A DNA double-strand break can be efficiently repaired in Escherichia coli if an oligodeoxyribonucleotide is provided to direct the repair. The oligonucleotide must be at least 20 residues long and have a sequence identical to sequences flanking the break. The phenomenon can be used to introduce defined mutations into DNA in the area of a double-strand break. To obtain mutants, the oligonucleoti...

Ku protein binds to DNA ends and is a cofactor for the DNA-dependent protein kinase. Both of these components are involved in DNA double-strand break repair, but it has not been clear if they function indirectly, by sensing DNA damage and activating other factors, or if they are more directly involved in the processing and rejoining of DNA breaks. We demonstrate that intermolecular ligation of ...

DNA DSBs (double-strand breaks) represent a critical lesion for a cell, with misrepair being potentially as harmful as lack of repair. In mammalian cells, DSBs are predominantly repaired by non-homologous end-joining or homologous recombination. The kinetics of repair of DSBs can differ widely, and recent studies have shown that the higher-order chromatin structure can dramatically affect the p...

Direct attack to genomic DNA by reactive oxygen species causes various types of lesions, including base modifications and strand breaks. The most significant lesion is considered to be an unrepaired double-strand break that can lead to fatal cell damage. We directly observed double-strand breaks of DNA in reconstituted chromatin stained by a fluorescent cyanine dye, YOYO (quinolinium, 1,1'-[1,3...

In all cells, genetic recombination is used to repair DNA breaks and, as a result, genetic information is exchanged between homologous DNA molecules. Discontinuities in DNA strands, specifically double-strand DNA breaks and single-strand DNA gaps, attract the enzymes responsible for the initiation of homologous recombination. In wild-type Escherichia coli, two distinct pathways are responsible ...

DNA double-strand breaks (DSBs) pose a serious threat to genomic integrity. If unrepaired, they can lead to chromosome fragmentation and cell death. If repaired incorrectly, they can cause mutations and chromosome rearrangements. DSBs are repaired using end-joining or homology-directed repair strategies, with the predominant form of homology-directed repair being synthesis-dependent strand anne...