Errors in mitochondria! DNA replication have been hypothesized to drive aging and age-associated disease. The best evidence to date of a causal role for mitochondrial mutation in aging is the finding of an accelerated aging phenotype in mice expressing an error-prone form of the mitochondrial DNA polymerase; however, it is challenging to interpret data from studies performed with proteins having compromised function. Accordingly, I propose to develop a mitochondrial DNApolymerase with enhanced replication fidelity. An anti-mutator mitochondrial polymerase will serve as a model to determine the true role of mitochondrial DNA mutation in health and lifespan.
In Specific Aim 1, 1 will create specific mutations in the mouse mitochondrial DNA polymerase, utilizing known anti-mutator substitutions that have been characterized in prokaryotic model systems, and determine the effect of these substitutions on polymerase fidelity.
In Specific Aim 2, 1 will analyze the most promising anti-mutator polymerase mutants by quantitatively determining their activity, error rate, mutation spectrum, and biochemical properties.
In Specific Aim 3, 1 will determine the in vivo consequences of enhanced fidelity of mitochondrial DNA synthesis by expressing the anti-mutator polymerases in eukaryotic cells. A better understanding of the role of mitochondrial DNA replication fidelity in health and lifespan will lend insight into the fundamental mechanisms underlying aging itself. Because a large number of human diseases increase in both incidence and severity as a function of age, a better understanding of the aging process may result in strategies to delay or prevent the occurrence of disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Individual Predoctoral NRSA for M.D./Ph.D. Fellowships (ADAMHA) (F30)
Project #
5F30AG030314-03
Application #
7683004
Study Section
Special Emphasis Panel (ZRG1-F08-G (20))
Program Officer
Finkelstein, David B
Project Start
2007-11-23
Project End
2011-11-22
Budget Start
2009-11-23
Budget End
2010-11-22
Support Year
3
Fiscal Year
2009
Total Cost
$37,905
Indirect Cost
Name
University of Washington
Department
Pathology
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Schmitt, Michael W; Venkatesan, Ranga N; Pillaire, Marie-Jeanne et al. (2010) Active site mutations in mammalian DNA polymerase delta alter accuracy and replication fork progression. J Biol Chem 285:32264-72
Bielas, Jason H; Schmitt, Michael W; Icreverzi, Amalia et al. (2009) Molecularly evolved thymidylate synthase inhibits 5-fluorodeoxyuridine toxicity in human hematopoietic cells. Hum Gene Ther 20:1703-7
Schmitt, Michael W; Matsumoto, Yoshihiro; Loeb, Lawrence A (2009) High fidelity and lesion bypass capability of human DNA polymerase delta. Biochimie 91:1163-72