Figure 3.

Effect of rAP2 on binding of rSp1 and Sp3 binding to an oligonucleotide (EF) containing overlapping CUP/AP2- and Sp-(GT-box) binding sites. EMSA was performed by using ³²P-end-labeled EF oligonucleotide containing the CUP- and Sp-(GT-box) binding sites of the C/EBPα gene promoter (nucleotides −258 to −234). (A) rSp1 was incubated with increasing levels of rAP2. (B) Schneider cell nuclear extract (SL2-NE) containing Sp3 was incubated with increasing levels of rAP2. (C) 3T3-L1 adipocyte nuclear extract (Ad-NE) was incubated in the presence or absence of rAP2. The fast-moving AP-2–oligonucleotide complex is due to a proteolytic product of rAP-2 (7).