Mechanism of translesion synthesis past an equine estrogen-DNA adduct by Y-family DNA polymerases.
4-Hydroxyequilenin (4-OHEN)-dC is a major, potentially mutagenic DNA adduct induced by equine estrogens used for hormone replacement therapy. To study the miscoding property of 4-OHEN-dC and the involvement of Y-family human DNA polymerases (pols) eta, kappa and iota in that process, we incorporated 4-OHEN-dC into oligodeoxynucleotides and used them as templates in primer extension reactions catalyzed by pol eta, kappa and iota. Pol eta inserted dAMP opposite 4-OHEN-dC, accompanied by lesser amounts of dCMP and dTMP incorporation and base deletion. Pol kappa promoted base deletions as well as direct incorporation of dAMP and dCMP. Pol iota worked in conjunction with pol kappa, but not with pol eta, at a replication fork stalled by the adduct, resulting in increased dTMP incorporation. Our results provide a direct evidence that Y-family DNA pols can switch with one another during synthesis past the lesion. No direct incorporation of dGMP, the correct base, was observed with Y-family enzymes. The miscoding potency of 4-OHEN-dC may be associated with the development of reproductive cancers observed in women receiving hormone replacement therapy.
Yasui
Manabu
M
Laboratory of Chemical Biology, Department of Pharmacological Sciences, State University of New York at Stony Brook, Stony Brook, NY 11794-8651, USA.
Suzuki
Naomi
N
Liu
Xiaoping
X
Okamoto
Yoshinori
Y
Kim
Sung Yeon
SY
Laxmi
Y R Santosh
YR
Shibutani
Shinya
S
D000818:Animals; D001483:Base Sequence; D002384:Catalysis; D018736:DNA Adducts; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry*; D004855:Equilenin / Q000737:chemistry*; D004857:Equilin / Q000737:chemistry*; D004967:Estrogens / Q000737:chemistry*; D005260:Female; D020249:Hormone Replacement Therapy / Q000379:methods; D006736:Horses; D006801:Humans; D007700:Kinetics; D008956:Models, Chemical; D008969:Molecular Sequence Data
D018736:DNA Adducts; D004967:Estrogens; D004857:Equilin; D004259:DNA-Directed DNA Polymerase; D004855:Equilenin