SbcCD causes a double-strand break at a DNA palindrome in the Escherichia coli chromosome.
Long DNA palindromes are sites of genome instability (deletions, amplification, and translocations) in both prokaryotic and eukaryotic cells. In Escherichia coli, genetic evidence has suggested that they are sites of DNA cleavage by the SbcCD complex that can be repaired by homologous recombination. Here we obtain in vivo physical evidence of an SbcCD-induced DNA double-strand break (DSB) at a palindromic sequence in the E. coli chromosome and show that both ends of the break stimulate recombination. Cleavage is dependent on DNA replication, but the observation of two ends at the break argues that cleavage does not occur at the replication fork. Genetic analysis shows repair of the break requires the RecBCD recombination pathway and PriA, suggesting a mechanism of bacterial DNA DSB repair involving the establishment of replication forks.
Eykelenboom
John K
JK
Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK.
Blackwood
John K
JK
Okely
Ewa
E
Leach
David R F
DR
D001483:Base Sequence; D002876:Chromosomes, Bacterial; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004260:DNA Repair; D003851:Deoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D043211:Exodeoxyribonuclease V / Q000378:metabolism; D005092:Exonucleases / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic
D029968:Escherichia coli Proteins; C489229:SbcC protein, E coli; D003851:Deoxyribonucleases; D005092:Exonucleases; C081229:sbcD protein, E coli; D043211:Exodeoxyribonuclease V