title: Specificity of mutations induced by incorporation of oxidized dNTPs into DNA by human DNA polymerase eta.
abstract: Aberrant oxidation is a property of many tumor cells. Oxidation of DNA precursors, i.e., deoxynucleotide triphosphates (dNTPs), as well as DNA is a major cause of genome instability. Here, we report that human DNA polymerase eta (h Poleta) incorporates oxidized dNTPs, i.e., 2-hydroxy-2'-deoxyadenosine 5'-triphosphate (2-OH-dATP) and 8-hydroxy-2'-deoxyguanosine 5'-triphosphate (8-OH-dGTP), into DNA in an erroneous and efficient manner, thereby inducing various types of mutations during in vitro gap-filling DNA synthesis. When 2-OH-dATP was present at a concentration equal to those of the four normal dNTPs in the reaction mixture, DNA synthesis by h Poleta enhanced the frequency of G-to-T transversions eight-fold higher than that of the transversions in control where only the normal dNTPs were present. When 8-OH-dGTP was present at an equimolar concentration to the normal dNTPs, it enhanced the frequency of A-to-C transversions 17-fold higher than the control. It also increased the frequency of C-to-A transversions about two-fold. These results suggest that h Poleta incorporates 2-OH-dATP opposite template G and incorporates 8-OH-dGTP opposite template A and slightly opposite template C during DNA synthesis. Besides base substitutions, h Poleta enhanced the frequency of single-base frameshifts and deletions with the size of more than 100 base pairs when 8-OH-dGTP was present in the reaction mixture. Since h Poleta is present in replication foci even without exogenous DNA damage, we suggest that h Poleta may be involved in induction of various types of mutations through the erroneous and efficient incorporation of oxidized dNTPs into DNA in human cells.
authors.affiliation: Division of Genetics and Mutagenesis, National Institute of Health Sciences, Setagaya-ku, Tokyo 158-8501, Japan.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Hidaka
authors.forename: Masami
authors.initials: M
authors.lastname: Yamada
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kamiya
authors.forename: Chikahide
authors.initials: C
authors.lastname: Masutani
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Harashima
authors.forename: Fumio
authors.initials: F
authors.lastname: Hanaoka
authors.forename: Takehiko
authors.initials: T
authors.lastname: Nohmi
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics* / Q000378:metabolism; D003848:Deoxyguanine Nucleotides / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D000099270:Y-Family DNA Polymerases
chemical_list: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000255:Adenosine Triphosphate; D004269:DNA, Bacterial; D004259:DNA-Directed DNA Polymerase; D003848:Deoxyguanine Nucleotides; C095141:2-hydroxydeoxyadenosine triphosphate; C521293:8-hydroxy-2'-deoxyguanosine 5'-triphosphate; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases