FIGURE 4.

Inhibition of CREB1 binding by UNG2 depends upon UNG2 enzymatic activity. Catalytically inactive UNG2 (His-UNG2-D154N) had no effect on total CREB1 binding or dimerization on a CRE site substrate containing a G/U mispair. Wild type or mutant UNG2 was incubated with the substrate prior to the addition of CREB1. □, total bound CREB1 as compared with control; ■, total CREB1 as a dimer as compared with control. i = inactive mutant UNG2, a = active UNG2; numbers in parentheses represent UNG2 concentration. Error bars represent ± S.E., ***, p ≤ 0.001 relative to control.