title: Polymerase incorporation and miscoding properties of 5-chlorouracil.
abstract: Inflammation-mediated hypochlorous acid (HOCl) can damage DNA, DNA precursors, and other biological molecules, thereby producing an array of damage products such as 5-chlorouracil (ClU). In this study, we prepared and studied 5-chloro-2'-deoxyuridine (CldU) and ClU-containing oligonucleotide templates. We demonstrate that human K-562 cells grown in culture with 10 muM CldU incorporate substantial amounts of CldU without significant toxicity. When in the template, ClU residues pair with dATP but also with dGTP, in a pH-dependent manner with incorporation by human polymerase beta, avian myeloblastosis virus reverse transcriptase (AMV-RT), and Escherichia coli Klenow fragment (exo(-)) polymerase. The enhanced miscoding of ClU is attributed to the electron-withdrawing 5-chlorine substituent that promotes the formation of an ionized ClU-G mispair. When mispaired with G, ClU is targeted for removal by human glycosylases. The formation, incorporation, and repair of ClU could promote transition mutations and other forms of heritable DNA damage.
authors.affiliation: Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, California 92350, USA.
authors.forename: Cherine H
authors.initials: CH
authors.lastname: Kim
authors.forename: Agus
authors.initials: A
authors.lastname: Darwanto
authors.forename: Jacob A
authors.initials: JA
authors.lastname: Theruvathu
authors.forename: Jason L
authors.initials: JL
authors.lastname: Herring
authors.forename: Lawrence C
authors.initials: LC
authors.lastname: Sowers
mesh_terms: D020137:Base Pair Mismatch; D004249:DNA Damage; D045647:DNA Glycosylases; D053843:DNA Mismatch Repair; D004256:DNA Polymerase I / Q000378:metabolism; D019951:DNA Polymerase beta / Q000378:metabolism*; D003857:Deoxyuridine / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D020014:K562 Cells; D007700:Kinetics; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D014498:Uracil / Q000031:analogs & derivatives* / Q000633:toxicity
chemical_list: C012244:5-chloro-2'-deoxyuridine; D014498:Uracil; C010889:5-chlorouracil; D012194:RNA-Directed DNA Polymerase; D004256:DNA Polymerase I; D019951:DNA Polymerase beta; D045647:DNA Glycosylases; D003857:Deoxyuridine