Incorporation
of purine nucleotides opposite tT and base-adducted
tT in a DNA template by hPol η and comparison with the corresponding
2′-deoxynucleotides as analyzed by 15% TBE-urea PAGE. The gel
images depict incorporation of (A) dATP and (B) dGTP opposite tT,
top, O4-Me tT, center, and O4-Et tT, bottom (right panels) as well as opposite the
corresponding dTs (left panels). In each assay, 10 nM hPol η
was incubated with 150 nM DNA template:primer at 37 °C, followed
by addition of 50 μM dATP or dGTP. At the indicated time points,
aliquots were removed and mixed with quencher. In each panel, the
first lane is the 5′-FAM-labeled primer band before annealing
with the template. Each replication experiment is done in triplicate
as independent sets of experiments.