Carcinogenesis involves multiple genetic changes that result from errors in repair of DNA damage. Several highly error prone mechanisms for repair of DNA breaks exist which can serve as the source of mutations and drive formation and/or maintenance of a variety of cancers. It is thus of significant public health interest to define how and when cells rely on error prone mechanisms to repair DNA breaks and assess cellular and pathological consequences of genetic alterations associated with these processes. The goal of this proposal is to elucidate the molecular mechanisms of one of these error prone repair mechanisms of DNA breaks in eukaryotes and the newly identified recombination proteins crucial for such recombination reaction. Recombination between tandem repeat sequences is an evolutionary conserved error prone mechanism that repairs DNA breaks by producing sequence deletions. To define genetic component of this recombination process, we screened genes needed for efficient repair of breaks flanking direct repeats with an approach that combines yeast genetics and microarray technology. This screen uncovered two new recombination genes, SLX4 and SAW1, that function in removal of 3'flaps from recombination intermediates. Removal of a 3'flap also depends on the structure specific endonuclease complex, Rad1/Rad10, and dictates cellular tolerance to cancer chemotherapeutic agents, gene targeting, telomere integrity, repair of oxidative damage and suppression of aging. To decipher biochemical and molecular basis of error prone recombination, we plan to define the biochemical properties of Saw1 in recombination and recombination related biological processes including repair of DNA lesions blocking ongoing replication fork progression. We will reconstitute the 3'flap removal process during recombination using purified recombination proteins and a 3'flap DNA. The information will help devise clinical strategies to reduce or eliminate mutagenic repair germane to carcinogenesis and pave the way for improved cancer therapeutics.

Public Health Relevance

The purpose of this application is to decipher molecular inner-workings of error prone mechanism for repairing DNA breaks that results in genetic changes pertinent to carcinogenesis. The information gleaned from the proposal will also provide a logical framework as to how cells tolerate cancer therapeutic agent-induced DNA lesions and shed lights on the prevention and improved therapeutic intervention of cancers.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM071011-08
Application #
8245893
Study Section
Cancer Genetics Study Section (CG)
Program Officer
Janes, Daniel E
Project Start
2004-04-01
Project End
2014-07-31
Budget Start
2012-04-01
Budget End
2014-07-31
Support Year
8
Fiscal Year
2012
Total Cost
$261,981
Indirect Cost
$85,563
Name
University of Texas Health Science Center San Antonio
Department
Other Basic Sciences
Type
Schools of Medicine
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
Wang, Weibin; Daley, James M; Kwon, Youngho et al. (2018) A DNA nick at Ku-blocked double-strand break ends serves as an entry site for exonuclease 1 (Exo1) or Sgs1-Dna2 in long-range DNA end resection. J Biol Chem 293:17061-17069
Eichmiller, Robin; Medina-Rivera, Melisa; DeSanto, Rachel et al. (2018) Coordination of Rad1-Rad10 interactions with Msh2-Msh3, Saw1 and RPA is essential for functional 3' non-homologous tail removal. Nucleic Acids Res 46:5075-5096
Obeidat, Mohammad; McConnell, Kristen A; Li, Xiaolei et al. (2018) DNA double-strand breaks as a method of radiation measurements for therapeutic beams. Med Phys 45:3460-3465
Seol, Ja-Hwan; Holland, Cory; Li, Xiaolei et al. (2018) Distinct roles of XPF-ERCC1 and Rad1-Rad10-Saw1 in replication-coupled and uncoupled inter-strand crosslink repair. Nat Commun 9:2025
Liu, Yaqi; Sung, Sihyun; Kim, Youngran et al. (2016) ATP-dependent DNA binding, unwinding, and resection by the Mre11/Rad50 complex. EMBO J 35:743-58
Sinha, Supriya; Villarreal, Diana; Shim, Eun Yong et al. (2016) Risky business: Microhomology-mediated end joining. Mutat Res 788:17-24
Che, Jun; Smith, Stephanie; Kim, Yoo Jung et al. (2015) Hyper-Acetylation of Histone H3K56 Limits Break-Induced Replication by Inhibiting Extensive Repair Synthesis. PLoS Genet 11:e1004990
Sung, Sihyun; Li, Fuyang; Park, Young Bong et al. (2014) DNA end recognition by the Mre11 nuclease dimer: insights into resection and repair of damaged DNA. EMBO J 33:2422-35
Sarangi, Prabha; Altmannova, Veronika; Holland, Cory et al. (2014) A versatile scaffold contributes to damage survival via sumoylation and nuclease interactions. Cell Rep 9:143-152
Sarangi, Prabha; Bartosova, Zdenka; Altmannova, Veronika et al. (2014) Sumoylation of the Rad1 nuclease promotes DNA repair and regulates its DNA association. Nucleic Acids Res 42:6393-404

Showing the most recent 10 out of 23 publications