Evidence for the Kinetic Partitioning of Polymerase Activity on G-Quadruplex DNA
Evidence for the Kinetic Partitioning of Polymerase Activity on G-Quadruplex DNA
We have investigated the action of the human DNA polymerase ε (hpol ε) and η (hpol η) catalytic cores on G-quadruplex (G4) DNA substrates derived from the promoter of the c-MYC proto-oncogene. The translesion enzyme hpol η exhibits a 6.2-fold preference for binding to G4 DNA over non-G4 DNA, while hpol ε binds both G4 and non-G4 substrates with nearly equal affinity. Kinetic analysis of single-nucleotide insertion by hpol η reveals that it is able to maintain >25% activity on G4 substrates compared to non-G4 DNA substrates, even when the primer template junction is positioned directly adjacent to G22 (the first tetrad-associated guanine in the c-MYC G4 motif). Surprisingly, hpol η fidelity increases ~15-fold when copying G22. By way of comparison, hpol ε retains ~4% activity and has a 33-fold decrease in fidelity when copying G22. The fidelity of hpol η is ~100-fold greater than that of hpol ε when comparing the misinsertion frequencies of the two enzymes opposite a tetrad-associated guanine. The kinetic differences observed for the B- and Y-family pols on G4 DNA support a model in which a simple kinetic switch between replicative and TLS pols could help govern fork progress during G4 DNA replication.
- University of Arkansas for Medical Sciences United States
- Tulane University United States
DNA Replication, Base Pair Mismatch, DNA Polymerase II, DNA-Directed DNA Polymerase, Proto-Oncogene Mas, Substrate Specificity, G-Quadruplexes, Kinetics, Humans, DNA Primers, Protein Binding
DNA Replication, Base Pair Mismatch, DNA Polymerase II, DNA-Directed DNA Polymerase, Proto-Oncogene Mas, Substrate Specificity, G-Quadruplexes, Kinetics, Humans, DNA Primers, Protein Binding
1 Research products, page 1 of 1
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).41 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Average impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Top 10%
