scholarly journals Fungal Zn(II)2Cys6 Transcription Factor ADS-1 Regulates Drug Efflux and Ergosterol Metabolism Under Antifungal Azole Stress

2020 ◽  
Author(s):  
Yajing Yin ◽  
Hanxing Zhang ◽  
Yu Zhang ◽  
Chengcheng Hu ◽  
Xianyun Sun ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Efflux Pump ◽  
Transcriptional Response ◽  
Fungal Species ◽  
Antifungal Drugs ◽  
Regulatory Function ◽  
Ergosterol Biosynthesis ◽  
Agricultural Practice ◽  
Transcriptional Responses ◽  
Basal Resistance

Antifungal azoles are the most widely used antifungal drugs in clinical and agricultural practice. Fungi can make adaptive responses to azole stress by modifying transcript levels of many genes and the responsive mechanisms to azoles are the basis for fungi to develop azole resistance. In this study, we identified a new Zn(II)2Cys6 transcription factor ADS-1 with a positive regulatory function in transcriptional responses to azole stress in the model filamentous fungal species Neurospora crassa. Under ketoconazole (KTC) stress, the transcript level of ads-1 was significantly increased in N. crassa. Deletion of ads-1 increased the susceptibility to different azoles while its overexpression increased resistance to these azoles. The gene cdr4, which encodes the key azole efflux pump, was positively regulated by ADS-1. Deletion of ads-1 reduced the transcriptional response by cdr4 to KTC stress and increased the cellular KTC accumulation under KTC stress while its overexpression had the opposite effect. ADS-1 also positively regulated transcriptional response by erg11, which encodes the azole target lanosterol 14α-demethylase for ergosterol biosynthesis, to KTC stress. After KTC treatment, the ads-1 deletion mutant had less ergosterol but accumulated more lanosterol than wild type, while ads-1 overexpression had the opposite effects. The homologs of ADS-1 widely present in filamentous fungal species of Ascomycota but not in yeasts. Deletion of the gene encoding ADS-1 homolog in Aspergillus flavus also increased the susceptibility to KTC and itraconazole (ITZ). Besides, deletion of Afads-1 significantly reduced the transcriptional response by genes encoding homologs of CDR4 and ERG11 in A. flavus to KTC stress and accumulated more KTC but less ergosterol. Together, the function and regulatory mechanism of ADS-1 homologs among different fungal species in azole responses and the basal resistance of azoles are highly conserved.

scholarly journals Transcription Factor ADS-4 Regulates Adaptive Responses and Resistance to Antifungal Azole Stress

2015 ◽  
Vol 59 (9) ◽  
pp. 5396-5404 ◽  
Author(s):  
Kangji Wang ◽  
Zhenying Zhang ◽  
Xi Chen ◽  
Xianyun Sun ◽  
Cheng Jin ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Efflux Pump ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Bzip Transcription Factor ◽  
Azole Resistance ◽  
Homologous Gene ◽  
Adaptive Responses ◽  
Transcriptional Responses ◽  
Content Type

ABSTRACTAzoles are commonly used as antifungal drugs or pesticides to control fungal infections in medicine and agriculture. Fungi adapt to azole stress by rapidly activating the transcription of a number of genes, and transcriptional increases in some azole-responsive genes can elevate azole resistance. The regulatory mechanisms that control transcriptional responses to azole stress in filamentous fungi are not well understood. This study identified a bZIP transcription factor, ADS-4 (antifungaldrugsensitive-4), as a new regulator of adaptive responses and resistance to antifungal azoles. Transcription ofads-4inNeurospora crassacells increased when they were subjected to ketoconazole treatment, whereas the deletion ofads-4resulted in hypersensitivity to ketoconazole and fluconazole. In contrast, the overexpression ofads-4increased resistance to fluconazole and ketoconazole inN. crassa. Transcriptome sequencing (RNA-seq) analysis, followed by quantitative reverse transcription (qRT)-PCR confirmation, showed that ADS-4 positively regulated the transcriptional responses of at least six genes to ketoconazole stress inN. crassa. The gene products of four ADS-4-regulated genes are known contributors to azole resistance, including the major efflux pump CDR4 (Pdr5p ortholog), an ABC multidrug transporter (NcAbcB), sterol C-22 desaturase (ERG5), and a lipid transporter (NcRTA2) that is involved in calcineurin-mediated azole resistance. Deletion of theads-4-homologous gene Afads-4inAspergillus fumigatuscaused hypersensitivity to itraconazole and ketoconazole, which suggested that ADS-4 is a functionally conserved regulator of adaptive responses to azoles. This study provides important information on a new azole resistance factor that could be targeted by a new range of antifungal pesticides and drugs.

