Positioning of replicated chromosomes in Escherichia coli.

The positioning of replicated chromosomes at one-fourth and three-fourths of the cell length was inhibited when protein synthesis was inhibited by chloramphenicol or rifampin or by starvation for amino acids. Under these conditions, the progress of chromosome replication continued and replicated chromosomes were located close to each other as one nucleoid mass at midcell. Cells which already had two separate daughter chromosomes located at the cell quarters divided into two daughter cells under these conditions. When protein synthesis resumed, daughter chromosomes moved from midcell to the cell quarters, respectively, before any detectable increase in cell length was observed. The chromosome positioning occurred even under inhibition of the initiation of chromosome replication and under inactivation of DNA gyrase. The chromosome positioning presumably requires new synthesis of a particular protein(s) or translation itself.