Cleavage of a model DNA replication fork by a Type I restriction endonuclease.

ABSTRACT: Cleavage of a DNA replication fork leads to fork restoration by recombination repair. In prokaryote cells carrying restriction-modification systems, fork passage reduces genome methylation by the modification enzyme and exposes the chromosome to attack by the restriction enzyme. Various observations have suggested a relationship between the fork and Type I restriction enzymes, which cleave DNA at a distance from a recognition sequence. Here, we demonstrate that a Type I restriction enzyme preparation cleaves a model replication fork at its branch. The enzyme probably tracks along the DNA from an unmethylated recognition site on the daughter DNA and cuts the fork upon encountering the branch point. Our finding suggests that these restriction-modification systems contribute to genome mainten

SUBMITTER: Ishikawa K 

PROVIDER: S-EPMC2699502 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature