The DNA damage response (DDR) ensures genomic stability and survival under genotoxic stress conditions. One of the DDR effector pathways is homologous recombination, a DNA repair option that addresses DNA double-stranded breaks and other complex DNA damage such as interstrand crosslinks. Induction of such types of DNA damage constitutes the functional principle of a large number of cancer treatment modalities, highlighting the importance to understand the underlying biological processes. A long-term goal is to identify the mechanism of recombinational DNA repair and how they are regulated by the DDR. Specifically, we focus on the mechanism and regulation of the assembly of the Rad51-ssDNA filament, a key intermediate in recombinational repair. Another goal is to identify negative and positive control mechanisms that govern DDR signaling and how they affect cell cycle phase-specific regulation. Defects in the DDR and recombinational repair predispose individuals to cancer, providing significant impetus to understand the basic biological mechanisms involved.
The Specific Aims are: (1) Determine the mechanisms of Rad51-ssDNA filament assembly. The presynaptic Rad51-ssDNA filament exists in a meta-stable balance between its assembly and disassembly. We will test mechanistic models, how the Rad51 paralogs Rad55-Rad57 antagonize the anti-recombination function of Srs2. (2) Regulation of Rad51-ssDNA filament assembly by post-translational modification. Genetic experiments are leading biochemical approaches to examine the effect of post-translational modifications of Rad55-Rad57, Srs2 and PCNA on Rad51-ssDNA filament assembly/disassembly. Genetic and biochemical approaches will identify modification-specific interaction partners of Rad55-Rad57. (3) Determine mechanisms of the G1 DNA damage response. The G1-S border is a major regulatory transition in the mammalian DNA damage response but understudied in yeast. We will identify mechanisms in G1 checkpoint control involving negative control on Mec1 kinase in haploid and diploid yeast cells. (4) Determine the mechanism of positive feedback regulation of Mec1 kinase. While the initial activation of Mec1 kinase is understood to some detail, the mechanisms involved in the maintenance of its activated state remain unclear. We will combine biochemical and genetic approaches to determine the mechanism of positive feedback regulation on Mec1 kinase.

Public Health Relevance

The DNA damage response maintains genomic stability and ensures survival by coordinating key effector pathways such as homologous recombination, a major DNA repair pathway for DNA double-stranded breaks and other types of complex DNA damage. Such DNA lesions are induced by ionizing radiation and other modalities in cancer treatment. The work in this proposal will lead to an improved mechanistic understanding of the DNA damage response and homologous recombination, which is fundamental in using biological approaches to improve the efficacy and reduce the side-effects of DNA damage-based anti-tumor therapy.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA092276-13
Application #
8678853
Study Section
Cancer Etiology Study Section (CE)
Program Officer
Pelroy, Richard
Project Start
2001-07-01
Project End
2015-06-30
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
13
Fiscal Year
2014
Total Cost
$260,105
Indirect Cost
$84,363
Name
University of California Davis
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
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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