DNA gyrase is a host factor required for transposition of Tn5

Ralph R. Isberg, Michael Syvanen

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


We show that DNA gyrase is required for transposition of Tn5. Coumermycin, a potent inhibitor of DNA gyrase subunit B, inhibits transposition in a wild-type strain, but has no effect on strains carry ing a coumermycin-resistant allele in gyrB. In addition, strains containing a thermolabile subunit A of gyrase (gyrA43) are defective for transposition at a nonpermissive temperature. The requirement for gyrase is due to a requirement for supercoiled DNA. We showed this by introducing into the gyrA43 strain a deletion of the gene encoding topoisomerase I. The introduction of the second mutation caused an increase in the superhelical density of DNA as well as an increase in the transposition frequency. This also implies that if the DNA is supercoiled there is no further requirement for gyrase. Experiments with coumermycin support this, because the drug does not inhibit transposition if the recipient DNA remains supercoiled. This indicates that if the DNA acting as recipient of the transposon is deficient in supercoils, it will be a poor substrate for transposition. We also describe a system in which a gene on a multicopy plasmid can be efficiently introduced into the Escherichia coli chromosome.

Original languageEnglish (US)
Pages (from-to)9-18
Number of pages10
Issue number1
StatePublished - 1982
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology


Dive into the research topics of 'DNA gyrase is a host factor required for transposition of Tn5'. Together they form a unique fingerprint.

Cite this