Initial characterization of a potential transcriptional enhancer for the human c-K-ras gene.
The nucleotide sequence of the 5' end distal region of the human c-K-ras gene promoter was determined. This region, coincident with a variable DNAse I hypersensitive site in native chromatin, contains sequence similarities with known enhancers. A 400 bp MstII DNA fragment of this region stimulated in cis the correctly initiated transcription of the human beta-globin gene in transfected Hela cells. The stimulation of beta-globin transcription (5-6 fold) was dependent on the distance and orientation of the c-K-ras sequences and on the presence of the CCAAT and CACCC elements in the beta-globin promoter. Interaction of nuclear factors with these c-K-ras sequences was analysed by DNAase I footprinting assays using Hela nuclear extracts. A protein binding to these sequences was identified as nuclear factor 1 (NF-1) by DNAase I competition footprinting experiments. However, disruption of the c-K-ras NF-1 binding site by insertion mutagenesis had no effect on the transcriptional activity of the c-K-ras element.
Jordano
J
J
Department of Biochemistry, State University of New York, Stony Brook 11794.
Perucho
M
M
D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D005914:Globins / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014157:Transcription Factors; D014158:Transcription, Genetic; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D005914:Globins; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)