Translesional synthesis on a DNA template containing a single stereoisomer of dG-(+)- or dG-(-)-anti-BPDE (7, 8-dihydroxy-anti-9, 10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene

Shibutani, Shinya; Margulis, Leonid A.; Geacintov, Nicholas E.; Grollman, Arthur P.

doi:10.1021/bi00080a027

Cited by 113 publications

(182 citation statements)

References 70 publications

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“…Cleavage products containing a trans-S adduct migrated slightly more slowly than did the corresponding fragments containing a trans-R adduct. Differences in electrophoretic migration for oligonucleotides containing R-versus S-BaP DE adducts have been noted previously (31,32).…”

Section: Accumulation Of Top1-mediated Dna Cleavage Complexes By Bap mentioning

confidence: 60%

Position-specific trapping of topoisomerase I–DNA cleavage complexes by intercalated benzo[ a ]- pyrene diol epoxide adducts at the 6-amino group of adenine

Pommier

Laco

Kohlhagen

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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DNA topoisomerase I (top1) is the target of potent anticancer agents, including camptothecins and DNA intercalators, which reversibly stabilize (trap) top1 catalytic intermediates (cleavage complexes). The aim of the present study was to define the structural relationship between the site(s) of covalently bound intercalating agents, whose solution conformations in DNA are known, and the site(s) of top1 cleavage. Two diastereomeric pairs of oligonucleotide 22-mers, derived from a sequence used to determine the crystal structure of top1-DNA complexes, were synthesized. One pair contained either a trans-opened 10R-or 10S-benzo[a]pyrene 7,8-diol 9,10-epoxide adduct at the N 6 -amino group of a central 2 -deoxyadenosine residue in the scissile strand, and the other pair contained the same two adducts in the nonscissile strand. These adducts were derived from the (؉)-(7R,8S,9S,10R)-and (؊)-(7S,8R,9R,10S)-7,8-diol 9,10-epoxides in which the benzylic 7-hydroxyl group and the epoxide oxygen are trans. On the basis of analogy with known solution conformations of duplex oligonucleotides containing these adducts, we conclude that top1 cleavage complexes are trapped when the hydrocarbon adduct is intercalated between the base pairs flanking a preexisting top1 cleavage site, or between the base pairs immediately downstream (3 relative to the scissile strand) from this site. We propose a model with the ؉1 base rotated out of the duplex, and in which the intercalated adduct prevents religation of the corresponding nucleotide at the 5 end of the cleaved DNA. These results suggest mechanisms whereby intercalating agents interfere with the normal function of human top1. D NA topoisomerase I (top1) is an essential enzyme in higher eukaryotes (1, 2). It can relax DNA supercoiling and relieve torsional strain during DNA processing, including replication, transcription, and repair. It can also perform intermolecular religation leading to DNA recombinations (3, 4). The catalytic intermediate of top1 is a cleavage complex in which a tyrosine (Tyr-723 for human top1) in the enzyme attacks a DNA phosphodiester and forms a covalent bond to the phosphorus at the 3Ј side of the cleavage site while a 5Ј-hydroxyl is generated at the other side (1, 2). The reaction occurs with short duplex oligodeoxynucleotides (5, 6), as evidenced by recent crystal structures of top1-DNA complexes (7,8).top1 is the cellular target of several anticancer drugs, including the camptothecins, which have recently been approved by the Food and Drug Administration for the treatment of colon and ovarian carcinomas. The anticancer activity of these drugs results from the trapping of top1 cleavage complexes such that the enzyme is reversibly inactivated as it cleaves DNA (9-11). These agents are often referred to as ''top1 poisons.'' They represent an exemplary case of pharmacological interference whereby the drug stabilizes the interactions of two macromolecules (i.e., top1 and DNA) by formation of a ternary complex. Because of the clinical efficacy of camptothecins, no...

