Cloning and characterization of genes for the PvuI restriction and modification system

Nucleic Acids Res. 1992 Nov 11;20(21):5743-7. doi: 10.1093/nar/20.21.5743.


The genes encoding the endonuclease and the methylase of the PvuI restriction and modification system were cloned in E.coli and characterized. The genes were adjacent in tandem orientation spanning a distance of 2200 bases. The PvuI endonuclease was a single polypeptide with a calculated molecular weight of 27,950 daltons. The endonuclease was easily detectable when the gene was expressed from its endogenous promotor and present on a low copy plasmid, but expression was considerably enhanced when the endonuclease gene was placed under the control of a strong promoter on a high copy plasmid. The methylase did not completely protect plasmid DNA from R.PvuI digestion until the methylase gene was placed under lac promotor control in a multicopy plasmid. In the absence of the M.PvuI methylase, expression of the R.PvuI endonuclease from the lac promotor on a multicopy plasmid was not lethal to wild type E.coli, but was lethal in a temperature-sensitive ligase mutant at the non-permissive temperature. Moreover, induction of the R.PvuI endonuclease under lambda pL promotor control resulted in complete digestion of the E.coli chromosome by R.PvuI.

MeSH terms

  • Base Sequence
  • Chromosomes, Bacterial / metabolism
  • Cloning, Molecular
  • DNA Modification Methylases / genetics
  • DNA Modification Methylases / metabolism
  • DNA, Bacterial
  • Deoxyribonucleases, Type II Site-Specific / genetics*
  • Deoxyribonucleases, Type II Site-Specific / metabolism
  • Escherichia coli
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • Proteus vulgaris / enzymology
  • Proteus vulgaris / genetics
  • Restriction Mapping


  • DNA, Bacterial
  • DNA Modification Methylases
  • endodeoxyribonuclease PvuI
  • Deoxyribonucleases, Type II Site-Specific

Associated data

  • GENBANK/L04163