Nonhomologous end joining (NHEJ) is a major pathway for resolving chromosome double strand breaks. We have determined NHEJ's pivotal role in maintaining genome stability is at least in part due to a unique ability to cope with the complex broken end structures expected. We will address here if this is because NHEJ is adaptive - if it can sense differences in the type of damage, and tailor its path to resolution accordingly.
In Aim 1 we will address possible mechanisms for its unique ability to bypass the more subtle classes of damage at ends.
In Aim 2 we will address the role of three enzymes that are highly specific for removing different types of damage from ends. We will determine how end cleaning enzymes help define a next line of defense, to aid in resolving damaged ends when the damage cannot be bypassed.
In Aim 3 we will investigate the role of Artemis, a nuclease, which also removes damage from ends but which does not appear to be specific for a given type of damage. We will determine if Artemis defines the last line of defense, and helps remove damage at ends that could neither be bypassed nor cleaned. The effectiveness of some cancer therapies - radiation and certain chemotherapy agents - relies to a great degree on their ability to generate complex end structures that interfere with repair by NHEJ. Our studies will clarify the mechanism of resolving these ends, and how the mechanism can be manipulated to make therapies more effective and safer.

Public Health Relevance

Proposed work represents a systematic study addressing how human cells resolve chromosome breaks caused by exogenous damaging agents, with emphasis on those agents used for cancer therapy. Our results will provide insights into how such agents kills tumors, and will be used to generate safer and more effective methods for their use.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA084442-18
Application #
9414665
Study Section
Radiation Therapeutics and Biology Study Section (RTB)
Program Officer
Witkin, Keren L
Project Start
2000-01-04
Project End
2020-01-31
Budget Start
2018-02-01
Budget End
2019-01-31
Support Year
18
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Biochemistry
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Conlin, Michael P; Reid, Dylan A; Small, George W et al. (2017) DNA Ligase IV Guides End-Processing Choice during Nonhomologous End Joining. Cell Rep 20:2810-2819
Reid, Dylan A; Conlin, Michael P; Yin, Yandong et al. (2017) Bridging of double-stranded breaks by the nonhomologous end-joining ligation complex is modulated by DNA end chemistry. Nucleic Acids Res 45:1872-1878
Schellenberg, Matthew J; Perera, Lalith; Strom, Christina N et al. (2016) Reversal of DNA damage induced Topoisomerase 2 DNA-protein crosslinks by Tdp2. Nucleic Acids Res 44:3829-44
Almohaini, Mohammed; Chalasani, Sri Lakshmi; Bafail, Duaa et al. (2016) Nonhomologous end joining of complex DNA double-strand breaks with proximal thymine glycol and interplay with base excision repair. DNA Repair (Amst) 41:16-26
Reid, Dylan A; Keegan, Sarah; Leo-Macias, Alejandra et al. (2015) Organization and dynamics of the nonhomologous end-joining machinery during DNA double-strand break repair. Proc Natl Acad Sci U S A 112:E2575-84
Wilson, Justin E; Petrucelli, Alex S; Chen, Liang et al. (2015) Inflammasome-independent role of AIM2 in suppressing colon tumorigenesis via DNA-PK and Akt. Nat Med 21:906-13
Kusumoto-Matsuo, Rika; Ghosh, Deblina; Karmakar, Parimal et al. (2014) Serines 440 and 467 in the Werner syndrome protein are phosphorylated by DNA-PK and affects its dynamics in response to DNA double strand breaks. Aging (Albany NY) 6:70-81
Waters, Crystal A; Strande, Natasha T; Pryor, John M et al. (2014) The fidelity of the ligation step determines how ends are resolved during nonhomologous end joining. Nat Commun 5:4286
Strande, Natasha T; Carvajal-Garcia, Juan; Hallett, Ryan A et al. (2014) Requirements for 5'dRP/AP lyase activity in Ku. Nucleic Acids Res 42:11136-43
Waters, Crystal A; Strande, Natasha T; Wyatt, David W et al. (2014) Nonhomologous end joining: a good solution for bad ends. DNA Repair (Amst) 17:39-51

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