DNA-binding proteins that interact with the proximal gp91^phox promoter. The transcriptional repressor CDP competes with the binding of transcriptional activation factors at 6 sites (δ, γ, β, , and ɛ- and ζ-, the proposed fifth and sixth binding sites). The DNA binding activity of CDP is down-regulated during terminal phagocyte development, allowing the transcriptional activators to interact with the gp91^phoxpromoter.5,8,9 13 Plus (+)1 indicates the site of transcription initiation. Lines above δ, γ, β, , ɛ, and ζ indicate the positions of each of 5 oligonucleotides used as CDP-binding sites.