Cell-cycle-specific initiation of replication.
The following characteristics are relevant when replication of chromosomes and plasmids is discussed in relation to the cell cycle: the timing or replication, the selection of molecules for replication, and the coordination of multiple initiation events within a single cell cycle. Several fundamentally different methods have been used to study these processes: Meselson-Stahl density-shift experiments, experiments with the so-called 'baby machine', sorting of cells according to size, and flow cytometry. The evidence for precise timing and co-ordination of chromosome replication in Escherichia coli is overwhelming. Similarly, the high-copy-number plasmid ColE1 and the low-copy-number plasmids R1/R100 without any doubt replicate randomly throughout the cell cycle. Data about the low-copy-number plasmids F and P1 are conflicting. This calls for new types of experiments and for a better understanding of how these plasmids control their replication and partitioning.
Department of Microbiology, Uppsala University, Sweden.
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Nordström
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Austin
D001431:Bacteriological Techniques / Q000295:instrumentation; D002453:Cell Cycle; D002876:Chromosomes, Bacterial; D004261:DNA Replication; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology; D005434:Flow Cytometry; D008957:Models, Genetic; D010957:Plasmids / Q000235:genetics; D012093:Replicon
D004269:DNA, Bacterial