scholarly journals The C2H2 Transcription Factor SltA Contributes to Azole Resistance by Coregulating the Expression of the Drug Target Erg11A and the Drug Efflux Pump Mdr1 in Aspergillus fumigatus

2021 ◽  
Author(s):  
Wenlong Du ◽  
Pengfei Zhai ◽  
Tingli Wang ◽  
Michael J Bromley ◽  
Yuanwei Zhang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Aspergillus Fumigatus ◽  
Fungal Pathogens ◽  
Efflux Pump ◽  
Antifungal Drugs ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Drug Efflux ◽  
Mobility Shift ◽  
Drug Efflux Pump

The emergence of azole-resistant fungal pathogens has posed a great threat to public health worldwide. Although the molecular mechanism of azole resistance has been extensively investigated, the potential regulators of azole resistance remain largely unexplored. Here we identified a new function of the fungal specific C2H2 zinc finger transcription factor SltA (involved in salt-tolerance pathway) in the regulation of azole resistance of the human fungal pathogen Aspergillus fumigatus. Lack of SltA results in an itraconazole hypersusceptibility phenotype. Transcriptional profiling combined with LacZ reporter analysis and electrophoretic mobility shift assays (EMSA) demonstrate that SltA is involved in its own transcriptional regulation and also regulates the expression of genes related to ergosterol biosynthesis (erg11A, erg13A and erg24A) and drug efflux pumps (mdr1, mfsC and abcE) by directly binding to the conserved 5’-AGGCA-3’ motif in their promoter regions, and this binding is dependent on the conserved cysteine and histidine within the C2H2 DNA binding domain of SltA. Moreover, overexpression of erg11A or mdr1 rescues sltA deletion defects under itraconazole conditions, suggesting that erg11A and mdr1 are related to sltA-mediated itraconazole resistance. Most importantly, deletion of SltA in laboratory-derived and clinical azole-resistant isolates significantly attenuates drug resistance. Collectively, we have identified a new function of the transcription factor SltA in regulating azole resistance by coordinately mediating the key azole target Erg11A and the drug efflux pump Mdr1, and targeting SltA may provide a potential strategy for intervention of clinical azole-resistant isolates to improve the efficiency of currently approved antifungal drugs.

scholarly journals Multiple mechanisms impact fluconazole resistance of mutant Erg11 proteins in Candida glabrata

2021 ◽  
Author(s):  
Bao Vu ◽  
W. Scott Moye-Rowley
Keyword(s):  
Transcription Factor ◽  
Candida Glabrata ◽  
Double Mutant ◽  
Antifungal Drugs ◽  
Cross Resistance ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Pathogenic Yeast ◽  
Fluconazole Resistance ◽  
Growth Defects

