Double-strand break repair: are Rad51/RecA--DNA joints barriers to DNA replication?
The central step of homologous recombination is the DNA strand exchange reaction catalyzed by bacterial RecA or eukaryotic Rad51. Besides Rad51-mediated synthesis-dependent strand annealing (SDSA), DNA ends can promote replication in Escherichia coli (recombination-dependent replication, RDR) and yeast (break-induced replication, BIR). However, what causes a DNA end to be repaired via SDSA or via BIR/RDR? I propose that Rad51/RecA--DNA plectonemic joints act as barriers to DNA replication and that BIR/RDR is only possible when the DNA polymerase that synthesizes DNA from the invading 3' end does not encounter RecA/Rad51--DNA joints in its path.
Aguilera
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Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avd. Reina Mercedes 6, 41012 Sevilla, Spain. aguilo@cica.es
D000818:Animals; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004249:DNA Damage; D004254:DNA Nucleotidyltransferases / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D051135:Rad51 Recombinase; D011938:Rec A Recombinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins
D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; D004254:DNA Nucleotidyltransferases; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase; D011938:Rec A Recombinases