The CDP-ɛ–binding site is distinct from the CDP- binding site. (A) Schematic illustration of the positions of gp91^phox promoter regions used in EMSA in comparison to the CDP- site. CDP-, −136 to −76 bp; CDP-ɛ, −102 to −65 bp; 5′CDP-, −136 to −102 bp; MIN, −121 to −94 bp; 5′CDP-ɛ, −100 to −81; 3′CDP-ɛ, −93 to −65 bp. (B) EMSA showing that the binding of CDP to the CDP-ɛ site is distinct from CDP binding to the CDP- site. EMSA was performed as described in Materials and Methods, with nuclear extract isolated from HeLa cells. Antiserum directed against CDP was added to the indicated samples. EMSA was performed by using the MIN oligonucleotide as a probe and nuclear extract derived from HeLa cells. Five or 10 ng of CDP-ɛ (or equimolar amounts of the other oligonucleotides) were added as competitors where indicated. The Spi-B oligonucleotide is included as a heterologous competitor.