The broad long-term objective of the proposed research is to further our understanding of the molecular mechanisms used by DNA polymerase beta to catalyze the accurate synthesis of DNA.
The Specific Aims are to determine if amino acid residues that are critical for fidelity of DNA polymerase Beta re located throughout the protein, to understand the molecular basis of infidelity of polymerase Beta mutator mutants, and to characterize the Pol Beta mutator mutants in vivo. DNA polymerase Beta has a central function in BER, which is a key repair pathway that is responsible for removing up to 10,000 DNA lesions per cell per day. Pol Beta also functions in meiosis. If an error is committed by Pol Beta during either of these processes, it has the potential to result in a mutation that can ultimately lead to human disease. Pol Beta has been implicated carcinogenesis by the demonstration that the Pol Beta locus is mutated in human colon and human prostate carcinomas; one of the mutations results in a protein that has a dominant negative effect on BER in mammalian cells. Therefore, results of mechanistic studies of Pol B will further our understanding of the molecular basis of mutation and have the potential to contribute directly to our understanding of the etiology of significant human diseases, including cancer. Our approach includes identifying and characterizing DNA polymerase Beta mutants using a genetic screen we developed, and analyzing these mutants biochemically and structurally. We also will characterize the phenotypes of polymerase Beta mutants in vivo.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA080830-02
Application #
6150372
Study Section
Chemical Pathology Study Section (CPA)
Program Officer
Okano, Paul
Project Start
1999-04-07
Project End
2004-01-31
Budget Start
2000-02-01
Budget End
2001-01-31
Support Year
2
Fiscal Year
2000
Total Cost
$282,062
Indirect Cost
Name
Yale University
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
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Liptak, Cary; Mahmoud, Mariam M; Eckenroth, Brian E et al. (2018) I260Q DNA polymerase ? highlights precatalytic conformational rearrangements critical for fidelity. Nucleic Acids Res 46:10740-10756
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Eckenroth, Brian E; Towle-Weicksel, Jamie B; Nemec, Antonia A et al. (2017) Remote Mutations Induce Functional Changes in Active Site Residues of Human DNA Polymerase ?. Biochemistry 56:2363-2371
Alnajjar, Khadijeh S; Garcia-Barboza, Beatriz; Negahbani, Amirsoheil et al. (2017) A Change in the Rate-Determining Step of Polymerization by the K289M DNA Polymerase ? Cancer-Associated Variant. Biochemistry 56:2096-2105
Alnajjar, Khadijeh S; Negahbani, Amirsoheil; Nakhjiri, Maryam et al. (2017) DNA Polymerase ? Cancer-Associated Variant I260M Exhibits Nonspecific Selectivity toward the ?-? Bridging Group of the Incoming dNTP. Biochemistry 56:5449-5456
Mahmoud, Mariam M; Schechter, Allison; Alnajjar, Khadijeh S et al. (2017) Defective Nucleotide Release by DNA Polymerase ? Mutator Variant E288K Is the Basis of Its Low Fidelity. Biochemistry 56:5550-5559
Sohl, Christal D; Ray, Sreerupa; Sweasy, Joann B (2015) Pools and Pols: Mechanism of a mutator phenotype. Proc Natl Acad Sci U S A 112:5864-5
Towle-Weicksel, Jamie B; Dalal, Shibani; Sohl, Christal D et al. (2014) Fluorescence resonance energy transfer studies of DNA polymerase ?: the critical role of fingers domain movements and a novel non-covalent step during nucleotide selection. J Biol Chem 289:16541-50
Eckenroth, Brian E; Fleming, Aaron M; Sweasy, Joann B et al. (2014) Crystal structure of DNA polymerase ? with DNA containing the base lesion spiroiminodihydantoin in a templating position. Biochemistry 53:2075-7

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