Send to

Choose Destination
See comment in PubMed Commons below
Nucleic Acids Res. 2009 Jun;37(11):3531-44. doi: 10.1093/nar/gkp214. Epub 2009 Apr 7.

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

Author information

  • 1Graduate Program in Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Tokyo 108-8639, Japan.


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 maintenance through cell death and indicates that DNA replication fork cleavage represents a critical point in genome maintenance to choose between the restoration pathway and the destruction pathway.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center