RecN is a cohesin-like protein involved in DNA double-strand break repair in bacteria. The RecA recombinase functions to mediate repair via homologous DNA strand invasion to form D-loops. Here we provide evidence that the RecN protein stimulates the DNA strand invasion step of RecA-mediated recombinational DNA repair. The intermolecular DNA tethering activity of RecN protein described previousl...

Double-strand DNA breaks are the most lethal type of DNA damage induced by ionizing radiations. Previously, we reported that double-strand DNA breaks can be enzymatically produced from two DNA damages located on opposite DNA strands 18 or 30 base pairs apart in a cell-free double-strand DNA break formation assay (Vispé, S., and Satoh, M. S. (2000) J. Biol. Chem. 275, 27386-27392). In the assay ...

Double-strand breaks are widely accepted to be the most toxic form of DNA damage. Molecules that produce double-strand breaks via a single chemical event are typically very cytotoxic and far less common than those that form single-strand breaks. It was recently reported that a commonly formed C4'-radical produces double-strand breaks under aerobic conditions. Experiments described herein indica...

Homing endonuclease genes are "selfish" mobile genetic elements whose endonuclease promotes the spread of its own gene by creating a break at a specific target site and using the host machinery to repair the break by copying and inserting the gene at this site. Horizontal transfer across the boundary of a species or population within which mating takes place has been thought to be necessary for...

Double-strand DNA breaks occur upon exposure of cells to agents such as ionizing radiation and ultraviolet light or indirectly through replication fork collapse at DNA damage sites. If left unrepaired double-strand breaks can cause genome instability and cell death. In response to DNA damage, proteins involved in double-strand break repair by homologous recombination re-localize into discrete n...

We examined the influence that heterologous sequences of different sizes have on the frequency of double-strand-break repair by gene conversion in Drosophila melanogaster. We induced a double-strand break on one X chromosome in female flies by P-element excision. These flies contained heterologous insertions of various sizes located 238 bp from the break site in cis or in trans to the break, or...