title: Plasmid ColE1 DNA replication in Escherichia coli strains temperature-sensitive for DNA replication.
abstract: Mutants of the dnaA, dnaC, dnaD, polC, dnaF and dnaG gene loci were tested for their capacity for colicinogenic plasmid E1 (ColE1) replication at a non-permissive temperature. It was found that ColE1 replication was independent of the dnaA gene function and dependent on dnaC, D, F and G. ColE1 replication in the polC mutant E486 continued for several hours but at a greatly reduced rate. No effect was found of the dnaG mutation on thymine-deprivation-induced "priming" of ColE1 replication at the non-permissive temperature. The mutants also were tested for aberrant replication intermediates of plasmid DNA as well as a temperature sensitive supercoiled DNA-protein relaxation complex. RNA-containing supercoils were found to accumulate in a poIC mutant also blocked for protein synthesis.
authors.affiliation: Department of Biology, University of California, San Diego, La Jolla, California 92037, USA.
authors.forename: J
authors.initials: J
authors.lastname: Collins
authors.forename: P
authors.initials: P
authors.lastname: Williams
authors.forename: D R
authors.initials: DR
authors.lastname: Helinski
mesh_terms: D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics*; D004278:DNA, Superhelical / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D009154:Mutation; D010957:Plasmids; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical