DNA damage checkpoints coordinate the cellular responses to DNA damage caused by ionizing radiation and other genotoxic agents. The importance of DNA damage checkpoints for human cancer is exemplified by the cancer predisposition syndrome ataxia telangiectasia, in which a central checkpoint kinase is affected. DNA repair ensures cellular survival and genomic stability after DNA damage. Direct functional relationships between DNA damage checkpoints and DNA repair pathways have been postulated but are not well understood. The major genotoxic damage of ionizing radiation is DNA double-strand breaks. Homologous recombination is a ubiquitous, error-free DNA double-strand break repair pathway that functions also in the recovery of stalled replication forks. Aberrant processing of stalled forks is suspected to be a major source for genomic instability, a hallmark of cancer cells. How recombination is regulated is largely unknown. DNA damage-induced phosphorylation of Rad55-Rad57 is a novel checkpoint response that activates recombinational DNA repair. Rad55-Rad57 function in the assembly of the Rad51-ssDNA filament, which performs a central step during recombination but the exact mechanism is not defined. The goal is to establish mechanisms by which DNA damage checkpoints ensure survival and genomic stability after genotoxic stress. We focus on Rad55-Rad57 as a regulatory target to establish its mechanistic function and how phosphorylation enhances this function. The kinase control of Rad55-Rad57 phosphorylation suggests a potential positive feedback loop acting on the Mec1 (ATR) kinase. This hypothesis will be tested and the mechanisms involved elucidated. The evolutionary conservation of the major DNA damage checkpoint and DNA repair proteins suggests that yeast is a paradigmatic model system.
The specific aims are: (1) Establish the biological consequences of Rad55-Rad57 phosphorylation and determine the molecular mechanism of how phosphorylation affects protein stability. (2) Establish the in vivo molecular consequences of Rad55-Rad57 phosphorylation. (3) Determine the mechanism of action of Rad55-Rad57 and identify the mechanistic change imparted by phosphorylation. (4) Identify mechanisms of DNA damage checkpoint kinase regulation and test a positive feedback model involving Mec1 kinase.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA092276-06
Application #
7276721
Study Section
Cancer Etiology Study Section (CE)
Program Officer
Pelroy, Richard
Project Start
2001-07-01
Project End
2010-07-31
Budget Start
2007-08-01
Budget End
2008-07-31
Support Year
6
Fiscal Year
2007
Total Cost
$266,948
Indirect Cost
Name
University of California Davis
Department
Microbiology/Immun/Virology
Type
Schools of Arts and Sciences
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
Wright, William Douglass; Shah, Shanaya Shital; Heyer, Wolf-Dietrich (2018) Homologous recombination and the repair of DNA double-strand breaks. J Biol Chem 293:10524-10535
Piazza, Aurèle; Heyer, Wolf-Dietrich (2018) Multi-Invasion-Induced Rearrangements as a Pathway for Physiological and Pathological Recombination. Bioessays 40:e1700249
Piazza, Aurèle; Koszul, Romain; Heyer, Wolf-Dietrich (2018) A Proximity Ligation-Based Method for Quantitative Measurement of D-Loop Extension in S. cerevisiae. Methods Enzymol 601:27-44
Liu, Jie; Ede, Christopher; Wright, William D et al. (2017) Srs2 promotes synthesis-dependent strand annealing by disrupting DNA polymerase ?-extending D-loops. Elife 6:
Muñoz-Galván, Sandra; Tous, Cristina; Blanco, Miguel G et al. (2017) Correction for Muñoz-Galván et al., ""Distinct Roles of Mus81, Yen1, Slx1-Slx4, and Rad1 Nucleases in the Repair of Replication-Born Double-Strand Breaks by Sister Chromatid Exchange"". Mol Cell Biol 37:
Piazza, Aurèle; Wright, William Douglass; Heyer, Wolf-Dietrich (2017) Multi-invasions Are Recombination Byproducts that Induce Chromosomal Rearrangements. Cell 170:760-773.e15
Crawley, Jacqueline N; Heyer, Wolf-Dietrich; LaSalle, Janine M (2016) Autism and Cancer Share Risk Genes, Pathways, and Drug Targets. Trends Genet 32:139-146
McVey, Mitch; Khodaverdian, Varandt Y; Meyer, Damon et al. (2016) Eukaryotic DNA Polymerases in Homologous Recombination. Annu Rev Genet 50:393-421
Janke, Ryan; Kong, Jeremy; Braberg, Hannes et al. (2016) Nonsense-mediated decay regulates key components of homologous recombination. Nucleic Acids Res 44:5218-30
Heyer, Wolf-Dietrich (2015) Regulation of recombination and genomic maintenance. Cold Spring Harb Perspect Biol 7:a016501

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