Robust cellular repair pathways maintain genomic integrity by eliminating or reducing genetic alterations following DMA damage. In the absence or malfunction of such pathways, health is compromised and individuals can be cancer-prone. Double-strand breaks (DSBs) are a particularly injurious type of DMA damage. DSBs occur spontaneously in chromosomes as a result of normal DMA metabolism and after exposure to exogenous DNA damaging agents, such as ionizing radiation. We have demonstrated that a major pathway involved in DSB repair is homologous recombination (HR). In HR, an undamaged homologous sequence templates the repair of the broken chromosome, making it a precise type of repair. The proposed research focuses on understanding the factors that promote HR in mammalian cells and the consequences of impaired HR on organismal health.
Specific aim 1 is a structure-function analysis of the tumor suppressor BRCA2 and its role in promoting cell survival, HR, and organismal viability in the mouse. There is a specific emphasis on the role of various subdomains of the BRCA2 DNA binding domain. In addition, the role of several patient mutations will be investigated.
In specific aim 2 the cellular requirements for HR correction in Brca2 and other HR mutant cells will be investigated. Our preliminary analysis indicates that the function of BRCA2 in HR is to deliver the Rad51 strand exchange protein to single-stranded DNA. Experiments are proposed to test and extend this hypothesis are proposed.
Specific aim 3 is to investigate the dependence on HR factors in the mouse. Mice with severe HR deficiency die early in embryogenesis, although mice with less severe deficiencies progress further in development or are viable. To understand the dependencies and uncover roles for HR factors in the mouse, we will analyze mice that carry mutations in combinations of HR factors. The roles of a gene encoding a Rad51 paralog (Xrcc2) and other Rad52 epistasis group members (Rad52 and Rad54) will be investigated, as well as that of a hypomorphic Brca2 allele.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
3R01GM054668-12S1
Application #
7989704
Study Section
Radiation Therapeutics and Biology Study Section (RTB)
Program Officer
Hagan, Ann A
Project Start
2009-12-17
Project End
2010-12-31
Budget Start
2009-12-17
Budget End
2010-12-31
Support Year
12
Fiscal Year
2010
Total Cost
$208,314
Indirect Cost
Name
Sloan-Kettering Institute for Cancer Research
Department
Type
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10065
Vriend, Lianne E M; Prakash, Rohit; Chen, Chun-Chin et al. (2016) Distinct genetic control of homologous recombination repair of Cas9-induced double-strand breaks, nicks and paired nicks. Nucleic Acids Res 44:5204-17
Browning, Cynthia L; Qin, Qin; Kelly, Deborah F et al. (2016) Prolonged Particulate Hexavalent Chromium Exposure Suppresses Homologous Recombination Repair in Human Lung Cells. Toxicol Sci 153:70-8
Jasin, Maria; Haber, James E (2016) The democratization of gene editing: Insights from site-specific cleavage and double-strand break repair. DNA Repair (Amst) 44:6-16
Prakash, Rohit; Zhang, Yu; Feng, Weiran et al. (2015) Homologous recombination and human health: the roles of BRCA1, BRCA2, and associated proteins. Cold Spring Harb Perspect Biol 7:a016600
Goglia, Alexander G; Delsite, Robert; Luz, Antonio N et al. (2015) Identification of novel radiosensitizers in a high-throughput, cell-based screen for DSB repair inhibitors. Mol Cancer Ther 14:326-42
Vriend, Lianne E M; Jasin, Maria; Krawczyk, Przemek M (2014) Assaying break and nick-induced homologous recombination in mammalian cells using the DR-GFP reporter and Cas9 nucleases. Methods Enzymol 546:175-91
Renouf, Benjamin; Piganeau, Marion; Ghezraoui, Hind et al. (2014) Creating cancer translocations in human cells using Cas9 DSBs and nCas9 paired nicks. Methods Enzymol 546:251-71
Zhang, Yu; Vanoli, Fabio; LaRocque, Jeannine R et al. (2014) Biallelic targeting of expressed genes in mouse embryonic stem cells using the Cas9 system. Methods 69:171-178
Ghezraoui, Hind; Piganeau, Marion; Renouf, Benjamin et al. (2014) Chromosomal translocations in human cells are generated by canonical nonhomologous end-joining. Mol Cell 55:829-842
Jasin, Maria; Rothstein, Rodney (2013) Repair of strand breaks by homologous recombination. Cold Spring Harb Perspect Biol 5:a012740

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