Tagging of genes involved in multidrug resistance in Aspergillus nidulans.
We have used a plasmid containing the Neurospora crassa pyr4 gene to transform an Aspergillus nidulans pyrG89 mutant strain in the presence of Bam-HI, and isolated multidrug-sensitive mutants among the transformants. Using this approach, we hoped to identify genes whose products are important for drug resistance by analyzing gene disruptions that alter the drug sensitivity of the cell. About 1300 transformants isolated following transformation were screened for sensitivity to drugs or various stress agents with different and/or the same mechanism of action. Seventy-seven of these transformants showed sensitivity to at least one drug, while fourteen transformants showed a complex phenotype of sensitivity to different drugs. The pyr4 marker was shown to be tightly linked to the mutant phenotype in only 36% of the pleiotropic mutants analyzed in sexual crosses. Genetic crosses between our multidrug-sensitive transformants and cycloheximide-sensitive and imazalil-resistant mutants of A nidulans were performed to determine whether mutations were present at the same loci. We have shown that the gene imaD that confers resistance to imazalil may also be involved in cycloheximide and hygromycin sensitivity, since this mutation is allelic to scyB (mutant scy290). In addition, the cross between the transformant R223 and the imazalil-resistant mutant ima535 showed that both mutations are in the same complementation group, suggesting that the gene imaG could also be involved in cycloheximide and itraconazole sensitivity.
de Souza
C C
CC
Departamento de Ciências Farmacêuticas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Brazil.
Goldman
M H
MH
Goldman
G H
GH
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology; D001233:Aspergillus nidulans / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D002262:Carboxy-Lyases; D003513:Cycloheximide / Q000494:pharmacology; D018432:Drug Resistance, Multiple / Q000235:genetics*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D005659:Fungicides, Industrial / Q000494:pharmacology; D005838:Genotype; D007093:Imidazoles / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D009492:Neurospora crassa / Q000235:genetics*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010641:Phenotype; D010957:Plasmids; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D014170:Transformation, Genetic
D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000935:Antifungal Agents; D005656:Fungal Proteins; D005659:Fungicides, Industrial; D007093:Imidazoles; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; C017435:enilconazole; D003513:Cycloheximide; D002262:Carboxy-Lyases; C096137:pyr4 protein, Rhizopus