Exposure of cells to ionizing radiation and other carcinogenic agents induces DNA double-strand breaks (DSBs). Genetic studies in Saccharomyces cerevisiae and other organisms have revealed that homologous recombination (HR) and non-homologous DNA end joining (NHEJ) represent the major mechanisms for DSB elimination. During recombinational repair, ssDNA tails derived from break processing are bound by HR factors. The nucleoprotein complex thus formed conducts a search to locate an undamaged DNA homolog and catalyzes the formation of heteroduplex DNA joints with the homolog. The RAD50, RAD51, RAD52, RAD55, RAD57, RAD59, MRE11, and XRS2 genes are key members of the evolutionarily conserved RAD52 epistasis group that mediate mitotic and meiotic recombination and the recombinational repair of DSBs. The proteins encoded by MRE11, RAD50, and XRS2 are associated in a complex that plays roles in both HR and NHEJ. Rad51 protein, with the aid of ancillary factors, nucleates onto the ssDNA tails to form a nucleoprotein filament that has the ability to initiate heteroduplex DNA formation. In our renewal project, a combination of biochemical and genetic approaches will be used to (i) delineate the functions of MRE11/Rad50/Xrs2 in DSB repair, (ii) continue dissecting the mechanism of action of the Rad51-associated complex in heteroduplex DNA formation and chromatin remodeling, and (iii) define the multifaceted role of the Srs2 helicase in HR and DSB repair. Our studies will be important for deciphering the mechanism and functional significance of DSB repair in eukaryotes. Since defective DSB repair causes several human cancer-prone syndromes, the results from our project will be highly germane for understanding the biology and etiology of radiation-induced and chemical-induced carcinogenesis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES007061-16
Application #
7455083
Study Section
Cancer Etiology Study Section (CE)
Program Officer
Mcallister, Kimberly A
Project Start
1995-01-01
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2009-06-30
Support Year
16
Fiscal Year
2008
Total Cost
$360,827
Indirect Cost
Name
Yale University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Sung, Patrick (2018) Introduction to the Thematic Minireview Series: DNA double-strand break repair and pathway choice. J Biol Chem 293:10500-10501
Crickard, J Brooks; Kaniecki, Kyle; Kwon, YoungHo et al. (2018) Spontaneous self-segregation of Rad51 and Dmc1 DNA recombinases within mixed recombinase filaments. J Biol Chem 293:4191-4200
Crickard, J Brooks; Kaniecki, Kyle; Kwon, YoungHo et al. (2018) Regulation of Hed1 and Rad54 binding during maturation of the meiosis-specific presynaptic complex. EMBO J 37:
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
Crickard, J Brooks; Kaniecki, Kyle; Kwon, Youngho et al. (2018) Meiosis-specific recombinase Dmc1 is a potent inhibitor of the Srs2 antirecombinase. Proc Natl Acad Sci U S A 115:E10041-E10048
Rao, Timsi; Longerich, Simonne; Zhao, Weixing et al. (2018) Importance of homo-dimerization of Fanconi-associated nuclease 1 in DNA flap cleavage. DNA Repair (Amst) 64:53-58
Xu, Jingfei; Zhao, Lingyun; Xu, Yuanyuan et al. (2017) Cryo-EM structures of human RAD51 recombinase filaments during catalysis of DNA-strand exchange. Nat Struct Mol Biol 24:40-46
Kaniecki, Kyle; De Tullio, Luisina; Gibb, Bryan et al. (2017) Dissociation of Rad51 Presynaptic Complexes and Heteroduplex DNA Joints by Tandem Assemblies of Srs2. Cell Rep 21:3166-3177
Daley, James M; Jimenez-Sainz, Judit; Wang, Weibin et al. (2017) Enhancement of BLM-DNA2-Mediated Long-Range DNA End Resection by CtIP. Cell Rep 21:324-332
De Tullio, Luisina; Kaniecki, Kyle; Kwon, Youngho et al. (2017) Yeast Srs2 Helicase Promotes Redistribution of Single-Stranded DNA-Bound RPA and Rad52 in Homologous Recombination Regulation. Cell Rep 21:570-577

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