Figure 7.

RNA and DNA compete for binding to TDG. A, preformed complexes between DNA_FU (100 nM) and TDG (200 nM) are disrupted by G₃₀ RNA (left) but not A₃₀ RNA (right). The “DNA” marker indicates DNA_FU in the absence of TDG and RNA. The percent free (unbound) DNA_FU is indicated underneath each lane. B and C, TDG-mediated excision of DNA_U (B) and DNA_T (C) is inhibited by RNA. For each reaction, the DNA substrate (100 nM) was mixed with the indicated concentration of G₃₀ RNA or 5 μM A₃₀ RNA (A₃₀ in the legend) followed by the addition of TDG (200 nM). Data are mean ± S.D. (n = 3). TDG, Thymine DNA glycosylase.