Specific strand loss in N-2-acetylaminofluorene-modified DNA

Koffel-Schwartz, Nicole; Maenhaut-Michel, G.; Fuchs, Robert P. P.

doi:10.1016/0022-2836(87)90348-2

Cited by 65 publications

(44 citation statements)

References 31 publications

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“…(40,41). In addition, a double-stranded plasmid containing as many as 10 AAF adducts in 1 strand but none in the other strand survives about equallywell as a nondamaged molecule (36). These results indicate that SOS induction does not increase the survival of damaged doublestranded DNA molecules and that their replication proceeds efficiently provided that one strand remains undamaged.…”

Section: Resultssupporting

confidence: 47%

“…2), raising the possibility that uncoupling of the replication of the two strands occurs during TLS with a delay in the replication across the adduct, thus leading to an underrepresentation of the progeny of the damaged strand in the colony. Evidence for uncoupling of the replication of strands in the presence of adducts has been presented (36 (37,38). We have previously shown that -1 slippage mutagenesis induced by AAF adducts within runs of guanines proceeds by a mutation pathway that exhibits the same genetic requirements as UV-induced base-substitution mutagenesis.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Cellular strategies for accommodating replication-hindering adducts in DNA: control by the SOS response in Escherichia coli.

Koffel-Schwartz¹,

Coin²,

Veaute³

et al. 1996

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

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The replication of double-stranded plasmids containing a single adduct was analyzed in vivo by means of a sequence heterology that marks the two DNA strands. The single adduct was located within the sequence heterology, making it possible to distinguish trans-lesion synthesis (TLS) events from damage avoidance events in which replication did not proceed through the lesion. When the SOS system of the host bacteria is not induced, the C8-guanine adduct formed by the carcinogen N-2-acetylaminofluorene (AAF) yields less than 1% of TLS events, showing that replication does not readily proceed through the lesion. In contrast, the deacetylated adduct N-(deoxyguanosin-8-yl)-2-aminofluorene yields -70% of TLS events under both SOS-induced and uninduced conditions. These results for TLS in vivo are in good agreement with the observation that AAF blocks DNA replication in vitro, whereas aminofluorene does so only weakly. Induction of the SOS response causes an increase in TLS events through the AAF adduct ("13%). The increase in TLS is accompanied by a proportional increase in the frequency of AAF-induced frameshift mutations. However, the polymerase frameshift error rate per TLS event was essentially constant throughout the SOS response. In an SOS-induced AumuD/C strain, both TLS events and mutagenesis are totally abolished even though there is no decrease in plasmid survival. Error-free replication evidently proceeds efficiently by means of the damage avoidance pathway. We conclude that SOS mutagenesis results from increased TLS rather than from an increased frameshift error rate of the polymerase.Most mutagens and carcinogens react with the bases of DNA by forming covalent adducts that interfere with DNA metabolism if left unrepaired. Repair pathways remove these lesions: excision repair removes damaged bases or nucleotides prior to replication and post-replication repair fills in gaps formed in newly synthesized DNA strands when damaged DNA is replicated. These two major repair pathways are believed to be essentially error-free and to contribute about equally to cell survival. The effect of DNA adducts on replication has been analyzed in in vitro assays using damaged single-stranded DNA templates and purified DNA polymerases (1-6). Studies of templates containing a single adduct have shown that some adducts are absolute blocks for in vitro DNA synthesis. For example, there is no in vitro trans-lesion synthesis (TLS) by most DNA polymerases through N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (dGuo-AAF) (1), an adduct formed at the C8 position of guanine by the rodent hepatocarcinogen N-2-acetylaminofluorene (AAF) (7). However, in vivo doublestranded plasmids containing AAF adducts can replicate in excision-repair deficient hosts in an error-free or error-prone (mutagenic) manner (8-11). These observations confirm the fact that there are efficient mechanisms that rescue a blocked replication fork in vivo (12). Two such pathways are TLS involving a modified replisome and damage avoidance (DA) mechanisms that use ...

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Section: Resultssupporting

confidence: 47%

Section: Resultsmentioning

confidence: 99%

Cellular strategies for accommodating replication-hindering adducts in DNA: control by the SOS response in Escherichia coli.

Koffel-Schwartz¹,

Coin²,

Veaute³

et al. 1996

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

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“…The latter could reflect uncoupling of the first replication fork to encounter the adduct, such that repli- cation of the undamaged strand continues while replication of the damaged strand is completely or transiently blocked. Evidence exists that uncoupling can occur under some circumstances in E. coli (Koffel-Schwartz et al, 1987) 3 and during SV40 replication in vivo (Burhans et al, 1991). Alternatively, the first fork may not replicate either strand beyond the lesion, with preferential replication of the undamaged strand accomplished by the fork arriving from the other direction in the circular substrate.…”

Section: Discussionmentioning

confidence: 99%

Frequency and Fidelity of Translesion Synthesis of Site-specific N-2-Acetylaminofluorene Adducts during DNA Replication in a Human Cell Extract

Thomas

Veaute

Fuchs

et al. 1995

Journal of Biological Chemistry

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We have previously analyzed the effects of site-specific N-2-acetylaminofluorene (AAF) adducts on the efficiency and frameshift fidelity of SV40-based DNA replication in a human cell extract (Thomas, D. C., Veaute, X., Kunkel, T. A., and Fuchs, R. P. P. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 7752-7756). Here we use two sets of substrates to examine the probability of replication termination and error-free and error-prone bypass of AAF adducts. The substrates contained site-specific adducts at one of three guanines in a NarI sequence (5-GGCGCC-3) placed within the lacZ␣ reporter gene and located on the template for either leading or lagging strand replication. The presence of the adduct at any position strongly reduces the efficiency of a single round of replication in a HeLa cell extract. Product analysis reveals preferential replication of the undamaged strand and termination of replication of the damaged strand occurring one nucleotide before incorporation opposite either a leading or lagging strand adduct. Products resistant to restriction endonuclease cleavage at the adducted site were generated in amounts consistent with 16 -48% lesion bypass during replication. Most of this bypass was error-free. However, two-nucleotide deletion errors were detected in the replication products of DNA containing an AAF adduct in either the leading or lagging strand, but only when present at the third guanine position. Collectively, the data suggest that the replication apparatus in a HeLa cell extract generates a template-primer slippage error at an AAF adduct once for every 30 -100 bypass events.DNA replication in eukaryotic cells requires multiple proteins that function in an asymmetric manner to coordinately synthesize the leading and lagging strands (Kornberg and Baker, 1992). Given the asymmetry of replication of duplex DNA, unrepaired DNA adducts may have different potentials for blocking replication or promoting replication infidelity depending on whether the adduct is located on the leading or lagging strand. To examine this, we have been using the SV40 origin-dependent replication system (for review, see Stillman (1994), and references therein) as a model for human chromosomal replication. With this system, replication of undamaged DNA in mammalian cell extracts is highly accurate (Roberts and Kunkel, 1988;Hauser et al., 1988;Thomas et al., 1991). However, replication of DNA containing randomly placed cyclobutane pyrimidine dimers (CPDs) 1 is highly mutagenic Carty et al., 1993). The assay system was adapted to determine whether, as a result of the asymmetry of replication, CPDinduced errors arise at different rates during leading and lagging strand synthesis. Overall average error rates were equal for the leading and lagging strand replication machinery, with strand-specific differences in fidelity observed at some nucleotide positions .For several years, we have studied the effects of an encounter between the replication fork and the major adduct of a known carcinogen, N-2-acetylaminofluorene (AAF) located at ...

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“…However, an alternative explanation relevant to the plasmid situation that could equally account for the high proportion of 3Gϩ3 pure clones might be the preferential replication and concomitant amplification of the undamaged strand. Lesion-induced strand loss was proposed to explain the prevalence of the undamaged strand in transformants arising from the replication of vectors containing either AAF adducts (20,45) or a single cis-syn cyclobutane thymine dimer (15) in E. coli. It is not possible, with the present constructs, to distinguish between true DA events and lesioninduced strand loss.…”

Section: Tls Of the Aaf-modified Sequence (5 Gggmentioning

confidence: 99%

Analysis of Damage Tolerance Pathways in Saccharomyces cerevisiae: a Requirement for Rev3 DNA Polymerase in Translesion Synthesis

Baynton

Bresson-Roy

Fuchs

1998

Molecular and Cellular Biology

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The replication of double-stranded plasmids containing a single N-2-acetylaminofluorene (AAF) adduct located in a short, heteroduplex sequence was analyzed in Saccharomyces cerevisiae. The strains used were proficient or deficient for the activity of DNA polymerase (REV3 and rev3⌬, respectively) in a mismatch and nucleotide excision repair-defective background (msh2⌬ rad10⌬). The plasmid design enabled the determination of the frequency with which translesion synthesis (TLS) and mechanisms avoiding the adduct by using the undamaged, complementary strand (damage avoidance mechanisms) are invoked to complete replication. To this end, a hybridization technique was implemented to probe plasmid DNA isolated from individual yeast transformants by using short, 32 P-end-labeled oligonucleotides specific to each strand of the heteroduplex. In both the REV3 and rev3⌬ strains, the two strands of an unmodified heteroduplex plasmid were replicated in ϳ80% of the transformants, with the remaining 20% having possibly undergone prereplicative MSH2-independent mismatch repair. However, in the presence of the AAF adduct, TLS occurred in only 8% of the REV3 transformants, among which 97% was mostly error free and only 3% resulted in a mutation. All TLS observed in the REV3 strain was abolished in the rev3⌬ mutant, providing for the first time in vivo biochemical evidence of a requirement for the Rev3 protein in TLS.

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Specific strand loss in N-2-acetylaminofluorene-modified DNA

Cited by 65 publications

References 31 publications

Cellular strategies for accommodating replication-hindering adducts in DNA: control by the SOS response in Escherichia coli.

Cellular strategies for accommodating replication-hindering adducts in DNA: control by the SOS response in Escherichia coli.

Frequency and Fidelity of Translesion Synthesis of Site-specific N-2-Acetylaminofluorene Adducts during DNA Replication in a Human Cell Extract

Analysis of Damage Tolerance Pathways in Saccharomyces cerevisiae: a Requirement for Rev3 DNA Polymerase in Translesion Synthesis

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