Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Nature of the plasmid-linked penicillinase regulatory region in Staphylococcus aureus

  • 32 Accesses


Four noninducible staphylococcal penicillinase plasmids reported to produce a very low basal level of penicillinase were investigated. Incorporation of 5-methyltryptophan, which is known to inactivate the operator binding site of wild-type penicillinase repressor and thereby elicit penicillinase synthesis, did not induce penicillinase synthesis in any of these “micro” mutants. Therefore, these plasmids are not simply peni S mutants. Heterodiploid strains composed of a plasmid fully constitutive for penicillinase synthesis and one of the various “micro” penicillinase plasmids were constructed. Three of these heterodiploids produce a normal basal level of penicillinase and are inducible by 5-methyltryptophan but not by the standard gratuitous penicillinase inducer. Therefore, each of these three noninducible “micro” plasmids produces a peni S repressor, but in addition, each must bear a mutation in the penZ region. The fourth heterodiploid produces a fully constitutive level of penicillinase. The noninducible “micro” plasmid present in this heterodiploid must contain a penI mutation and a mutation in the penZ region. Consequently, each of these four noninducible “micro” plasmids contains at least two mutants genes. Hence, the phenotype of noninducibility plus low basal penicillinase is not due to a point mutation in a second penicillinase regulatory region as has been proposed. Instead, these results strongly suggest that there is only one penicillinase regulatory gene located on the penicillinase plasmid and that this gene (penI) specifies the penicillinase repressor.

This is a preview of subscription content, log in to check access.


  1. Ambler, R.P., Meadway, R.J.: Chemical structure of bacterial penicillinase. Nature (Lond.) 222, 24–26 (1969)

  2. Asheshov, E.H.: Loss of antibiotic resistance in Staphylococcus aureus resulting from growth at high temperature. J. gen. Microbiol. 42, 403–410 (1966)

  3. Cohen, S., Gibson, C.J., Sweeney, H.M.: Phenotypic suppression of methicillin resistance in Staphylococcus aureus by mutant noninducible penicillinase plasmids. J. Bact. 112, 682–689 (1972)

  4. Cohen, S., Sweeney, H.M.: Transduction of methicillin resistance in Staphylococcus aureus dependent on an unusual specificity of the recipient strain. J. Bact. 104, 1158–1167 (1970)

  5. Imsande, J.: Repressor and antirepressor in the regulation of staphylococcal penicillinase synthesis. Genetics 75, 1–17 (1973)

  6. Imsande, J., Lilleholm, J.L.: Characterization of mutations in the penicillinase operon of Staphylococcus aureus. Molec. gen. Genet. 147, 23–27 (1976)

  7. Imsande, J., Zyskind, J.W., Mile, I.: Regulation of staphylococcal penicillinase synthesis. J. Bact 109, 122–133 (1972)

  8. Lindberg, M., Novick, R.P.: Plasmid-specific transformation in Staphylococcus aureus. J. Bact. 115, 139–145 (1973)

  9. Novick, R.P.: Analysis by transduction of mutations affecting penicillinase formation in Staphylococcus aureus. J. gen. Microbiol. 33, 121–136 (1963)

  10. Perret, C.J.: Iodometric assay of penicillinase Nature (Lond.) 174, 1012–1013 (1954)

  11. Peyru, G., Wexler, L.F., Novick, R.P.: Naturally occurring penicillinase plasmids in Staphylococcus aureus. J. Bact. 98, 215–221 (1969)

  12. Richmond, M.H.: Dominance of the inducible state in strains of Staphylococcus aureus containing two distinet penicillinase plasmids. J. Bact. 90, 370–374 (1965)

  13. Richmond, M.H.: The genetic constitution of certain penicillinase micromutants in Staphylococcus aureus. J. gen. Microbiol. 45, 51–60 (1966)

  14. Richmond, M.H.: A second regulatory region involved in penicillinase synthesis in Staphylococcus aureus. J. molec. Biol. 26, 357–360 (1967)

Download references

Author information

Additional information

Journal Paper No. J-8700 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa; Project No. 2029

Communicated by W. Gilbert

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Imsande, J., Lilleholm, J.L. Nature of the plasmid-linked penicillinase regulatory region in Staphylococcus aureus . Molec. Gen. Genet. 153, 153–157 (1977).

Download citation


  • Binding Site
  • Regulatory Gene
  • Mutant Gene
  • Point Mutation
  • Staphylococcus Aureus