Escherichia coli contains a DNA replication compartment in the cell center

The active replication forks of E. coli B/r K cells growing with a doubling time of 210 min have been pulse-labeled with [H-3] thymidine for 10 min. B y electron-microscopic autoradiography the silver grains have been localize d in the various length classes. From the known pattern of the DNA replicat ion period in the cell cycle at slow growth and from the average position o f grains per length class it was deduced that DNA replication starts in the cell center and that it remains there for a substantial part of the DNA re plication period. This suggests the occurrence of a centrally located DNA r eplication compartment. (C) 1999 Societe francaise de biochimie et biologie moleculaire/Editions scientifiques et medicales Elsevier SAS.