Azoles remain the most common used antifungal drugs for invasive candidiasis worldwide. They specifically inhibit the fungal lanosterol a-14 demethylase enzyme, which is commonly referred to as Erg11 in fungi. Inhibition of Erg11 ultimately leads to a reduction in ergosterol production, an essential fungal membrane sterol. Many Candida species, such as Candida albicans, develop mutations in this enzyme which reduces the azole binding affinity and results in increased azole resistance. Candida glabrata is also a pathogenic yeast that has a low intrinsic susceptibility to azole drugs and easily develops elevated resistance. These azole resistant mutations are almost exclusively found to cause hyperactivity of the Pdr1 transcription factor and rarely lie within the ERG11 gene. Here, we generated C. glabrata ERG11 mutations that were analogous to azole resistance associated mutations in C. albicans ERG11. Three different Erg11 forms (Y141H, S410F, and the corresponding double mutant (DM)) conferred azole resistance in C. glabrata with the DM Erg11 form causing the strongest phenotype. The DM Erg11 also induced cross-resistance to amphotericin B and caspofungin. The azole resistance caused by the DM allele of ERG11 imposed a fitness cost that was not observed with hyperactive PDR1 alleles. These data support the view that C. glabrata does not typically acquire ERG11 mutations owing to growth defects associated with these lesions while hyperactive PDR1 alleles have no obvious growth issues. Understanding the physiology linking ergosterol biosynthesis with Pdr1-mediated regulation of azole resistance is crucial for ensuring the continued efficacy of azole drugs against C. glabrata.

TSHZ2 is an EGF-regulated tumor suppressor that binds to the cytokinesis regulator PRC1 and inhibits metastasis

2021 ◽  
Vol 14 (688) ◽  
pp. eabe6156
Author(s):  
Mary L. Uribe ◽  
Maik Dahlhoff ◽  
Rajbir N. Batra ◽  
Nishanth B. Nataraj ◽  
Yuya Haga ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Tumor Suppressors ◽  
Mammalian Cells ◽  
Transcriptional Response ◽  
Distinct Group ◽  
Cyclin B1 ◽  
Prolonged Treatment ◽  
Transcriptional Responses ◽  
Tumor Growth And Metastasis ◽  
Transcription Factor P53

Unlike early transcriptional responses to mitogens, later events are less well-characterized. Here, we identified delayed down-regulated genes (DDGs) in mammary cells after prolonged treatment with epidermal growth factor (EGF). The expression of these DDGs was low in mammary tumors and correlated with prognosis. The proteins encoded by several DDGs directly bind to and inactivate oncoproteins and might therefore act as tumor suppressors. The transcription factor teashirt zinc finger homeobox 2 (TSHZ2) is encoded by a DDG, and we found that overexpression of TSHZ2 inhibited tumor growth and metastasis and accelerated mammary gland development in mice. Although the gene TSHZ2 localizes to a locus (20q13.2) that is frequently amplified in breast cancer, we found that hypermethylation of its promoter correlated with down-regulation of TSHZ2 expression in patients. Yeast two-hybrid screens and protein-fragment complementation assays in mammalian cells indicated that TSHZ2 nucleated a multiprotein complex containing PRC1/Ase1, cyclin B1, and additional proteins that regulate cytokinesis. TSHZ2 increased the inhibitory phosphorylation of PRC1, a key driver of mitosis, mediated by cyclin-dependent kinases. Furthermore, similar to the tumor suppressive transcription factor p53, TSHZ2 inhibited transcription from the PRC1 promoter. By recognizing DDGs as a distinct group in the transcriptional response to EGF, our findings uncover a group of tumor suppressors and reveal a role for TSHZ2 in cell cycle regulation.

scholarly journals A Role for Iron-Sulfur Clusters in the Regulation of Transcription Factor Yap5-dependent High Iron Transcriptional Responses in Yeast

2012 ◽  
Vol 287 (42) ◽  
pp. 35709-35721 ◽  
Author(s):  
Liangtao Li ◽  
Ren Miao ◽  
Sophie Bertram ◽  
Xuan Jia ◽  
Diane M. Ward ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Target Genes ◽  
Transcriptional Response ◽  
Regulation Of Transcription ◽  
Transcriptional Responses ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
High Iron ◽  
Iron Sulfur

Yeast respond to increased cytosolic iron by activating the transcription factor Yap5 increasing transcription of CCC1, which encodes a vacuolar iron importer. Using a genetic screen to identify genes involved in Yap5 iron sensing, we discovered that a mutation in SSQ1, which encodes a mitochondrial chaperone involved in iron-sulfur cluster synthesis, prevented expression of Yap5 target genes. We demonstrated that mutation or reduced expression of other genes involved in mitochondrial iron-sulfur cluster synthesis (YFH1, ISU1) prevented induction of the Yap5 response. We took advantage of the iron-dependent catalytic activity of Pseudaminobacter salicylatoxidans gentisate 1,2-dioxygenase expressed in yeast to measure changes in cytosolic iron. We determined that reductions in iron-sulfur cluster synthesis did not affect the activity of cytosolic gentisate 1,2-dioxygenase. We show that loss of activity of the cytosolic iron-sulfur cluster assembly complex proteins or deletion of cytosolic glutaredoxins did not reduce expression of Yap5 target genes. These results suggest that the high iron transcriptional response, as well as the low iron transcriptional response, senses iron-sulfur clusters.

scholarly journals Role of Candida albicans Transcription Factor Upc2p in Drug Resistance and Sterol Metabolism

2004 ◽  
Vol 3 (6) ◽  
pp. 1391-1397 ◽  
Author(s):  
Peter M. Silver ◽  
Brian G. Oliver ◽  
Theodore C. White
Keyword(s):  
Drug Resistance ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Transmembrane Domain ◽  
Homozygous Deletion ◽  
Antifungal Drugs ◽  
Deletion Strain ◽  
Ergosterol Biosynthesis ◽  
Heterozygous Deletion ◽  
Nuclear Localization Signals

ABSTRACT In Candida albicans, drug resistance to clinically important antifungal drugs may be regulated through the action of transcription factors in a manner that may or may not be similar to regulation in Saccharomyces cerevisiae. A search of the C. albicans genome identified a single homolog of the S. cerevisiae transcription factor genes UPC2 (ScUPC2) and ECM22 (ScECM22) that have been associated with regulation of ergosterol biosynthesis. Sequence analysis of this C. albicans UPC2 (CaUPC2) gene identifies two domains, an anchoring transmembrane domain and a transcription factor region containing multiple nuclear localization signals and a fungal Zn(2)-Cys(6) binuclear cluster domain. Heterozygous deletion, homozygous deletion, and reconstructed strains of CaUPC2 as well as the parental strain were tested against several antifungal drugs, including ergosterol biosynthesis inhibitors. The CaUPC2 homozygous deletion strain showed marked hypersusceptibility to most drugs, compared to the parental and reconstructed strains. The deletion strains accumulate significantly less radiolabeled cholesterol, suggesting reduced ergosterol scavenging in those strains. When grown under azole drug pressure, the parental, heterozygous deletion and reconstructed strains of CaUPC2 upregulate the ERG2 and ERG11 ergosterol biosynthesis genes, while the homozygous deletion strain shows no such upregulation. Consistent with these results, CaUPC2 deletion strains show reduced ergosterol levels, which may explain the increased susceptibilities of the CaUPC2 deletion strains. Thus, it appears that CaUPC2 acts as a transcription factor involved in the regulation of ergosterol biosynthetic genes and as a regulator of sterol uptake across the plasma membrane.

scholarly journals Permissive epigenetic landscape facilitates distinct transcriptional signatures of activating transcription factor 6 in the liver

2021 ◽  
Author(s):  
Anjana Ramdas Nair ◽  
Priyanka Lakhiani ◽  
Chi Zhang ◽  
Filippo Macchi ◽  
Kirsten C. Sadler
Keyword(s):  
Transcription Factor ◽  
Target Genes ◽  
Expression Patterns ◽  
Transcriptional Response ◽  
Differentially Expressed ◽  
Small Subset ◽  
Gene Promoters ◽  
Transcriptional Responses ◽  
Functional Studies ◽  
Activating Transcription Factor

