Induction of epidermal growth factor receptor gene transcription by transforming growth factor beta 1: association with loss of protein binding to a negative regulatory element.
Transforming growth factor beta (TGF-beta) is a potent modulator of cell growth in many systems. In normal rat kidney fibroblasts, TGF-beta 1 increases epidermal growth factor (EGF) receptor gene transcription and synergizes with EGF to stimulate growth in soft agar, a characteristic of the transformed phenotype. In order to identify the target of TGF-beta 1 action, we have used a series of 5' deletion mutants of the EGF receptor promoter linked to a chloramphenicol acetyltransferase reporter gene (ERCAT). The TGF-beta response element(s) was localized to a cis-regulatory region which resides between positions -919 and -860 relative to the ATG translation initiation codon of the EGF receptor promoter. This 60-base pair region contains a repressor of the EGF receptor promoter and a TGF-beta inhibitory element that mediates TGF-beta 1 suppression of transin/stromelysin gene transcription through binding of a Fos-containing protein complex. Cotransfection of c-fos, c-jun, or both expression vectors with the intact or 5'-deleted ERCAT constructs identified several Fos-responsive inhibitory regions within the EGF receptor promoter, but these did not localize to the -919 to -860 promoter region. Mobility shift assays showed binding of the 60-base pair DNA fragment to proteins in extracts from untreated normal rat kidney cells; the binding was specifically competed by oligonucleotides containing a CAGATG sequence but not by oligonucleotides containing the EGF receptor repressor or the TGF-beta inhibitory element. TGF-beta 1 treatment but not anti-Fos antibody caused a decrease in specific 60-base pair DNA-protein complex formation.(ABSTRACT TRUNCATED AT 250 WORDS)
Hou
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Ben May Institute, University of Chicago, IL 60637.
Johnson
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Rosner
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D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D066246:ErbB Receptors / Q000235:genetics*; D005809:Genes, Regulator / Q000187:drug effects*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D016760:Proto-Oncogene Proteins c-fos / Q000502:physiology; D051381:Rats; D014158:Transcription, Genetic / Q000187:drug effects*; D015533:Transcriptional Activation; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D016760:Proto-Oncogene Proteins c-fos; D016212:Transforming Growth Factor beta; D066246:ErbB Receptors