FIGURE 4.

TFIIS is not a transcription bypass factor for mammalian RNAPII at the N²-Et-dG lesion. a, TFIIS was added to the running start reaction at increasing concentrations. The nucleotide opposite the lesion is removed when TFIIS is presented at the higher concentration (1.0- and 10-fold). Samples in lanes marked IIS were incubated with the amount of TFIIS used in the 10-fold ratio lanes but no RNAPII. b, a 11-mer RNA primer is annealed to the template, where a cytosine on the 3′ end is opposite either a guanine or a N²-Et-dG lesion base. c, increasing concentrations of TFIIS stimulate transcript cleavage by 2 nucleotides with either the dG or N²-Et-dG template. All of the incubations were for 40 min.