Open AccessRAD51 Is Required for the Repair of Plasmid Double-Stranded DNA Gaps from Either Plasmid or Chromosomal Templates
Author(s) -
Stephan Bärtsch,
Leslie E. Kang,
Lorraine S. Symington
Publication year - 2000
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.20.4.1194-1205.2000
Subject(s) - rad52 , rad51 , homologous recombination , biology , homology directed repair , plasmid , non homologous end joining , dna repair , genetics , replication protein a , dna repair protein xrcc4 , ectopic recombination , dna , microbiology and biotechnology , gene , genetic recombination , recombination , nucleotide excision repair , dna binding protein , transcription factor
DNA double-strand breaks may be induced by endonucleases, ionizing radiation, chemical agents, and mechanical forces or by replication of single-stranded nicked chromosomes. Repair of double-strand breaks can occur by homologous recombination or by nonhomologous end joining. A system was developed to measure the efficiency of plasmid gap repair by homologous recombination using either chromosomal or plasmid templates. Gap repair was biased toward gene conversion events unassociated with crossing over using either donor sequence. The dependence of recombinational gap repair on genes belonging to theRAD52 epistasis group was tested in this system.RAD51 ,RAD52 ,RAD57 , andRAD59 were required for efficient gap repair using either chromosomal or plasmid donors. No homologous recombination products were recovered fromrad52 mutants, whereas a low level of repair occurred in the absence ofRAD51 ,RAD57 , orRAD59 . These results suggest a minor pathway of strand invasion that is dependent onRAD52 but not onRAD51 . The residual repair events inrad51 mutants were more frequently associated with crossing over than was observed in the wild-type strain, suggesting that the mechanisms forRAD51 -dependent andRAD51 -independent events are different. Plasmid gap repair was reduced synergistically inrad51 rad59 double mutants, indicating an important role forRAD59 inRAD51 -independent repair.