Multilocus Imaging of the E. coli Chromosome by Fluorescent In Situ Hybridization

: Fluorescence in situ hybridization (FISH) is a widely used technique to detect and localize specific DNA or RNA sequences in cells. Although supplanted in many ways by fluorescently labeled DNA binding proteins, FISH remains the only cytological method to examine many genetic loci at once (up to six), and can be performed in any cell type and genotype. These advantages have proved invaluable in studying the spatial relationships between chromosome regions and the dynamics of chromosome segregation in bacteria. A detailed protocol for DNA FISH in E. coli is described.