Molecular cloning, characterization and regulation by cadmium of a superoxide dismutase from the ectomycorrhizal fungus Paxillus involutus

Christophe Jacob, Mikaël Courbot, Annick Brun, Howard M. Steinman, Jean Pierre Jacquot, Bernard Botton, Michel Chalot

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The gene encoding a superoxide dismutase (PiSOD) was cloned by suppressive subtractive hybridization from cDNA library of the ectomycorrhizal fungus, Paxillus involutus, grown under cadmium-stress conditions. The encoded protein was presumed to be localized in the peroxisomes because it contained a C-terminal peroxisomal localization peptide (SKL) and lacked an N-terminal mitochondrial transit peptide. Complementation of an Escherichia coli SOD null strain that is unable to grow in the presence of paraquat or cadmium indicated that cloned Pisod encoded a functional superoxide dismutase. Sensitivity of PiSOD activity to H2O2 but not KCN, and sequence homologies to other SODs strongly suggest that it is a manganese-containing superoxide dismutase. Monitoring PiSOD transcript, immunoreactive polypeptide and superoxide dismutase activity following cadmium stress suggests that the principal level of control is post-translational. This is, to our knowledge, the first insight in the characterization of molecular events that take place in an ectomycorrhizal fungus during exposure to heavy metals.

Original languageEnglish (US)
Pages (from-to)3223-3232
Number of pages10
JournalEuropean Journal of Biochemistry
Issue number11
StatePublished - Sep 17 2001



  • Cadmium
  • Complementation
  • Expression analysis
  • Paxillus involutus
  • Superoxide dismutase

ASJC Scopus subject areas

  • Biochemistry

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