Loss-of-function ROX1 mutations suppress the fluconazole susceptibility of upc2A∆ mutation in Candida glabrata, implicating additional positive regulators of ergosterol biosynthesis
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ABSTRACT:
PROVIDER: PRJNA789874 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR17263150_1.fastq.gz | Fastqsanger.gz | |||
| SRR17263150_2.fastq.gz | Fastqsanger.gz | |||
| SRR17263151_1.fastq.gz | Fastqsanger.gz | |||
| SRR17263151_2.fastq.gz | Fastqsanger.gz | |||
| SRR17263152_1.fastq.gz | Fastqsanger.gz |
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Project description:Two of the major classes of antifungal drugs in clinical use target ergosterol biosynthesis. Despite its importance, our understanding of the transcriptional regulation of ergosterol biosynthesis genes in pathogenic fungi is essentially limited to the role of hypoxia and sterol-stress induced transcription factors such as Upc2 and Upc2A as well as homologs of Sterol Response Element Binding (SREB) factors. To identify additional regulators of ergosterol biosynthesis in Candida glabrata, an important human fungal pathogen with reduced susceptibility to ergosterol biosynthesis inhibitors relative to other Candida spp., we used a serial passaging strategy to isolate suppressors of the fluconazole hypersusceptibility of a upc2A∆ deletion mutant. This led to the identification of loss of function mutants in two genes: ROX1, the homolog of a hypoxia gene transcriptional suppressor in Saccharomyces cerevisiae, and CST6, a transcription factor that is involved in the regulation of carbon dioxide response in C. glabrata. Here, we describe a detailed analysis of the genetic interaction of ROX1 and UPC2A. In the presence of fluconazole, loss of Rox1 function restores ERG11 expression to the upc2A∆ mutant and inhibits the expression of ERG3 and ERG6, leading to increased levels or ergosterol and decreased levels of the toxic sterol, 14α methyl-ergosta-8,24(28)-dien-3β, 6α-diol, relative to upc2A∆. Our observations establish that Rox1 is a negative regulator of ERG gene biosynthesis and indicate that a least one additional positive transcriptional regulator of ERG gene biosynthesis must be present in C. glabrata.
2021-12-20 | GSE191145 | GEO
Project description:Purpose: Compare the fluconazole-induced transcriptome of isogenic wild-type and upc2A null cells. Methods: Prepare total RNA from wild-type and upc2A null cells grown under unstressed conditions or challenged with 50 microgram/ml fluconazole for 6 hours. Use standard RNA-seq to evaluate and compare the transcriptomic changes caused by fluconazole in the presence or absence of UPC2A. Results: These data established that over 100 genes were induced by fluconazole in a UPC2A-dependent manner. However, most fluconazole-induced genes (>500) did not require the presence of UPC2A. Fluconazole-induced genes included the expected genes involved in ergosterol biosynthesis but also large number of plasma membrane-localized transporters. Conclusions: These data suggest that Upc2A provided transcriptional co-regulation between membrane transporters and the lipid environment in which these proteins function. A significant portion of the fluconazole-induced transcriptome does not require the presence of Upc2A, suggesting the presence of other transcriptional circuits responsive to this pharmacologic block of ergosterol biosynthesis.
2021-09-23 | GSE182489 | GEO
Project description:Purpose: Determine the number of genes that respond to the presence of a gain-of-function mutant form of the UPC2A transcription factor in Candida glabrata. Methods: Prepare total RNA from wild-type and gain-of-function G898D UPC2A cells. Use standard RNA-seq to evaluate and compare the transcriptomic changes caused by this allele of UPC2A. Results: Although a clear increase was seen in fluconazole resistance conferred by the G898D UPC2A allele, elevated transcription was only observed for 11 genes with 9 of these involved in ergosterol biosynthesis. Conclusions: The presence of the G898D UPC2A allele led to elevated constitutive transcription for genes involved in ergosterol biosynthesis.
