Replication of plasmid R6K in DNA polymerase deficient mutants of Escherichia coli

Acta Microbiol Pol. 1978;27(4):321-9.


The plasmid R6K has been introduced into a number of Escherichia coli polymerase deficient (pol) mutants. In polCts mutants transferred to the nonpermissive temperature to inactivate polymerase III, R6K replicates but the replication products have a density in dye-CsCl gradients intermediate between supercoiled and linear forms. This aberrant replication requires normal cellular levels of polymerase I since it does not occur in polA polCts mutants. Normal R6K replication and maintenance occur in a polA polB polC+ host, however, we cannot tell from our experiments wheather polymerase I or III replicates R6K in polA+ polC+ host. Polymerase II, the polB gene product, has no detectable role in R6K replication.

MeSH terms

  • DNA Replication*
  • DNA, Bacterial / biosynthesis*
  • DNA, Circular / biosynthesis*
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Mutation
  • R Factors*


  • DNA, Bacterial
  • DNA, Circular
  • DNA-Directed DNA Polymerase