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Section: Accumulation Of Top1-mediated Dna Cleavage Complexes By Bap mentioning

confidence: 60%

Position-specific trapping of topoisomerase I–DNA cleavage complexes by intercalated benzo[ a ]- pyrene diol epoxide adducts at the 6-amino group of adenine

Pommier

Laco

Kohlhagen

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

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“…For example, in the case of KF Ϫ , extension beyond the lesion is more than 1 order of magnitude less efficient than insertion of any of the four dNTPs opposite the lesion site (21,27,28). Human pol , yeast pol , or the combined activities of both polymerases are not able to fully bypass any of the stereoisomeric [BP]-N 2 -dG or [BP]-N 6 -dA lesions studied and thus resemble some of the classical polymerases in terms of their lack of ability to bypass these lesions.…”

Section: Discussionmentioning

confidence: 99%

trans-Lesion Synthesis Past Bulky Benzo[a]pyrene Diol Epoxide N2-dG and N6-dA Lesions Catalyzed by DNA Bypass Polymerases

Rechkoblit

Zhang

Guo

et al. 2002

Journal of Biological Chemistry

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The effectiveness of in vitro primer elongation reactions catalyzed by human bypass DNA polymerases (hDinB1), pol (hRad30A), pol (hRad30B), and yeast pol (Rev3 and Rev7) in site-specifically modified template oligonucleotide strands were studied in vitro. The templates contained single bulky lesions derived from the trans-addition of the mutagenic (؉)-or (؊)-enantiomers of r7,t8-dihydroxy-t9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (a metabolite of the environmental carcinogen benzo[a]pyrene), to the exocyclic amino groups of guanine or adenine in oligonucleotide templates 33, or more, bases long. In "running start" primer extension reactions, pol effectively bypassed both the stereoisomeric (؉)-and (؊)-trans-guanine adducts but not the analogous adenine adducts. In sharp contrast, pol , which exhibits considerable sequence homology with pol (both belong to the group of Y family polymerases), is partially blocked by the guanine adducts and the (؊)-trans-adenine adduct, although the stereoisomeric (؉)-trans-adenine adduct is more successfully bypassed. Neither pol nor pol , either alone or in combination, were effective in trans-lesion synthesis past the same adducts. In all cases, the fidelity of insertion is dependent on adduct stereochemistry and structure. Generally, error-free nucleotide insertion opposite the lesions tends to depend more on adduct stereochemistry than error-prone insertion. None of the polymerases tested are a universal bypass polymerase for the stereoisomeric bulky polycyclic aromatic hydrocarbon-DNA adducts derived from anti-BPDE.Several new prokaryotic and eukaryotic DNA polymerases (pol) 1 involved in trans-lesional synthesis have been recently identified (reviewed in Refs. 1-5). The functional characteristics of the UmuC/DinB/Rev1p/Rad30 DNA polymerases belonging to the Y family of DNA polymerases (5) have been extensively investigated (6 -11). These polymerases are able to bypass a variety of DNA lesions in vitro (8,(12)(13)(14)(15)(16)(17)(18)(19)(20) that are known to block replication catalyzed by "classical" polymerases such as pol ␣, pol ␤, phage T7, the Klenow fragment of pol I from Escherichia coli, and human immunodeficiency virusreverse transcriptase, etc. (see Refs. 21-18 for example).The efficiencies and fidelities of trans-lesion synthesis catalyzed by Y family polymerases vary significantly among the different subfamilies and also depend remarkably on the type of DNA damage. Purified human pol (DinB1, 870 amino acids in size) efficiently bypasses (Ϫ)-trans-[BP]-N 2 -dG adducts (bulky lesions derived from the binding of the mutagen r7,t8-dihydroxy-t9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene ((ϩ)-or (Ϫ)-anti-BPDE) to the exocyclic amino groups of guanine and adenine residues in DNA (Scheme 1) with the insertion of a C opposite the lesion (12). A truncated form of pol , a 560-amino acid form pol (⌬C), missing motifs VIIa and VIIb and obtained from a baculovirus expression system, also bypasses the (ϩ)- trans-[BP]-N2 -dG adduct (29). Human pol also bypasses 8-oxo-dG lesio...

