Interaction of Ets-1 and Sp1 with −80/−33 region of the PDGF-Rα promoter requires −45TTCC−42 and −61G10−52. Oligonucleotides spanning the −80/−33 region of the PDGF-Rα proximal promoter were incubated with indicated recombinant (r) protein. EMSA using rEts-1 (A), rSp1 (B), or rEts-1 and rSp1 (C). The arrow indicates the nucleoprotein complex. Wild-type 32P-Oligo −80/−33, or 32P-Oligo −80/−33mEts (where −45TTCC−42 was changed to −45TACA−42), an Sp1 mutant, 32P-Oligo −80/−33mSp1 (where −61G10−52 was changed to −61T10−52) and a double mutant, 32P-Oligo −80/−33mSp1mEts (where both sites were mutated). D: Chromatin immunoprecipitation analysis demonstrating amplification of the PDGF-Rα promoter in the total input, without antibody pull-down (no Ab), or pulled down with Sp1 and Ets-1 antibodies. The data are representative of at least two independent determinations.