RAD51-dependent break-induced replication differs in kinetics and checkpoint responses from RAD51-mediated gene conversion.
Diploid Saccharomyces cells experiencing a double-strand break (DSB) on one homologous chromosome repair the break by RAD51-mediated gene conversion >98% of the time. However, when extensive homologous sequences are restricted to one side of the DSB, repair can occur by both RAD51-dependent and RAD51-independent break-induced replication (BIR) mechanisms. Here we characterize the kinetics and checkpoint dependence of RAD51-dependent BIR when the DSB is created within a chromosome. Gene conversion products appear within 2 h, and there is little, if any, induction of the DNA damage checkpoint; however, RAD51-dependent BIR occurs with a further delay of 2 to 4 h and cells arrest in response to the G(2)/M DNA damage checkpoint. RAD51-dependent BIR does not require special facilitating sequences that are required for a less efficient RAD51-independent process. RAD51-dependent BIR occurs efficiently in G(2)-arrested cells. Once repair is initiated, the rate of repair replication during BIR is comparable to that of normal DNA replication, as copying of >100 kb is completed less than 30 min after repair DNA synthesis is detected close to the DSB.
Malkova
Anna
A
Rosenstiel Center, Brandeis University, 415 South St., Mail Stop 029, Waltham, MA 02454-9110, USA.
Naylor
Maria L
ML
Yamaguchi
Miyuki
M
Ira
Grzegorz
G
Haber
James E
JE
D002453:Cell Cycle / Q000235:genetics; D015825:Chromosomes, Fungal / Q000235:genetics; D004260:DNA Repair / Q000235:genetics*; D004261:DNA Replication / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005785:Gene Conversion; D018816:Genes, cdc; D051135:Rad51 Recombinase; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
D004268:DNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase