The DNA damage checkpoint pathways exert multiple controls on the efficiency and outcome of the repair of a double-stranded DNA gap

Edwin Haghnazari, Wolf Dietrich Heyer

Research output: Contribution to journalArticle

18 Scopus citations


A DNA gap repair assay was used to determine the effect of mutations in the DNA damage checkpoint system on the efficiency and outcome (crossover/non-crossover) of recombinational DNA repair. In Saccharomyces cerevisiae gap repair is largely achieved by homologous recombination. As a result the plasmid either integrates into the chromosome (indicative of a crossover outcome) or remains extra-chromosomal (indicative of a non-crossover outcome). Deletion mutants of the MEC1 and RADS53 checkpoint kinase genes exhibited a 5-fold decrease in gap repair efficiency, showing that 80% of the gap repair events depended on functional DNA damage checkpoints. Epistasis analysis suggests that the DNA damage checkpoints affect gap repair by modulating Rad51 protein-mediated homologous recombination. While in wild-type cells only ∼25% of the gap repair events were associated with a crossover outcome, Mec1-deficient cells exhibited a >80% crossover association. Also mutations in the effector kinases Rad53, Chk1 and Dun1 were found to affect crossover association of DNA gap repair to various degrees. The data suggest that the DNA damage checkpoints are important for the optimal functioning of recombinational DNA repair with multiple terminal targets to modulate the efficiency and outcome of homologous recombination.

Original languageEnglish (US)
Pages (from-to)4257-4268
Number of pages12
JournalNucleic Acids Research
Issue number14
StatePublished - 2004


ASJC Scopus subject areas

  • Genetics

Cite this