Complementation of a Saccharomyces cerevisiae ERG11/CYP51 (Sterol 14α-Demethylase) Doxycycline-Regulated Mutant and Screening of the Azole Sensitivity of Aspergillus fumigatus Isoenzymes CYP51A and CYP51B

Abstract

ABSTRACT Aspergillus fumigatus sterol 14α-demethylase isoenzymes CYP51A and CYP51B were heterologously expressed in a Saccharomyces cerevisiae mutant (YUG37- erg11 ), wherein native ERG11/CYP51 expression is controlled using a doxycycline-regulatable promoter. When cultured in the presence of doxycycline, recombinant YUG37-p cyp51A and YUG37-p cyp51B yeasts were able to synthesize ergosterol and grow; a control strain harboring reverse-oriented cyp51A could not. YUG37-p cyp51A and YUG37-p cyp51B constructs showed identical sensitivity to itraconazole, posaconazole, clotrimazole, and voriconazole. Conversely, YUG37-p cyp51A withstood 16-fold-higher concentrations of fluconazole than YUG37-p cyp51B (8 and 0.5 μg ml −1 , respectively).