Error spectra of single base change by pol ζ alone and with accessory proteins. (A) Pol ζ alone with lacZα (+) strand as template in the forward direction: DNA synthesis fidelity assay was performed with gapped M13mp2 substrate that contained a portion of the lacZ gene in the 461 nt gap region. Error changes generated by pol ζ near the M13mp2 lacZ target sequence are shown above the bottom template sequence. The base substitution mutations are shown as the base changed to, single nucleotide deletions are shown as triangles and additions are shown as the plus sign and the base added. The lacZ(+) strand in forward direction is shown, with the transcriptional start site designated as position 1 and the first 53 codons displayed as triplets except the bases introduced during cloning (positions 194–198). The changes colored in gray are phenotypically silent and were found as hitchhikers in the mutants with detectable mutations. The numbers next to the A175G and C196G changes are base substitution error rates at these positions. (B) Pol ζ alone with lacZα(−) strand as template in the reverse direction. (C) Pol ζ and PCNA/RFC with lacZα (+) strand as template in the forward direction. (D) Pol ζ and RPA with lacZα(+) strand as template in the forward direction. (E) Pol ζ, PCNA/RFC and RPA with lacZα(+) strand as template in the forward direction. (F) Pol ζ, PCNA/RFC and RPA with lacZα(−) strand as template in the reverse direction.

Comparison of pol ζ base substitution error rates with and without accessory proteins for all 12 possible mismatches. Some error rates are reported as less than or equal to values (indicated by an asterisk above the bar).