title: Translesion synthesis past acrolein-derived DNA adduct, gamma -hydroxypropanodeoxyguanosine, by yeast and human DNA polymerase eta.
abstract: gamma-Hydroxy-1,N(2)-propano-2'deoxyguanosine (gamma-HOPdG) is a major deoxyguanosine adduct derived from acrolein, a known mutagen. In vitro, this adduct has previously been shown to pose a severe block to translesion synthesis by a number of polymerases (pol). Here we show that both yeast and human pol eta can incorporate a C opposite gamma-HOPdG at approximately 190- and approximately 100-fold lower efficiency relative to the control deoxyguanosine and extend from a C paired with the adduct at approximately 8- and approximately 19-fold lower efficiency. Although DNA synthesis past gamma-HOPdG by yeast pol eta was relatively accurate, the human enzyme misincorporated nucleotides opposite the lesion with frequencies of approximately 10(-1) to 10(-2). Because gamma-HOPdG can adopt both ring closed and ring opened conformations, comparative replicative bypass studies were also performed with two model adducts, propanodeoxyguanosine and reduced gamma-HOPdG. For both yeast and human pol eta, the ring open reduced gamma-HOPdG adduct was less blocking than gamma-HOPdG, whereas the ring closed propanodeoxyguanosine adduct was a very strong block. Replication of DNAs containing gamma-HOPdG in wild type and xeroderma pigmentosum variant cells revealed a somewhat decreased mutation frequency in xeroderma pigmentosum variant cells. Collectively, the data suggest that pol eta might potentially contribute to both error-free and mutagenic bypass of gamma-HOPdG.
authors.affiliation: Sealy Center for Molecular Science, University of Texas Medical Branch, Galveston 77555, USA.
authors.forename: Irina G
authors.initials: IG
authors.lastname: Minko
authors.forename: M Todd
authors.initials: MT
authors.lastname: Washington
authors.forename: Manorama
authors.initials: M
authors.lastname: Kanuri
authors.forename: Louise
authors.initials: L
authors.lastname: Prakash
authors.forename: Satya
authors.initials: S
authors.lastname: Prakash
authors.forename: R Stephen
authors.initials: RS
authors.lastname: Lloyd
mesh_terms: D000171:Acrolein / Q000378:metabolism / Q000633:toxicity*; D018736:DNA Adducts / Q000737:chemistry / Q000378:metabolism*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000502:physiology*; D003849:Deoxyguanosine / Q000378:metabolism*; D006801:Humans; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D000094769:DNA Polymerase iota
chemical_list: D018736:DNA Adducts; D029701:Saccharomyces cerevisiae Proteins; D000171:Acrolein; D004259:DNA-Directed DNA Polymerase; D003849:Deoxyguanosine; D000094769:DNA Polymerase iota; C000722070:POLI protein, human