Methanol and acriflavine resistance in Dictyostelium are caused by loss of catalase.
Various chemicals with harmful effects are not themselves toxic, but are metabolized in vivo to produce toxic products. One example is methanol in Dictyostelium, which is lethal to cells containing the acrA gene, but relatively harmless to acrA mutants. This makes methanol resistance one of the tightest genetic selections in DICTYOSTELIUM: Loss of acrA also confers cross-resistance to unrelated compounds such as acriflavine and thiabendazole. We have used insertional mutagenesis to demonstrate that the acrA locus encodes the peroxisomal catalase A enzyme. Disruption of the catA gene results in parallel resistance to acriflavine. Molecular and biochemical studies of several previously characterized methanol-resistant strains reveal that each lacks catalase activity. One allele, acrA2, contains a 13 bp deletion which introduces a frameshift in the middle of the gene. The involvement of catalase in methanol resistance in Dictyostelium compares with its role in methanol metabolism in yeast and rodents. However, this is the first study to show that catalase is required for the toxicity of acriflavine. Our results imply that acriflavine and thiabendazole are precursors which must be oxidized to generate biologically active species. The catA/acrA gene is also a potentially invaluable negative selectable marker for Dictyostelium molecular genetics.
Garcia
Ma Xenia U
MXU
Division of Biological Sciences, University of Missouri, Columbia, MO 65211-7400, USA1.
Roberts
Catherine
C
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK2.
Alexander
Hannah
H
Division of Biological Sciences, University of Missouri, Columbia, MO 65211-7400, USA1.
Stewart
A Michael
AM
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK2.
Harwood
Adrian
A
Laboratory for Molecular Cell Biology, UCL, Gower Street, London WC1E 6BT, UK3.
Alexander
Stephen
S
Division of Biological Sciences, University of Missouri, Columbia, MO 65211-7400, USA1.
Insall
Robert H
RH
School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK2.
D000167:Acriflavine / Q000494:pharmacology*; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D004023:Dictyostelium / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D004351:Drug Resistance / Q000235:genetics; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism; D026901:Membrane Transport Proteins; D000432:Methanol / Q000494:pharmacology*; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism
C083497:AcrA protein, E coli; D000891:Anti-Infective Agents, Local; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; D026901:Membrane Transport Proteins; D015800:Protozoan Proteins; D000167:Acriflavine; D002374:Catalase; D000432:Methanol