The goal of this application is to investigate the mechanism by which nitroaromatic carcinogens cause mutations. We shall focus on the major DNA adducts formed by the nitropyrenes, the primary mutagenic pollutants in diesel exhaust, but also plan to initiate work on the DNA adducts of 3-nitrobenzanthrone, a recently discovered potent mutagenic and carcinogenic contaminant in diesel. We hypothesize that a group of DNA adducts formed by these nitroarenes play important roles in the etiology of human cancer via the mutagenic effects in crucial sequences of cancer genes (e.g., p53). We also hypothesize that most of these mutations occur via error-prone bypass of the lesions by Y-family DNA polymerases. In order to test these hypotheses, we shall synthesize and characterize oligonucleotides containing the major guanine adducts of 1-nitropyene, 1,6- and 1,8-dinitropyere, and 3-nitrobenzanthrone in important gene sequences. These adduct-containing oligonucleotides will be used to construct single-stranded plasmid or viral vectors and mutagenicity and genotoxicity will be evaluated in Escherichia coli and mammalian cells. The effect of specific repair or replication proteins will be assessed by using repair-proficient and -deficient cell lines or inhibitors. The cellular studies will be complemented by investigating in vitro kinetics and fidelity of polymerization catalyzed by Dpo4 and four human Y- family DNA polymerases. Initially, we shall focus on the C8 guanine adduct of 1-nitropyrene. The translesion synthesis products will be sequenced to determine the mutagenic pattern caused by each DNA polymerase. Finally, duplex plasmid vectors with these adducts will be constructed, and progression of replication fork will be examined in human cell extracts to determine if each adduct is significant block to fork progression. Mutational types and frequencies in double-stranded DNA will be determined. Together, these studies will provide a deeper understanding of the mechanism of mutagenesis induced by the DNA adducts of these nitroaromatic carcinogens.
Nitroaromatic compounds have been detected in a variety of environmental samples, including diesel exhaust. These compounds are potent mutagens and carcinogens, and it has been suggested that some of these pollutants play a role in human lung and breast cancer. Therefore, investigation of the mechanism by which the nitroaromatic carcinogens cause mutations has high significance to public health.
|Gadkari, Varun V; Tokarsky, E John; Malik, Chanchal K et al. (2014) Mechanistic investigation of the bypass of a bulky aromatic DNA adduct catalyzed by a Y-family DNA polymerase. DNA Repair (Amst) 21:65-77|
|Pednekar, Varsha; Weerasooriya, Savithri; Jasti, Vijay P et al. (2014) Mutagenicity and genotoxicity of (5'S)-8,5'-cyclo-2'-deoxyadenosine in Escherichia coli and replication of (5'S)-8,5'-cyclopurine-2'-deoxynucleosides in vitro by DNA polymerase IV, exo-free Klenow fragment, and Dpo4. Chem Res Toxicol 27:200-10|
|Kirouac, Kevin N; Basu, Ashis K; Ling, Hong (2013) Structural mechanism of replication stalling on a bulky amino-polycyclic aromatic hydrocarbon DNA adduct by a y family DNA polymerase. J Mol Biol 425:4167-76|
|Colis, Laureen C; Chakraborti, Debasis; Hilario, Pablo et al. (2009) Synthesis of oligonucleotides containing 2'-deoxyguanosine adducts of nitropyrenes. Nucleosides Nucleotides Nucleic Acids 28:67-77|
|Tolentino, Joel H; Burke, Tom J; Mukhopadhyay, Suparna et al. (2008) Inhibition of DNA replication fork progression and mutagenic potential of 1, N6-ethenoadenine and 8-oxoguanine in human cell extracts. Nucleic Acids Res 36:1300-8|
|Watt, Danielle L; Utzat, Christopher D; Hilario, Pablo et al. (2007) Mutagenicity of the 1-nitropyrene-DNA adduct N-(deoxyguanosin-8-yl)-1-aminopyrene in mammalian cells. Chem Res Toxicol 20:1658-64|
|Kalam, M Abul; Haraguchi, Kazuhiro; Chandani, Sushil et al. (2006) Genetic effects of oxidative DNA damages: comparative mutagenesis of the imidazole ring-opened formamidopyrimidines (Fapy lesions) and 8-oxo-purines in simian kidney cells. Nucleic Acids Res 34:2305-15|
|Ocampo-Hafalla, Maria T; Altamirano, Alvin; Basu, Ashis K et al. (2006) Repair of thymine glycol by hNth1 and hNeil1 is modulated by base pairing and cis-trans epimerization. DNA Repair (Amst) 5:444-54|
|Yang, Zhengguan; Roginskaya, Marina; Colis, Laureen C et al. (2006) Specific and efficient binding of xeroderma pigmentosum complementation group A to double-strand/single-strand DNA junctions with 3'- and/or 5'-ssDNA branches. Biochemistry 45:15921-30|
|Liu, Yu; Liu, Yiyong; Yang, Zhengguan et al. (2005) Cooperative interaction of human XPA stabilizes and enhances specific binding of XPA to DNA damage. Biochemistry 44:7361-8|
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