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“…The stereochemistry of BPDE has an influence on its potent mutagenic and carcinogenic properties (11)(12)(13)(14). It has been shown that BPDE-adducted DNA blocks synthesis by a variety of DNA polymerases (15)(16)(17)(18)(19). Several studies have also demonstrated that BPDE adducts in DNA impede transcription (20 -27).…”

mentioning

confidence: 99%

Highly Mutagenic Bypass Synthesis by T7 RNA Polymerase of Site-specific Benzo[a]pyrene Diol Epoxide-adducted Template DNA

Remington

Bennett

Harris

et al. 1998

Journal of Biological Chemistry

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We have previously developed an in vitro system that allows quantitative evaluation of the fidelity of transcription during synthesis on a natural template in the presence of all four nucleotides. Here, we have employed this system using a TAA ochre codon reversion assay to examine the fidelity of transcription by T7 RNA polymerase past an adenine residue adducted at the N 6 -position with (؊)-anti-trans-or (؉)-anti-trans-benzo-[a]pyrene diol epoxide (BPDE). T7 RNAP was capable of transcribing past either BPDE isomer to generate fulllength run-off transcripts. The extent of bypass was found to be 32% for the (؊)-anti-trans-isomer and 18% for the (؉)-anti-trans-isomer. Transcription past both adducts was highly mutagenic. The reversion frequency of bypass synthesis of the (؊)-anti-trans-isomer was elevated 11,000-fold and that of the (؉)-anti-trans-isomer 6000-fold, relative to the reversion frequency of transcription on unadducted template. Adenine was misinserted preferentially, followed by guanine, opposite the adenine adducted with either BPDE isomer. Although base substitution errors were by far the most frequent mutation on the adducted template, three-and six-base deletions were also observed. These results suggest that transcriptional errors, particularly with regard to damage bypass, may contribute to the mutational burden of the cell.It is well documented that genomic instability can result from errors made during DNA replication, repair, or recombination. However, less is known concerning the effects of inaccurate transcription and/or translation on the integrity of the genetic information. Transcriptional and translational errors may lead to production of mutant proteins. If the defective protein is involved in DNA replication or repair, then even its transient presence may result in permanent changes in the cell's DNA. In fact, a recent paper by Slupska et al. (1) suggests that translational miscoding may result in a mutator phenotype in Escherichia coli due to production of mutant DNA polymerases with dysfunctional proofreading activity.A likely source of transcriptional errors is damage to the DNA template and/or ribonucleotide pools. Some DNA lesions, such as UV light-induced cyclobutane dimers, block the progression of RNA polymerase (2). Such lesions have been shown to be preferentially repaired, relative to other parts of the genome, when present in the template strand of an actively transcribed gene (3-4). However, lesions that are bypassed by the polymerase may result in erroneous transcripts that, if translated, will give rise to mutant proteins. The biological consequences of transcriptional mutagenesis may be particularly significant in nondividing cells in which some mutant proteins may accumulate over time. Evidence presented by van Leeuwen et al. (5) points to transcription errors as a possible source of a mutant form of ␤-amyloid precursor protein found in neurons of Alzheimer's and Down's syndrome patients. Deposition of this mutant protein in neuritic plaque is probably involved in...

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Translesional synthesis on a DNA template containing a single stereoisomer of dG-(+)- or dG-(-)-anti-BPDE (7, 8-dihydroxy-anti-9, 10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene

Cited by 113 publications

References 70 publications

Position-specific trapping of topoisomerase I–DNA cleavage complexes by intercalated benzo[ a ]- pyrene diol epoxide adducts at the 6-amino group of adenine

Position-specific trapping of topoisomerase I–DNA cleavage complexes by intercalated benzo[ a ]- pyrene diol epoxide adducts at the 6-amino group of adenine

trans-Lesion Synthesis Past Bulky Benzo[a]pyrene Diol Epoxide N2-dG and N6-dA Lesions Catalyzed by DNA Bypass Polymerases

Highly Mutagenic Bypass Synthesis by T7 RNA Polymerase of Site-specific Benzo[a]pyrene Diol Epoxide-adducted Template DNA

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