Open AccessCloning of the lanosterol 14‐α‐demethylase ( ERG11 ) gene in T richosporon asahii : a possible association between G 453 R amino acid substitution and azole resistance in T . asahii
Author(s) -
Kushima Hisako,
Tokimatsu Issei,
Ishii Hiroshi,
Kawano Rie,
Shirai Ryo,
Kishi Kenji,
Hiramatsu Kazufumi,
Kadota Junichi
Publication year - 2012
Publication title -
fems yeast research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 92
eISSN - 1567-1364
pISSN - 1567-1356
DOI - 10.1111/j.1567-1364.2012.00816.x
Subject(s) - lanosterol , biology , azole , demethylase , amino acid , biochemistry , gene , microbiology and biotechnology , antifungal , epigenetics , sterol , cholesterol
Lanosterol 14‐α‐demethylase ( Erg11 protein; Erg11p ), encoded by the ERG11 gene, is the primary target of azoles. Recently, a change in affinity of this enzyme for azoles has been reported as a resistance mechanism in several fungal species. T richosporon asahii ( T . asahii) is susceptible to fluconazole ( FLC ). This report identified the ERG11 gene of T . asahii ( NCBI accession; HQ176415 ). The Erg11p of T . asahii , presumed from the DNA sequence, was closely related to the Erg11p of C ryptococcus neoformans . Furthermore, a FLC ‐susceptible strain was cultured in medium containing FLC at concentrations from 4.0 to 16 μg mL −1 in order to analyze the development of FLC resistance in T . asahii . The degree of resistance was related to the FLC concentration of the growth medium. One highly resistant strain that was cultured in the medium containing 16 μg mL −1 FLC contained 1 point mutation ( G 1357 C ) that caused a single amino acid substitution at G 453 R . This amino acid is highly conserved among major fungal pathogens, and it is in a region very close to the heme‐binding domain, which is characteristic of the cytochrome P 450 superfamily, the primary target for the azole class of antifungal agents. This amino acid substitution may have caused the high resistance to azoles in T . asahii .