title: Thyroid hormone influences beta myosin heavy chain (beta MHC) expression.
abstract: 3,5,3'-Triiodo-L-thyronine (T3) regulation of beta-MHC expression was studied in rat fetal heart cells using deletion mutants of both the rat and human promoter regions fused to a CAT expression vector. T3 inhibited the expression of human and rat beta-MHC constructs with an IC50 of about 1nM, which was similar to the EC50 for beta MHC-mRNA observed in cardiomyocytes. Deletion analysis of beta MHC promoter constructs suggested that a T3 response element (TRE) is located near the start of transcription. Possibly, T3-receptor binding at this site interferes with formation of the transcriptional initiation complex.
authors.affiliation: University Heart Center, University of Arizona, Tucson 85724.
authors.forename: J G
authors.initials: JG
authors.lastname: Edwards
authors.forename: J J
authors.initials: JJ
authors.lastname: Bahl
authors.forename: I L
authors.initials: IL
authors.lastname: Flink
authors.forename: S Y
authors.initials: SY
authors.lastname: Cheng
authors.forename: E
authors.initials: E
authors.lastname: Morkin
mesh_terms: D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005333:Fetus; D015870:Gene Expression / Q000187:drug effects*; D005865:Gestational Age; D006321:Heart / Q000187:drug effects*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009206:Myocardium / Q000378:metabolism*; D009218:Myosins / Q000096:biosynthesis* / Q000235:genetics*; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D017384:Sequence Deletion; D014162:Transfection; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D011994:Recombinant Proteins; D014284:Triiodothyronine; D015500:Chloramphenicol O-Acetyltransferase; D009218:Myosins