Genomic instabilities drive the progression of cancer, aging, and other human diseases. The integrity of our genome is especially at risk while it is being replicated, as replication forks often encounter obstacles to their progression, including DNA lesions, hard-to-replicate sequences, transcription intermediates, or protein-DNA complexes. These encounters often result in DNA breaks, gross chromosomal rearrangements and aneuploidy, which are key events in cancer initiation. The proper repair of stalled or collapsed replication forks through homologous recombination (HR)-based mechanisms plays a major role in preventing replication stress-induced genomic instabilities and many mutations in components of the HR machinery have been associated with cancer predisposition. In the absence of an intact HR-machinery, error-prone mechanisms such as non-homologous end joining (NHEJ) tend to become hyper-utilized, leading to extensive genomic instability. The regulatory basis of the recruitment of HR and NHEJ factors to DNA lesions is therefore of central interest to genome biology and cancer research, not only for explaining the mechanisms of tumorigenesis, but also for providing promising avenues for cancer therapy, as recently demonstrated for PARP inhibitors that are now approved for treatment of ovarian cancer patients with BRCA1 mutations in Europe and the US. This proposal will investigate a new mechanism for regulation of recombinational DNA repair and repair pathway choice. The central hypothesis is that the evolutionarily conserved scaffolding protein TopBP1 plays a central, yet largely unexplored, role in the control of HR-mediated repair and DNA repair pathway choice. Utilizing biochemical, proteomic and genetic approaches in yeast, human cell lines and genome-edited mice, we will define the molecular mechanism by which TopBP1 and its yeast ortholog Dpb11 control DNA repair. Our studies will provide unparalleled molecular understanding of how the action of key HR and NHEJ factors are coordinated and will reveal how signaling networks integrate the control of DNA replication, checkpoint signaling and DNA repair. Proposed experiments will reveal novel mechanisms of repair pathway choice and recombinational repair that are crucial to suppress genomic instability and cancer. Generated outcomes will have implications in the study of tumorigenesis caused by dysfunctions in HR repair and should provide new rationale for therapy.

Public Health Relevance

This proposal investigates how cells replicate their genome and how DNA damage occurring during the replication process is repaired. The generated knowledge will have direct implications to understand the mechanisms of tumorigenesis, especially in individuals with mutations in BRCA1, one of the most frequently mutated genes in hereditary breast and ovarian cancer. In addition, the knowledge generated from our studies will help in the design of better therapies that target specific DNA repair deficiencies in cancer cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM097272-09
Application #
9923716
Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Reddy, Michael K
Project Start
2011-09-01
Project End
2021-04-30
Budget Start
2020-05-01
Budget End
2021-04-30
Support Year
9
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Cornell University
Department
Miscellaneous
Type
Organized Research Units
DUNS #
872612445
City
Ithaca
State
NY
Country
United States
Zip Code
14850
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Lanz, Michael Charles; Oberly, Susannah; Sanford, Ethan James et al. (2018) Separable roles for Mec1/ATR in genome maintenance, DNA replication, and checkpoint signaling. Genes Dev 32:822-835
Bastos de Oliveira, Francisco M; Kim, Dongsung; Lanz, Michael et al. (2018) Quantitative Analysis of DNA Damage Signaling Responses to Chemical and Genetic Perturbations. Methods Mol Biol 1672:645-660
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Liu, Yi; Cussiol, José Renato; Dibitetto, Diego et al. (2017) TOPBP1Dpb11 plays a conserved role in homologous recombination DNA repair through the coordinated recruitment of 53BP1Rad9. J Cell Biol 216:623-639
Dibitetto, Diego; Ferrari, Matteo; Rawal, Chetan C et al. (2016) Slx4 and Rtt107 control checkpoint signalling and DNA resection at double-strand breaks. Nucleic Acids Res 44:669-82
Liu, Yi; Smolka, Marcus B (2016) TOPBP1 takes RADical command in recombinational DNA repair. J Cell Biol 212:263-6
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Zhou, Xiaolai; Sun, Lirong; Bastos de Oliveira, Francisco et al. (2015) Prosaposin facilitates sortilin-independent lysosomal trafficking of progranulin. J Cell Biol 210:991-1002
Balint, Attila; Kim, TaeHyung; Gallo, David et al. (2015) Assembly of Slx4 signaling complexes behind DNA replication forks. EMBO J 34:2182-97

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