Erroneous incorporation of oxidized DNA precursors by Y‐family DNA polymerases

Abstract

Deranged oxidative metabolism is a property of many tumour cells. Oxidation of the deoxynucleotide triphosphate (dNTP) pool, as well as DNA, is a major cause of genome instability. Here, we report that two Y-family DNA polymerases of the archaeon Sulfolobus solfataricus strains P1 and P2 incorporate oxidized dNTPs into nascent DNA in an erroneous manner: the polymerases exclusively incorporate 8-OH-dGTP opposite adenine in the template, and incorporate 2-OHdATP opposite guanine more efficiently than opposite thymine. The rate of extension of the nascent DNA chain following on from these incorporated analogues is only slightly reduced. These DNA polymerases have been shown to bypass a variety of DNA lesions. Thus, our results suggest that the Y-family DNA polymerases promote mutagenesis through the erroneous incorporation of oxidized dNTPs during DNA synthesis, in addition to facilitating translesion DNA synthesis. We also report that human DNA polymerase η, a human Y-family DNA polymerase, incorporates the oxidized dNTPs in a similar erroneous manner.

Roles of specialized DNA polymerases in mutagenesis by 8-hydroxyguanine in human cells

“…This speculation is consistent with the highly erroneous incorporation of 8-OH-dGTP opposite A by this DNA pol in vitro [51,52].…”

Measurement of 7,8-dihydro-8-oxo-2′-deoxyguanosine metabolism in MCF-7 cells at low concentrations using accelerator mass spectrometry

“…Irregular expression of some DNA polymerases, such as pol ␤ or pol , may account for the observed efficient incorporation (40,41). Although 8-oxodGTP is a poor substrate for most replicative DNA polymerases (42), it is important to consider that our results were obtained in a cellular environment that likely has cofactors or even unknown polymerases that allow efficient incorporation of 8-oxodGTP.…”

Mutagenicities of 8-Hydroxyguanine and 2-Hydroxyadenine Produced by Reactive Oxygen Species

“…These explanations agree with results obtained by in vitro DNA synthesis experiments. 4,36,[40][41][42][43] As discussed in the previous paper, 47) the DNA pol-specific mispairing properties of 2-OH-dATP may be derived from the presence of the hydrophobicity-dependent enol-keto equilibrium of 2-OH-Ade, and from the possibility of adopting the syn conformation.…”

“…We incubated synthetic ODN templates with DNA polymerases in the presence of 2-OH-dATP. E. coli DNA pol III a (catalytic) subunit and human DNA pol h inserted 2-OH-dATP opposite T and G. 42,43) In contrast, mammalian pol a incorporated 2-OHdATP opposite T and C. 4) Interestingly, the misincorporation of nucleotides opposite 2-OH-Ade in DNA templates is also DNA pol-specific (see above). We also examined the misincorporation of these oxidized purine nucleotides in a gap-filling reaction by the E. coli DNA pol III holoenzyme.…”