ABSTRACTProteostatic stress initiates a transcriptional response that is unique to the stress condition, yet the regulatory mechanisms underlying the distinct gene expression patterns observed in stressed cells remains unknown. Using a functional genomic approach, we investigated how activating transcription factor 6 (ATF6), a key transcription factor in the unfolded protein response (UPR), regulates target genes. We first designed a computational strategy to define Atf6 target genes based on the evolutionary conservation of predicted ATF6 binding in gene promoters, identifying 652 conserved putative Atf6 target (CPAT) genes. CPATs were overrepresented for genes functioning in the UPR, however, the majority functioned in cellular processes unrelated to proteostasis, including small molecule metabolism and development. Functional studies of stress-independent and toxicant based Atf6 activation in zebrafish livers showed that the pattern of CPAT expression in response to Atf6 overexpression, alcohol and arsenic was unique. Only 34 CPATs were differentially expressed in all conditions, indicating that Atf6 is sufficient to regulate a small subset of CPATs. Blocking Atf6 using Ceapins in zebrafish demonstrated that Atf6 is necessary for activation of these genes in response to arsenic. We investigated CPAT during physiologically mediated hepatocyte stress using liver regeneration in mice as a model. Over half of all CPATs were differentially expressed during this process. This was attributed to the permissive chromatin environment in quiescent livers on the promoters of these genes, characterized by the absence of H3K27me3 and enrichment of H3K4me3. Taken together, these data uncover a complex transcriptional response to Atf6 activation and implicate a permissive epigenome as a mechanism by which distinct transcriptional responses are regulated by Atf6.

scholarly journals cis-Acting Elements within the Candida albicans ERG11 Promoter Mediate the Azole Response through Transcription Factor Upc2p

2007 ◽  
Vol 6 (12) ◽  
pp. 2231-2239 ◽  
Author(s):  
Brian G. Oliver ◽  
Jia L. Song ◽  
Jake H. Choiniere ◽  
Theodore C. White
Keyword(s):  
Transcription Factor ◽  
Candida Albicans ◽  
Regulatory Elements ◽  
Antifungal Drugs ◽  
Start Codon ◽  
Luciferase Reporter ◽  
Ergosterol Biosynthesis ◽  
Luciferase Reporter Gene ◽  
Enhancer Element

ABSTRACT The azole antifungal drugs are used to treat infections caused by Candida albicans and other fungi. These drugs interfere with the biosynthesis of ergosterol, the major sterol in fungal cells, by inhibiting an ergosterol biosynthetic enzyme, lanosterol 14 α-demethylase, encoded by the ERG11 gene. In vitro, these drugs as well as other ergosterol biosynthesis inhibitors increase ERG11 mRNA expression by activation of the ERG11 promoter. The signal for this activation most likely is the depletion of ergosterol, the end product of the pathway. To identify cis-acting regulatory elements that mediate this activation, ERG11 promoter fragments have been fused to the luciferase reporter gene from Renilla reniformis. Promoter deletions and linker scan mutations localized the region important for azole induction to a segment from bp −224 to −251 upstream of the start codon, specifically two 7-bp sequences separated by 13 bp. These sequences form an imperfect inverted repeat. The region is recognized by the transcription factor Upc2p and functions as an enhancer of transcription, as it can be placed upstream of a heterologous promoter in either direction, resulting in the azole induction of that promoter. The promoter constructs are not azole inducible in the upc2/upc2 homozygous deletion, demonstrating that Upc2p controls the azole induction of ERG11. These results identify an azole-responsive enhancer element (ARE) in the ERG11 promoter that is controlled by the Upc2p transcription factor. No other ARE is present in the promoter. Thus, this ARE and Upc2p are necessary and sufficient for azole induction of ERG11.

scholarly journals Transcriptional Response of Saccharomyces cerevisiae to the Plasma Membrane-Perturbing Compound Chitosan

