E. coli growth inhibition by a high copy number derivative of plasmid pBR322

Biochem Biophys Res Commun. 1996 Feb 27;219(3):876-83. doi: 10.1006/bbrc.1996.0339.


We have observed that plasmid pKH47, a pBR322-derivative containing a 100bp poly(dA)-poly(dT) insertion, causes growth inhibition of host E. coli cells harboring it. In this paper we show that this inhibitory effect is due to an increased copy number property of this plasmid, which is turn leads to an over expression of the plasmid-encoded tet gene. Our work also indicates that contrary to other pleiotropic effects caused by the tet gene product, which solely depend on the expression of the 5' end of the gene, growth inhibition requires an intact tet gene. In addition we present the isolation of an E. coli mutant that is refractive to the inhibitory effect of pKH47 and shares some properties with the parental bacteria containing plasmid pKH4.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Composition
  • Base Sequence
  • Blotting, Southern
  • DNA Probes
  • Escherichia coli / drug effects
  • Escherichia coli / genetics*
  • Escherichia coli / growth & development*
  • Kanamycin / pharmacology
  • Kanamycin Resistance / genetics
  • Kinetics
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Mutagenesis, Insertional
  • Plasmids*
  • Poly dA-dT
  • Restriction Mapping
  • Species Specificity
  • Transformation, Bacterial


  • DNA Probes
  • Poly dA-dT
  • Kanamycin