Translesion replication of benzo[a]pyrene and benzo[c]phenanthrene diol epoxide adducts of deoxyadenosine and deoxyguanosine by human DNA polymerase iota.
Human DNA polymerase iota (poliota) is a Y-family polymerase whose cellular function is presently unknown. Here, we report on the ability of poliota to bypass various stereoisomers of benzo[a]pyrene (BaP) diol epoxide (DE) and benzo[c]phenanthrene (BcPh) DE adducts at deoxyadenosine (dA) or deoxyguanosine (dG) bases in four different template sequence contexts in vitro. We find that the BaP DE dG adducts pose a strong block to poliota-dependent replication and result in a high frequency of base misincorporations. In contrast, misincorporations opposite BaP DE and BcPh DE dA adducts generally occurred with a frequency ranging between 2 x 10(-3) and 6 x 10(-4). Although dTMP was inserted efficiently opposite all dA adducts, further extension was relatively poor, with one exception (a cis opened adduct derived from BcPh DE) where up to 58% extension past the lesion was observed. Interestingly, another human Y-family polymerase, polkappa, was able to extend dTMP inserted opposite a BaP DE dA adduct. We suggest that poliota might therefore participate in the error-free bypass of DE-adducted dA in vivo by predominantly incorporating dTMP opposite the damaged base. In many cases, elongation would, however, require the participation of another polymerase more specialized in extension, such as polkappa.
Frank
Ekaterina G
EG
Section on DNA Replication, Repair, and Mutagenesis, Building 6, Room 1A13, National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892-2725 USA.
Sayer
Jane M
JM
Kroth
Heiko
H
Ohashi
Eiji
E
Ohmori
Haruo
H
Jerina
Donald M
DM
Woodgate
Roger
R
D001483:Base Sequence; D018736:DNA Adducts / Q000096:biosynthesis* / Q000737:chemistry*; D019951:DNA Polymerase beta / Q000378:metabolism; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D011506:Proteins / Q000378:metabolism; D013237:Stereoisomerism; D013698:Templates, Genetic; D000094769:DNA Polymerase iota; D000099270:Y-Family DNA Polymerases
D018736:DNA Adducts; D019951:DNA Polymerase beta; D004259:DNA-Directed DNA Polymerase; D011506:Proteins; D000094769:DNA Polymerase iota; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases; C000722070:POLI protein, human