Structural and functional characterization of the mouse c-met proto-oncogene (hepatocyte growth factor receptor) promoter.
The c-met gene encoding Hepatocyte Growth Factor Receptor is predominantly expressed in epithelial cell types and overexpressed in a variety of human and mouse neoplastic tissues and cell lines. To understand the molecular mechanisms of the transcriptional regulation of this gene, we have cloned and functionally characterized the mouse c-met promoter region. Transient transfection analysis using a series of 5'-end deletion met-CAT chimeric constructs in epithelial (C-33A) and fibroblast (NIH3T3) cell lines demonstrated that the c-met promoter acts in a cell-type specific manner. These experiments also localized functionally important regulatory regions at -1390 to -279, relative to the transcription start site, which exert repressive activity, and at -278 to -77 which exhibit enhancing effects on c-met promoter activity. Further analysis by electrophoretic mobility shift assays using specific competitors and antibodies identified Sp1 protein binding to two cognate response elements at -221 and -124 within the enhancer region. Cotransfection experiments revealed that Sp1 stimulated promoter activity of the met-CAT constructs containing the two Sp1 binding sites. These results demonstrate that Sp1 is actively involved in the transcriptional regulation of the c-met promoter.
Seol
D W
DW
Department of Pathology, University of Pittsburgh School of Medicine, PA 15261, USA.
Zarnegar
R
R
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D000090063:Proto-Oncogene Mas; D019859:Proto-Oncogene Proteins c-met / Q000096:biosynthesis / Q000235:genetics*; D011519:Proto-Oncogenes; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D014162:Transfection
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011993:Recombinant Fusion Proteins; D015500:Chloramphenicol O-Acetyltransferase; D019859:Proto-Oncogene Proteins c-met