of Work: In humans and other eukaryotes the repair of DSBs is dependent upon proteins involved in chromatin structure, cell cycle response mechanisms and the enzymatic rejoining of broken DNA ends. Mutations within genes involved in break repair and in cell cycle responses to DNA strand breaks have been shown to be responsible for several human cancers and have also been implicated in the aging process. Our research efforts have focused on DSB repair in the genetically tractable yeast Saccharomyces cerevisiae. Many genes involved in DNA repair are conserved between humans and yeast. We have investigated several important aspects of DSB repair. These include i) analysis of the relative contributions of recombinational repair versus non- recombinational end-joining; ii) characterization of damage-responsive cell cycle checkpoints and identification of genes participating in these processes; iii) investigation of repair pathways available for DSBs which have alternative structures at the ends, i.e. blunt, complementary, modified, or damaged termini; and iv) systematic analysis of genes involved in the enzymatic repair of DNA strand breaks. Conclusions of this work include the following: all DSBs can be repaired by recombination mediated by the RAD52 group of DNA repair genes. Only DSBs with complementary ends are substrates for end-joining, which requires yKU70, yKU80 and RAD50. All forms of DSBs induce G2-phase arrest and this process is dependent upon RAD9 and RAD17. Genes involved in post- replication repair, including RAD5 and RAD6, are also required for DSB repair. All types of DSBs tested induce recombination and aneuploidy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Intramural Research (Z01)
Project #
1Z01ES021016-16
Application #
6162087
Study Section
Special Emphasis Panel (LMG)
Project Start
Project End
Budget Start
Budget End
Support Year
16
Fiscal Year
1997
Total Cost
Indirect Cost
City
State
Country
United States
Zip Code
Andres, Sara N; Appel, C Denise; Westmoreland, James W et al. (2015) Tetrameric Ctp1 coordinates DNA binding and DNA bridging in DNA double-strand-break repair. Nat Struct Mol Biol 22:158-66
Ma, Wenjian; Westmoreland, Jim W; Gordenin, Dmitry A et al. (2011) Alkylation base damage is converted into repairable double-strand breaks and complex intermediates in G2 cells lacking AP endonuclease. PLoS Genet 7:e1002059
Nakai, Wataru; Westmoreland, Jim; Yeh, Elaine et al. (2011) Chromosome integrity at a double-strand break requires exonuclease 1 and MRX. DNA Repair (Amst) 10:102-10
Argueso, Juan Lucas; Westmoreland, James; Mieczkowski, Piotr A et al. (2008) Double-strand breaks associated with repetitive DNA can reshape the genome. Proc Natl Acad Sci U S A 105:11845-50
Lewis, L Kevin; Lobachev, Kirill; Westmoreland, James W et al. (2005) Use of a restriction endonuclease cytotoxicity assay to identify inducible GAL1 promoter variants with reduced basal activity. Gene 363:183-92
Chen, Ling; Trujillo, Kelly M; Van Komen, Stephen et al. (2005) Effect of amino acid substitutions in the rad50 ATP binding domain on DNA double strand break repair in yeast. J Biol Chem 280:2620-7
Resnick, Michael A (2005) Reduced replication: a call to ARMS. Cell 120:569-70
Lewis, L Kevin; Karthikeyan, G; Cassiano, Jared et al. (2005) Reduction of nucleosome assembly during new DNA synthesis impairs both major pathways of double-strand break repair. Nucleic Acids Res 33:4928-39
Lewis, L Kevin; Storici, Francesca; Van Komen, Stephen et al. (2004) Role of the nuclease activity of Saccharomyces cerevisiae Mre11 in repair of DNA double-strand breaks in mitotic cells. Genetics 166:1701-13
Lobachev, Kirill; Vitriol, Eric; Stemple, Jennifer et al. (2004) Chromosome fragmentation after induction of a double-strand break is an active process prevented by the RMX repair complex. Curr Biol 14:2107-12

Showing the most recent 10 out of 11 publications