OF WORK: Our studies of mammalian DNA polymerase beta have pioneered the use of a coordinated approach of structural studies (x-ray crystallography, NMR, and spectroscopy), biochemical studies, and mammalian genetic studies. This approach has allowed us to establish the cellular role(s) of DNA polymerase beta in mammalian base excision repair. And, the approach has allowed us to establish a solid framework for future studies of individual amino acid residues in this enzyme in such important endpoints as cellular response to genotoxicants, the rate of DNA repair, coordination of DNA repair with cellular checkpoint control and also with apoptosis signalling, coordination of deoxyribose phosphate removal (lyase activity) with DNA synthesis, the fidelity of DNA synthesis, the fidelity of overall DNA base excision repair, and DNA lesion bypass. Rational drug design, targeting one or more of these features will allow us to strategically regulate base excision repair with DNA polymerase beta specific drugs. Such agents will be useful in cancer chemotherapy and in helping us to better understand the role of DNA repair in oncogenesis and other chronic diseases. Detailed structure-function relationship studies of other base excision repair (BER) enzymes, such as FEN-1, PARP-1, XRCC1, DNA ligases I and III, AP endonuclease, and the various DNA glycosylases, will be undertaken in the future. Development of specific inhibitors or other modulators for these enzymes will allow us to strategically deregulate base excision repair in cells. This will have implications for chemotherapy and for understanding the role of DNA repair in preventing disease after exposure to environmental toxicants.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Intramural Research (Z01)
Project #
1Z01ES050158-06
Application #
6673020
Study Section
(LSB)
Project Start
Project End
Budget Start
Budget End
Support Year
6
Fiscal Year
2002
Total Cost
Indirect Cost
Name
U.S. National Inst of Environ Hlth Scis
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Horton, Julie K; Stefanick, Donna F; Ça?layan, Melike et al. (2018) XRCC1 phosphorylation affects aprataxin recruitment and DNA deadenylation activity. DNA Repair (Amst) 64:26-33
Ça?layan, Melike; Wilson, Samuel H (2018) Pol ? dGTP mismatch insertion opposite T coupled with ligation reveals promutagenic DNA repair intermediate. Nat Commun 9:4213
Oertell, Keriann; Kashemirov, Boris A; Negahbani, Amirsoheil et al. (2018) Probing DNA Base-Dependent Leaving Group Kinetic Effects on the DNA Polymerase Transition State. Biochemistry 57:3925-3933
Çaglayan, Melike; Wilson, Samuel H (2017) Role of DNA polymerase ? oxidized nucleotide insertion in DNA ligation failure. J Radiat Res 58:603-607
Ça?layan, Melike; Horton, Julie K; Dai, Da-Peng et al. (2017) Oxidized nucleotide insertion by pol ? confounds ligation during base excision repair. Nat Commun 8:14045
Shock, David D; Freudenthal, Bret D; Beard, William A et al. (2017) Modulating the DNA polymerase ? reaction equilibrium to dissect the reverse reaction. Nat Chem Biol 13:1074-1080
Horton, Julie K; Stefanick, Donna F; Zhao, Ming-Lang et al. (2017) XRCC1-mediated repair of strand breaks independent of PNKP binding. DNA Repair (Amst) 60:52-63
Prasad, Rajendra; Ça?layan, Melike; Dai, Da-Peng et al. (2017) DNA polymerase ?: A missing link of the base excision repair machinery in mammalian mitochondria. DNA Repair (Amst) 60:77-88
Howard, Michael J; Wilson, Samuel H (2017) Processive searching ability varies among members of the gap-filling DNA polymerase X family. J Biol Chem 292:17473-17481
Kirby, Thomas W; Gassman, Natalie R; Smith, Cassandra E et al. (2017) DNA polymerase ? contains a functional nuclear localization signal at its N-terminus. Nucleic Acids Res 45:1958-1970

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