; PLCB1; Promoter