FIG. 4.

Base pairing specificity of human Polι. (A) DNA templates used for polymerase assays. Each DNA template (Temp) was annealed separately with the 17-mer primer that was labeled at its 5′ end with ³²P as indicated by an asterisk. (B and C) Polymerase assays were performed with 50 fmol of DNA and 3.7 ng of human Polι in the presence of a single dNTP or all four dNTPs (N₄) as indicated. Lanes 1 and 7, controls without Polι. DNA size markers in nucleotides are indicated on the left. (D) The primed DNA template (from the human p53 gene sequence) as indicated on the right was incubated with purified human Polβ (23 ng) or human Polι (1 ng). Primer extension assays were performed with either dATP (A), dCTP (C), dTTP (T), or dGTP (G) or all four dNTPs (N₄) as indicated. Quantitation of extended primers is shown below the gels.