title: Efficient and error-free replication past a minor-groove DNA adduct by the sequential action of human DNA polymerases iota and kappa.
abstract: DNA polymerase iota (Poliota) is a member of the Y family of DNA polymerases, which promote replication through DNA lesions. The role of Poliota in lesion bypass, however, has remained unclear. Poliota is highly unusual in that it incorporates nucleotides opposite different template bases with very different efficiencies and fidelities. Since interactions of DNA polymerases with the DNA minor groove provide for the nearly equivalent efficiencies and fidelities of nucleotide incorporation opposite each of the four template bases, we considered the possibility that Poliota differs from other DNA polymerases in not being as sensitive to distortions of the minor groove at the site of the incipient base pair and that this enables it to incorporate nucleotides opposite highly distorting minor-groove DNA adducts. To check the validity of this idea, we examined whether Poliota could incorporate nucleotides opposite the gamma-HOPdG adduct, which is formed from an initial reaction of acrolein with the N(2) of guanine. We show here that Poliota incorporates a C opposite this adduct with nearly the same efficiency as it does opposite a nonadducted template G residue. The subsequent extension step, however, is performed by Polkappa, which efficiently extends from the C incorporated opposite the adduct. Based upon these observations, we suggest that an important biological role of Poliota and Polkappa is to act sequentially to carry out the efficient and accurate bypass of highly distorting minor-groove DNA adducts of the purine bases.
authors.affiliation: University of Texas Medical Branch, Sealy Center for Molecular Science, 6.104 Blocker Medical Research Building, 11th and Mechanic St., Galveston, TX 77555-1061, USA.
authors.forename: M Todd
authors.initials: MT
authors.lastname: Washington
authors.forename: Irina G
authors.initials: IG
authors.lastname: Minko
authors.forename: Robert E
authors.initials: RE
authors.lastname: Johnson
authors.forename: William T
authors.initials: WT
authors.lastname: Wolfle
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Harris
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Lloyd
authors.forename: Satya
authors.initials: S
authors.lastname: Prakash
authors.forename: Louise
authors.initials: L
authors.lastname: Prakash
mesh_terms: D020029:Base Pairing; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D003570:Cytidine Triphosphate / Q000378:metabolism; D018736:DNA Adducts / Q000737:chemistry / Q000235:genetics*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D003849:Deoxyguanosine / Q000031:analogs & derivatives*; D006801:Humans; D007700:Kinetics; D009687:Nuclear Proteins / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D009711:Nucleotides / Q000378:metabolism
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D018736:DNA Adducts; D009687:Nuclear Proteins; D009711:Nucleotides; C452228:hydroxy-1,N(2)-propanodeoxyguanosine; D003570:Cytidine Triphosphate; C407743:DNA polymerase mu; D004259:DNA-Directed DNA Polymerase; C118146:TENT4A protein, human; D003849:Deoxyguanosine