Figure 2.

Single nucleotide insertion curves for Polα, Polβ and Polη. Individual reaction mixtures containing template:primer substrate and increasing concentrations of one of each dNTP were incubated with Polα, Polβ and Polη, reaction products were separated on polyacrylamide gels, and the percent of extended primer was calculated from band intensities; a non-linear fit was applied to obtain rectangular hyperbolic insertion curves, as described in Materials and Methods. Mean values from two to five independent experiments are shown, and the position of codon 12 is highlighted. (A) Replication of unmodified control template T0. (B) Replication in the direct mutagenesis system: template T1 containing 8-OH-G in the first position of codon 12. (C) ‘Action-at- a-distance’ mutagenesis system: replication of template T2 containing G in the first position of codon 12 and 8-OH-G in the second position. (D) Replication of template T3 containing two adjacent 8-OH-G residues in codon 12.