Dr. Roy Magnuson

Dr. Roy Magnuson

Associate Professor, Molecular Microbiology


I am interested in addictive genetic elements and particularly. in the plasmid addiction operon from the P1 plasmid of Escherichia. This operon encodes two small proteins: a stable, 126 amino acid toxin and an unstable 73 amino acid antidote. While the plasmid is present, the antidote is expressed in sufficient quantities to bind and neutralize the toxin. Upon plasmid loss, the continuing degradation of the antidote by the host-encoded ClpXP protease unveils the toxin, which then kills the plasmid-free segregant. Current research is focused on the structure and function of antidote and toxin, and on the regulatory circuits that govern the level of antidote and the ratio of antidote and toxin.

Classes Taught


  • "Modulation of Cooperative Contacts between Phd and Doc." Journal of Bacteriology. Ferguson, Jenifer Lynn and Magnuson, Roy David (2005).
  • "Percolation of the Phd Repressor-Operator Interface." Journal of Bacteriology. Zhao, Xueyan and Magnuson, Roy David (2005).
  • "Characterization of the Phd Repressor-Antitoxin Boundary." Journal of Bacteriology. 187:765-770. McKinley, James Estle and Magnuson, Roy David (2005).
  • "Modular Organization of the Phd Repressor/Antitoxin Protein." Journal of Bacteriology. 186:2692-2698. Smith, Jeremy Allen, and Magnuson, Roy David. (2004).
  • "Corepression the P1 Addiction Operon by Phd and Doc." Journal of Bacteriology. 180:6342-6351. Magnuson, R. and Yarmolinsky, M. B. (1998).
  • "Autoregulation of the Plasmid Addiction Operon of Bacteriophage P1." Journal of Biological Chemistry. 271:18705-18710. Magnuson, R., Lehnherr, H., Mukhopadhyay, G. and Yarmolinsky, M. B. (1996).
  • "Convergent sensing pathways mediate response to two extracellular competence factors in Bacillus subtilis." Genes & Development. 9:547-558. Solomon, J., Magnuson, R., Srivastava, A. and Grossman, A. D. (1995).
  • "Biochemical and genetic characterization of a competence pheromone from B. subtilis." Cell. 77:207-216. Magnuson, R., Solomon, J. and Grossman, A. D. (1994).
  • "Signal transduction and the initiation of sporulation in Bacillus subtilis." Semin. Dev. Biol. 2:31-36. Grossman, A. D., Ireton, K., Hoff, E. F., LeDeaux, J. R., Rudner, D. Z., Magnuson, R. and Hicks, K. A. (1991).
  • "srfA is an operon required for surfactin production, competence development, and efficient sporulation in Bacillus subtilis." Journal of Bacteriology. 173: 1770-1778. Nakano, M. M., Magnuson, R., Meyers, A., Curry, J., Grossman, A. D. and Zuber, P. (1991).