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The efficiency of translesion synthesis past single styrene oxide DNA adducts in vitro is polymerase-specific.
- Source :
-
Chemical research in toxicology [Chem Res Toxicol] 1995 Apr-May; Vol. 8 (3), pp. 422-30. - Publication Year :
- 1995
-
Abstract
- In order to examine the effect of adenine N6 adducts of styrene oxide (SO) on DNA replication, 33-mer templates were constructed bearing site-specific and stereospecific SO modifications. Both R- and S-SO adducts were introduced at four different base positions within a sequence containing codons 60-62 from the human N-ras gene. The resulting eight templates were replicated in primer extension assays using the Klenow fragment, Sequenase 2.0, T4 polymerase holoenzyme, polymerase alpha, and polymerase beta. Replication of the damaged templates was analyzed under conditions defining single and/or multiple encounters between the polymerase and the substrate. Polymerization by all five enzymes was sensitive to both the local sequence context and the chirality of the SO adduct. For example, R-SO lesions placed at the third position of N-ras codon 61 were readily bypassed, whereas stereochemically-identical lesions in other sequence contexts were often poor substrates for replication. Similarly, R- and S-SO adducts introduced within identical sequences were often bypassed nonequivalently. Significantly, the degree of adduct-directed termination and translesion synthesis during replication was also dependent on the choice of polymerase. Although SO adducts directed termination either opposite the lesion or 1 base 3' to the damage using all five polymerases, templates that were poor substrates for bypass synthesis with one enzyme were often read-through much more efficiently when a different polymerase was used. Thus, the activities of these enzymes on the SO-modified substrates produced replication profiles, or "fingerprints", that were unique to each polymerase.
- Subjects :
- Animals
Bacteriophage T4 enzymology
Base Sequence
DNA Polymerase I biosynthesis
DNA Polymerase II biosynthesis
DNA-Directed DNA Polymerase drug effects
Genes, ras
Humans
Molecular Sequence Data
Rats
Templates, Genetic
Viral Proteins biosynthesis
DNA Adducts toxicity
DNA Replication drug effects
DNA-Directed DNA Polymerase biosynthesis
Epoxy Compounds toxicity
Subjects
Details
- Language :
- English
- ISSN :
- 0893-228X
- Volume :
- 8
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Chemical research in toxicology
- Publication Type :
- Academic Journal
- Accession number :
- 7578929
- Full Text :
- https://doi.org/10.1021/tx00045a014