Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK.
It has long been known that the 5' to 3' polarity of DNA synthesis results in both a leading and lagging strand at all replication forks. Until now, however, there has been no evidence that leading or lagging strands are spatially organized in any way within a cell. Here we show that chromosome segregation in Escherichia coli is not random but is driven in a manner that results in the leading and lagging strands being addressed to particular cellular destinations. These destinations are consistent with the known patterns of chromosome segregation. Our work demonstrates a new level of organization relating to the replication and segregation of the E. coli chromosome.