Journal article
Differential Functions of Individual Transcription Factor Binding Sites in the Tandem Repeats Found in Clinically Relevant cyp51A Promoters in Aspergillus fumigatus
mBio, Vol.13(3), pp.e0070222-e0070222
04/25/2022
DOI: 10.1128/mbio.00702-22
PMCID: PMC9239056
PMID: 35467427
Abstract
Aspergillus fumigatus
is the most common human filamentous fungal pathogen. Azole drugs are the current therapy of choice for
A. fumigatus
, but the prevalence of azole resistance is increasing.
ABSTRACT
Aspergillus fumigatus
is the major filamentous fungal pathogen in humans. The gold standard treatment of
A. fumigatus
is based on azole drug use, but the appearance of azole-resistant isolates is increasing at an alarming rate. The
cyp51A
gene encodes the enzymatic target of azole drugs, and azole-resistant alleles of
cyp51A
often have an unusual genetic structure containing a duplication of a 34- or 46-bp region in the promoter causing enhanced gene transcription. These tandem repeats are called TR34 and TR46 and produce duplicated binding sites for the SrbA and AtrR transcription factors. Using site-directed mutagenesis, we demonstrate that both the SrbA (sterol response element [SRE]) and AtrR binding sites (AtrR response element [ATRE]) are required for normal
cyp51A
gene expression. Loss of either the SRE or ATRE from the distal 34-bp repeat of the TR34 promoter (further 5′ from the transcription start site) caused loss of expression of
cyp51A
and decreased voriconazole resistance. Surprisingly, loss of these same binding sites from the proximal 34- or 46-bp repeat led to increased
cyp51A
expression and voriconazole resistance. These data indicate that these duplicated regions in the
cyp51A
promoter function differently. Our findings suggest that the proximal 34- or 46-bp repeat in
cyp51A
recruits a corepressor that requires multiple factors to act while the distal repeat is free of this repression and provides the elevated
cyp51A
expression caused by these promoter duplications.
IMPORTANCE
Aspergillus fumigatus
is the most common human filamentous fungal pathogen. Azole drugs are the current therapy of choice for
A. fumigatus
, but the prevalence of azole resistance is increasing. The main genetic alteration causing azole resistance is a change in the
cyp51A
gene, which encodes the target of these drugs. Azole-resistant
cyp51A
alleles routinely contain duplications in their promoter regions that cause increased gene transcription. Here, we demonstrate that clinical isolates containing a 34- or 46-bp duplication in the
cyp51A
promoter required the presence of the transcription factor-encoding
atrR
gene to exhibit elevated azole resistance. Eliminations of transcription factor binding sites in the
cyp51A
gene have differential actions on expression of the resulting mutant allele. These data dissect the molecular inputs to
cyp51A
transcription and reveal a complicated function of the promoter of this gene that is critical in azole resistance.
Details
- Title: Subtitle
- Differential Functions of Individual Transcription Factor Binding Sites in the Tandem Repeats Found in Clinically Relevant cyp51A Promoters in Aspergillus fumigatus
- Creators
- Sanjoy Paul - University of IowaPaul E. Verweij - Radboud University Nijmegen Medical CentreWillem J. G. Melchers - Radboud University Nijmegen Medical CentreW. Scott Moye-Rowley - Roy J. and Lucille A. Carver College of Medicine
- Contributors
- Gustavo H. Goldman (Editor)
- Resource Type
- Journal article
- Publication Details
- mBio, Vol.13(3), pp.e0070222-e0070222
- DOI
- 10.1128/mbio.00702-22
- PMID
- 35467427
- PMCID
- PMC9239056
- NLM abbreviation
- mBio
- ISSN
- 2150-7511
- eISSN
- 2150-7511
- Grant note
- DOI: 10.13039/100000060, name: HHS | NIH | National Institute of Allergy and Infectious Diseases, award: AI143198
- Language
- English
- Date published
- 04/25/2022
- Academic Unit
- Molecular Physiology and Biophysics; Internal Medicine
- Record Identifier
- 9984297604702771
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