title: Escherichia coli K12 relA strains as safe hosts for expression of recombinant DNA.
abstract: Most Escherichia coli K12 strains survive for a relatively long time outside the laboratory. Under the same conditions the isoallelic E. coli K12 relA mutants die faster because they lack the stringent response. The killing rate is increased by using a plasmid-encoded suicide system consisting of the phage T7 lysozyme gene driven by the E. coli alkaline phosphatase gene promoter (phoA). Cells containing this system were rapidly and effectively killed as soon as phosphate was made limiting. The combination of the chromosomal relA mutation and a conditional suicide system of this type provides an effective means of biological containment for recombinant E. coli strains.
authors.affiliation: Institut für Mikrobiologie und Molekularbiologie, Ernst-Moritz-Arndt-Universität Greifswald, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Schweder
authors.forename: K
authors.initials: K
authors.lastname: Hofmann
authors.forename: M
authors.initials: M
authors.lastname: Hecker
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics; D017123:Bacteriophage T7 / Q000201:enzymology / Q000235:genetics; D001709:Biotechnology; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D003264:Containment of Biohazards; D004269:DNA, Bacterial / Q000235:genetics; D004274:DNA, Recombinant / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D015870:Gene Expression; D005798:Genes, Bacterial; D005804:Genes, Lethal; D005814:Genes, Viral; D008854:Microscopy, Electron; D009113:Muramidase / Q000235:genetics; D009154:Mutation; D010710:Phosphates / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D004274:DNA, Recombinant; D010710:Phosphates; D000469:Alkaline Phosphatase; D009113:Muramidase