Mutations induced in the hypoxanthine phosphoribosyl transferase gene by three urban air pollutants: acetaldehyde, benzo[a]pyrene diolepoxide, and ethylene oxide.

Lambert, Bo; Andersson, Björn; Bastlová, Tatiana; Hou, Sai‐Mei; Hellgren, Dennis; Kolman, Ada

doi:10.1289/ehp.94102s4135

Cited by 11 publications

(7 citation statements)

References 39 publications

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“…mutations are blind to accurate TLS and therefore cannot score most TLS events across BP-G. The main mutagenic event was a GC→ΤΑ transversion caused by misinsertion of an A opposite the BP-G, consistent with previous results obtained with plasmid model systems (28,(36)(37)(38) and with chromosomal mutagenesis assays monitoring BP-induced mutations in chromosomal reporter genes (39,40).…”

Section: Discussionsupporting

confidence: 87%

Genomic assay reveals tolerance of DNA damage by both translesion DNA synthesis and homology-dependent repair in mammalian cells

Izhar

Ziv

Cohen

et al. 2013

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

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DNA lesions can block replication forks and lead to the formation of single-stranded gaps. These replication complications are mitigated by DNA damage tolerance mechanisms, which prevent deleterious outcomes such as cell death, genomic instability, and carcinogenesis. The two main tolerance strategies are translesion DNA synthesis (TLS), in which low-fidelity DNA polymerases bypass the blocking lesion, and homology-dependent repair (HDR; postreplication repair), which is based on the homologous sister chromatid. Here we describe a unique high-resolution method for the simultaneous analysis of TLS and HDR across defined DNA lesions in mammalian genomes. The method is based on insertion of plasmids carrying defined site-specific DNA lesions into mammalian chromosomes, using phage integrase-mediated integration. Using this method we show that mammalian cells use HDR to tolerate DNA damage in their genome. Moreover, analysis of the tolerance of the UV light-induced 6-4 photoproduct, the tobacco smokeinduced benzo[a]pyrene-guanine adduct, and an artificial trimethylene insert shows that each of these three lesions is tolerated by both TLS and HDR. We also determined the specificity of nucleotide insertion opposite these lesions during TLS in human genomes. This unique method will be useful in elucidating the mechanism of DNA damage tolerance in mammalian chromosomes and their connection to pathological processes such as carcinogenesis.error-prone DNA repair | homologous recombination repair | recombinational repair D NA damage is abundant, caused by both external agents such as sunlight and tobacco smoke and intracellular byproducts of metabolism, amounting to about 50,000 lesions per day per cell (1). Despite the presence of effective DNA repair mechanisms that eliminate lesions and restore the original DNA sequence, DNA replication often encounters unrepaired lesions that have escaped repair. These DNA damages may cause arrest of replication forks and the generation of postreplication gaps (2, 3). To complete replication and prevent the formation of double-strand breaks, which are highly deleterious, cells use DNA damage tolerance (DDT) mechanisms. These include translesion DNA synthesis (TLS) and homology-dependent repair (HDR), which enable bypass of the lesions and completion of replication, without removing the lesions from DNA. HDR uses the sequence from the intact sister chromatid to patch the single-stranded template region carrying the lesion. [We term HDR the pathways of DNA damage tolerance that rely on the homologous sister chromatid, also termed postreplication repair (PRR), damage avoidance, template switch, copy choice recombination, and homologous recombination repair.] This is carried out either by physical transfer of the segment complementary to the damaged template [also termed homologous recombination repair (HRR)] or by copying the complementary strand from the sister chromatid (template switch or postreplication repair). TLS employs specialized low-fidelity DNA polymerases to replicate across ...

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Section: Discussionsupporting

confidence: 87%

Genomic assay reveals tolerance of DNA damage by both translesion DNA synthesis and homology-dependent repair in mammalian cells

Izhar

Ziv

Cohen

et al. 2013

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

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“…Published evidence suggests that this metabolite forms complexes with serum albumin and lipoprotein, which enhance its stabilization and transportation (Ginsberg & Atherholt, 1990) throughout the circulation and cause damage in tissues/organs that are deficient in PAH-metabolizing enzymes (Garg et al, 1993). Benzo[a]pyrene diol epoxide was known to induce mutations in the hypoxanthine phosphoribosyl transferase gene (Lambert et al, 1994) and c-Ha-ras-1 proto-oncogene (Ramos et al, 1998). This metabolite has also been reported to induce DNA adducts in codons 157, 248, and 273 in the p53 gene, sites that are the major mutational targets in human lung cancers (Denissenko et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

