Single-strand interruptions in replicating chromosomes cause double-strand breaks
Abstract
Replication-dependent chromosomal breakage suggests that replication forks occasionally run into nicks in template DNA and collapse, generating double-strand ends. To model replication fork collapse in vivo, I constructed phage λ chromosomes carrying the nicking site of M13 bacteriophage and infected with these substrates Escherichia coli cells, producing M13 nicking enzyme. I detected double-strand breaks at the nicking sites in λ DNA purified from these cells. The double-strand breakage depends on (i) the presence of the nicking site; (ii) the production of the nicking enzyme; and (iii) replication of the nick-containing chromosome. Replication fork collapse at nicks in template DNA explains diverse phenomena, including eukaryotic cell killing by DNA topoisomerase inhibitors and inviability of recombination-deficient vertebrate cell lines.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- July 2001
- DOI:
- 10.1073/pnas.131009198
- Bibcode:
- 2001PNAS...98.8241K
- Keywords:
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- Colloquium Paper