An Rb1-E2F1 complex binds the
promoter and constitutively represses the gene. (A) Alignment of both human and mouse Ets1 promoter sequences showing two regions of higher similarity that contains consensus E2F binding sites (boxed). (B) A schematic diagram of mouse Ets1 promoter with two putative E2F sites. SST: start site of transcription. (C) Chromatin immunoprecipitation (ChIP) assay demonstrates binding of Rb1 and E2F1 to the Ets1 promoter together with the positive control histone H3. Input indicates the DNA used for immunoprecipitation, IgG is control serum and mock indicates no added DNA. (D) Electrophoretic mobility shift assay (EMSA) demonstrates reduction of the specific binding of the crude protein lysate to the target DNA oligo upon mutation of its putative E2F site. ‘wt’ denotes a wild-type oligo with a putative E2F site while ‘mt’ indicates a mutant oligo with a mutated E2F site.