Analysis of a Candida albicans gene that encodes a novel mechanism for resistance to benomyl and methotrexate

Mol Gen Genet. 1991 Jun;227(2):318-29. doi: 10.1007/BF00259685.


The pathogenic yeast, Candida albicans, is insensitive to the anti-mitotic drug, benomyl, and to the dihydrofolate reductase inhibitor, methotrexate. Genes responsible for the intrinsic drug resistance were sought by transforming Saccharomyces cerevisiae, a yeast sensitive to both drugs, with genomic C. albicans libraries and screening on benomyl or methotrexate. Restriction analysis of plasmids isolated from benomyl- and methotrexate-resistant colonies indicated that both phenotypes were encoded by the same DNA fragment. Sequence analysis showed that the fragments were nearly identical and contained a long open reading frame of 1694 bp (ORF1) and a small ORF of 446 bp (ORF2) within ORF1 on the opposite strand. By site-directed mutagenesis, it was shown that ORF1 encoded both phenotypes. The protein had no sequence similarity to any known proteins, including beta-tubulin, dihydrofolate reductase, and the P-glycoprotein of the multi-drug resistance family. The resistance gene was detected in several C. albicans strains and in C. stellatoidea by DNA hybridization and by the polymerase chain reaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Benomyl / pharmacology*
  • Candida albicans / drug effects*
  • Candida albicans / genetics
  • Codon / genetics
  • Drug Resistance, Microbial / genetics*
  • Escherichia coli / drug effects
  • Escherichia coli / genetics
  • Genes, Fungal*
  • Methotrexate / pharmacology*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Nucleic Acid Hybridization
  • Open Reading Frames / genetics
  • Polymerase Chain Reaction
  • Restriction Mapping
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / genetics


  • Codon
  • Benomyl
  • Methotrexate

Associated data

  • GENBANK/X53823