The ϵ^ypromoter-neomycinand ϵ^ypromoter-luciferaseconstructs and sense oligomer sequences. (A) Nested deletions of the murine ϵ^y promoter, from 5′ deletions to ATG at +52, were linked to a promoterless neomycin resistance cassette (neo, hatched box), with a wild-type (ϵ^y-CACCCwt, clear oval) or a mutated (ϵ^y-CACCCmut, shaded oval) CACCC-binding site, with or without the murine HS2 (black trapezoid) in Pgem 3zf- (Promega). The transcription start site is at +1. The luciferase reporter constructs contain the minimal functional ϵ^y promoter, at -158, with a wt (clear oval, Pwt) or mutant (mut, shaded oval) CACCC site, linked in frame to a luciferase reporter gene (luc, striped oval) in PGL3 basic (Promega), and with or without HS2 (HS2Pwt and HS2Pmut; black rhomboid) is added to some constructs. (B) Shown is the sequence between -100 and -158 bp that is critical to ϵ^y globin gene promoter function in uninduced MEL cells. The core human fetal γ- and murine adult β-CACCC sites, and murine ϵ^y- and β-CACCC sense oligomers used as gel-shift probes or in in situ mutagenesis are as indicated. Sequences homologous to the ϵ^y promoter are in upper case; 9-bp cores of the CACCC-like sites are underlined; and the ϵ^y-CACCC site mutation is in boldface lower case. The 33-bp CACCC site oligomers are shown, with parentheses indicating the shorter 21-bp and 22-bp probes.