2005 ◽  
Vol 4 (4) ◽  
pp. 703-715 ◽  
Author(s):  
Anna Zakrzewska ◽  
Andre Boorsma ◽  
Stanley Brul ◽  
Klaas J. Hellingwerf ◽  
Frans M. Klis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Transcription Factor ◽  
Plasma Membrane ◽  
Transcriptional Response ◽  
Wall Stress ◽  
Yeast Cells ◽  
Transcriptional Responses ◽  
Cell Wall Stress ◽  
Spoilage Yeast

ABSTRACT Chitosan is a plasma membrane-perturbing compound consisting of linear chains of β-1,4-linked glucosamine residues, which at acidic pHs become positively charged. It is extensively used as an antimicrobial compound, yet its mode of action is still unresolved. Chitosan strongly affected the growth of the yeast Saccharomyces cerevisiae, the food spoilage yeast Zygosaccharomyces bailii, and two human-pathogenic yeasts, Candida albicans and Candida glabrata. Microarray analysis of yeast cells treated with sublethal concentrations of chitosan revealed induction of the environmental stress response and three more major transcriptional responses. The first was a rapid and stable Cin5p-mediated response. Cin5p/Yap4p is a transcription factor involved in various stress responses. Deletion of CIN5 led to increased chitosan sensitivity. The second was a Crz1p-mediated response, which is delayed compared to the Cin5p response. Crz1p is a transcription factor of the calcineurin pathway. Cells deleted for CRZ1 or treated with the calcineurin inhibitor FK506 became hypersensitive to chitosan, supporting the notion that the Crz1p-controlled response offers protection against chitosan. The third was a strong Rlm1p-mediated response which ran parallel in time with the Crz1p-regulated response. Rlm1p is a transcription factor of the cell wall integrity pathway, which is activated by cell wall stress. Importantly, chitosan-treated cells became more resistant to β-1,3-glucanase, which is a well-known response to cell wall stress. We propose that the transcriptional response to chitosan may be representative of other plasma membrane-perturbing compounds.

Azole-resistant alleles of ERG11 in Candida glabrata trigger activation of the Pdr1 and Upc2A transcription factors.

2022 ◽  
Author(s):  
Bao Gia Vu ◽  
W. Scott Moye-Rowley
Keyword(s):  
Transcription Factor ◽  
Candida Albicans ◽  
Candida Glabrata ◽  
Double Mutant ◽  
Antifungal Drugs ◽  
Cross Resistance ◽  
Ergosterol Biosynthesis ◽  
Azole Resistance ◽  
Pathogenic Yeast ◽  
Cellular Effects

Azoles, the most commonly used antifungal drugs, specifically inhibit the fungal lanosterol α-14 demethylase enzyme, which is referred to as Erg11. Inhibition of Erg11 ultimately leads to a reduction in ergosterol production, an essential fungal membrane sterol. Many Candida species, such as Candida albicans , develop mutations in this enzyme which reduces the azole binding affinity and results in increased resistance. Candida glabrata is also a pathogenic yeast that has low intrinsic susceptibility to azole drugs and easily develops elevated resistance. In C. glabrata , these azole resistant mutations typically cause hyperactivity of the Pdr1 transcription factor and rarely lie within the ERG11 gene. Here, we generated C. glabrata ERG11 mutations that were analogous to azole resistance alleles from C. albicans ERG11 . Three different Erg11 forms (Y141H, S410F, and the corresponding double mutant (DM)) conferred azole resistance in C. glabrata with the DM Erg11 form causing the strongest phenotype. The DM Erg11 also induced cross-resistance to amphotericin B and caspofungin. Resistance caused by the DM allele of ERG11 imposed a fitness cost that was not observed with hyperactive PDR1 alleles. Crucially, the presence of the DM ERG11 allele was sufficient to activate the Pdr1 transcription factor in the absence of azole drugs. Our data indicate that azole resistance linked to changes in ERG11 activity can involve cellular effects beyond an alteration in this key azole target enzyme. Understanding the physiology linking ergosterol biosynthesis with Pdr1-mediated regulation of azole resistance is crucial for ensuring the continued efficacy of azole drugs against C. glabrata .

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