TOXICOKINETICS OF INHALED BENZO[a]PYRENE: Plasma and Lung Bioavailability

Ramesh¹,

Greenwood²,

Inyang³

et al. 2001

Inhalation Toxicology

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Bioavailability and toxicokinetic studies are essential in order to establish dose-response relationships of widely distributed environmental toxicants such as benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon. Fischer 344 rats were exposed for 4 h (via nose-only inhalation) to aerosol exposure concentrations of 0.1, 1.0, and 2.5 mg/m(3) of BaP absorbed onto carbon black particles using a state-of-the-art model aerosol generation system. Nominal and chamber concentrations of the particulate aerosol were determined gravimetrically with a seven-stage cascade impactor. The average aerosol for the 3 exposure concentrations used in this study exhibited a trimodal distribution with 93% cumulative mass less than 15.85 microm, 89% cumulative mass less than 10 microm, 55.3% cumulative mass less than 2.5 microm, and 38% less than 1 microm. Fifty-five percent of the aerosol had a cumulative mass less than PM(2.5) and the mass median aerodynamic diameter (MMAD) -/+ geometric standard deviation (GSD) for this mode was 1.7 -/+ 0.085 microm. Plasma and lung samples were collected at 30, 60, 120, and 240 min postexposure. The concentrations of BaP parent compound and metabolites were determined by high-performance liquid chromatography. The toxicokinetic parameters were computed from the time course of plasma BaP concentration. The bioavailability of BaP increased as a function of exposure concentration, and toxicokinetic analysis indicates first-order pharmacokinetics for BaP. However, some toxicokinetic parameters such as clearance and volume of distribution remained constant throughout the duration of the postexposure period. BaP and its metabolite concentrations in plasma peaked at 1 h postexposure. At 240 min postexposure, only trace levels of BaP remained in the plasma. The BaP metabolites in the lung showed an identical trend where no parent compound was detected. Among the metabolites detected, BaP 4,5-, 7,8-, and 9,10-dihydrodiols, 3-OH-BaP, and 9-OH-BaP were predominant.

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“…BPDE reacts readily with DNA to produce mutations, predominantly through base pair substitution at G:C [Carothers and Grunberger, 1990;Yang et al, 1991;Hennig et al, 1995]. Although BPDE is not a potent inducer of large deletions and insertions, it also causes loss of heterozygosity and chromosome breaks, and is known as strong clastogen [Lambert et al, 1994;Mazur-Melnyk et al, 1996;Wei et al, 1996]. Besides serving as a positive control for in vitro genotoxicity assays, BaP is positive in many in vivo assays, including the transgenic Big Blue assay and the in vivo micronucleus (MN) assay [Skopek et al, 1996;Bowen et al, 2011]; however, it has been challenging to detect BaP genotoxicity using the in vivo Comet assay [Bowen et al, 2011;Rothfuss et al, 2011].…”

Section: Introductionmentioning

confidence: 99%

Report on stage III Pig‐a mutation assays using benzo[a]pyrene

Bhalli

Shaddock

Pearce

et al. 2011

Environ and Mol Mutagen

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Genotoxicity assays were conducted on rats treated with benzo[a]pyrene (BaP) as part of Stage III of a validation study on the Pig-a gene mutation assay. Assays were performed at the U.S. FDA-NCTR and Bayer-Germany. Starting on Day 1, groups of five 6- to 7-week-old male Fischer 344 (F344, used at FDA-NCTR) and Han Wistar rats (Bayer) were given 28 daily doses of 0, 37.5, 75, or 150 mg/kg BaP; blood was sampled on Days -1, 4, 15, 29, and 56. Pig-a mutant frequencies were determined on Days -1, 15, 29, and 56 in total red blood cells (RBCs) and reticulocytes (RETs) as RBC(CD59-) and RET(CD59-) frequencies; percent micronucleated-RETs (%MN-RET) were measured on Days 4 and 29. RBC(CD59-) and RET(CD59-) frequencies increased in a dose- and time-dependent manner, producing significant increases by Day 29 in both rat models. The responses for RETs were stronger than those for RBCs, and the responses in F344 rats were stronger than in Han Wistar rats. BaP also produced significant increases in %MN-RET frequency at Days 4 and 29, with the responses being greater in F344 than Han Wistar rats. The overall findings were consistent with those of the reference laboratory using Han Wistar rats. Finally, mutation assays performed on splenocytes from Day 56 F344 rats indicated that BaP mutant frequencies were three to fivefold higher for the Hprt gene than the Pig-a gene. The results indicate that the Pig-a RET and RBC assays are reproducible, transferable, and show promise for integrating gene mutation into 28-day repeat-dose studies.

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Mutations induced in the hypoxanthine phosphoribosyl transferase gene by three urban air pollutants: acetaldehyde, benzo[a]pyrene diolepoxide, and ethylene oxide.

Cited by 11 publications

References 39 publications

Genomic assay reveals tolerance of DNA damage by both translesion DNA synthesis and homology-dependent repair in mammalian cells

Genomic assay reveals tolerance of DNA damage by both translesion DNA synthesis and homology-dependent repair in mammalian cells

TOXICOKINETICS OF INHALED BENZO[a]PYRENE: Plasma and Lung Bioavailability

Report on stage III Pig‐a mutation assays using benzo[a]pyrene

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