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.
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.
|Crawley, Jacqueline N; Heyer, Wolf-Dietrich; LaSalle, Janine M (2016) Autism and Cancer Share Risk Genes, Pathways, and Drug Targets. Trends Genet 32:139-46|
|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|
|Fasching, Clare L; Cejka, Petr; Kowalczykowski, Stephen C et al. (2015) Top3-Rmi1 dissolve Rad51-mediated D loops by a topoisomerase-based mechanism. Mol Cell 57:595-606|
|Mukherjee, Sucheta; Wright, William Douglass; Ehmsen, Kirk Tevebaugh et al. (2014) The Mus81-Mms4 structure-selective endonuclease requires nicked DNA junctions to undergo conformational changes and bend its DNA substrates for cleavage. Nucleic Acids Res 42:6511-22|
|Wright, William Douglass; Heyer, Wolf-Dietrich (2014) Rad54 functions as a heteroduplex DNA pump modulated by its DNA substrates and Rad51 during D loop formation. Mol Cell 53:420-32|
|Zinovyev, Andrei; Kuperstein, Inna; Barillot, Emmanuel et al. (2013) Synthetic lethality between gene defects affecting a single non-essential molecular pathway with reversible steps. PLoS Comput Biol 9:e1003016|
|Zhang, Xiao-Ping; Heyer, Wolf-Dietrich (2011) Quality control of purified proteins involved in homologous recombination. Methods Mol Biol 745:329-43|
|Liu, Jie; Ehmsen, Kirk T; Heyer, Wolf-Dietrich et al. (2011) Presynaptic filament dynamics in homologous recombination and DNA repair. Crit Rev Biochem Mol Biol 46:240-70|
|Schwartz, Erin K; Heyer, Wolf-Dietrich (2011) Processing of joint molecule intermediates by structure-selective endonucleases during homologous recombination in eukaryotes. Chromosoma 120:109-27|
Showing the most recent 10 out of 27 publications