CpG methylation has differential effects on the binding of YY1 and ETS proteins to the bi-directional promoter of the Surf-1 and Surf-2 genes.
The divergently transcribed Surf-1 and Surf-2 housekeeping genes are separated by a bi-directional, TATA-less promoter which lies within a CpG-rich island. Here we show that CpG methylation severely reduces transcription in the direction of both Surf-1 and Surf-2. Previous work has identified three promoter elements (Su1, Su2 and Su3) which are conserved between the human and mouse Surf-1/Surf-2 promoters. These elements bind transcription factors present in human and mouse cell nuclear extracts in vitro and mutations which prevent factor binding also reduce promoter activity in vivo. Transcription initiation factor YY1 binds to the Su1 site and stimulates transcription in the direction of Surf-1 and, to a lesser extent, Surf-2. Here we show that members of the ETS family of transcription factors bind to the Su2 site. Although the Su1 factor binding site contains three CpG dinucleotides, the binding of YY1 is not affected by CpG methylation. In contrast, CpG methylation abolishes the binding of ETS proteins to the Su2 site; methylation of a single cytosine, at position 3 of the consensus ETS site, is sufficient to prevent factor binding. This direct effect on the binding of ETS proteins is, however, not in itself sufficient to explain the repression of this promoter by CpG methylation. A mutation of the Su2 site which removes the sequence CpG, but which does not prevent ETS factor binding, fails to relieve this promoter from repression by CpG methylation.
Gaston
K
K
Department of Biochemistry, School of Medical Sciences, University of Bristol, UK.
Fried
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003596:Cytosine / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015226:Dinucleoside Phosphates / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D017930:Genes, Reporter / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins; D008745:Methylation; D051379:Mice; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D017354:Point Mutation / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011506:Proteins / Q000235:genetics*; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D012097:Repressor Proteins; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D050986:YY1 Transcription Factor
D003596:Cytosine; D004268:DNA-Binding Proteins; D015226:Dinucleoside Phosphates; D050981:Erythroid-Specific DNA-Binding Factors; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D011506:Proteins; D050787:Proto-Oncogene Protein c-ets-2; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D050986:YY1 Transcription Factor; C107465:ERF protein, human; C494069:ETS2 protein, human; C494070:Ets2 protein, mouse; C484292:SURF2 protein, human; C092928:Surf-1 protein; C092929:Surf2 protein, mouse; C494698:YY1 protein, human; C494699:Yy1 protein, mouse; C015772:CpG dinucleotide