2021-09-23 | GSE182490 | GEO
Project description:To determine the genomic binding sites for the Candida glabrata transcription factor Upc2A, we utilized three different strains. One was the wild-type KKY2001 which contains a wild-type copy of UPC2A but lacks any HA tag. The other two are both derived from KKY2001 but contain a 3X HA tag immediately after the start codon of UPC2A. These strains are BVGC82 and BVGC84, respectively. Both contain a single copy of a loxP element located 252 bp downstream from the UPC2A stop codon. BVGC82 contains a wild-type copy of the UPC2A gene while BVGC84 contains a mutant form of UPC2A (G898D) that confers elevated resistance to fluconazole. ChIP was performed with anti-HA antibodies in all cases. Strains containing the wild-type UPC2A gene (no HA tag) are referred to as C1 and C2. Strains containing the 3X HA epitope tag at the N-terminus of the wild-type UPC2A gene are referred to as wt1 and wt2. These same strains challenged with fluconazole prior to ChIP are referred to as wtf1 and wtf2. The strain containing the G898D UPC2A allele are referred to as M1 and M2 (no fluconazole challenge) and MF1 and MF2 (with fluconazole challenge.
2021-09-23 | GSE182488 | GEO
Project description:RNA-sequencing analysis of fluconazole-treated wild-type and upc2A null cells [Fluconazole]
| PRJNA756363 | ENA
Project description:In the pathogenic yeast Candida albicans, the zinc cluster transcription factor Upc2p has been shown to regulate expression of ERG11 and other genes involved in ergosterol biosynthesis upon exposure to azole antifungals. ERG11 encodes lanosterol demethylase, the target enzyme of this antifungal class. Over-expression of UPC2 reduces azole susceptibility, whereas its disruption results in hypersusceptibility to azoles and reduced accumulation of exogenous sterols. Constitutive up-regulation of ERG11 is a major cause of resistance to fluconazole in clinical isolates of C. albicans, yet the mechanism for this has yet to be determined. Using genome-wide gene expression profiling, we found UPC2 and other genes involved in ergosterol biosynthesis to be coordinately up-regulated with ERG11 in a fluconazole resistant clinical isolate as compared with a matched susceptible isolate from the same patient. Sequence analysis of the UPC2 alleles of these isolates revealed that the resistant isolate contained a single nucleotide substitution in one UPC2 allele that resulted in a G648D exchange in the encoded protein. Introduction of the mutated allele into a drug susceptible strain resulted in constitutive up-regulation of ERG11 and increased resistance to fluconazole. By comparing the gene expression profiles of the fluconazole resistant isolate and of strains carrying wild-type and mutated UPC2 alleles, we identified target genes that are controlled by Upc2p. Here we show for the first time that a gain-of-function mutation in UPC2 leads to increased expression of ERG11 and imparts resistance to fluconazole in clinical isolates of C. albicans. Keywords: genome-wide expression profiling
2008-11-05 | GSE11320 | GEO
Project description:Two of the major classes of antifungal drugs in clinical use target ergosterol biosynthesis. Despite its importance, our understanding of the transcriptional regulation of ergosterol biosynthesis genes in pathogenic fungi is essentially limited to the role of hypoxia and sterol-stress-induced transcription factors such as Upc2 and Upc2A as well as homologs of sterol response element binding (SREB) factors. To identify additional regulators of ergosterol biosynthesis in Candida glabrata, an important human fungal pathogen with reduced susceptibility to ergosterol biosynthesis inhibitors relative to other Candida spp., we used a serial passaging strategy to isolate suppressors of the fluconazole hypersusceptibility of a upc2AΔ deletion mutant. This led to the identification of loss-of-function mutations in two genes: ROX1, the homolog of a hypoxia gene transcriptional suppressor in Saccharomyces cerevisiae, and CST6, a transcription factor that is involved in the regulation of carbon dioxide response in C. glabrata. Here, we describe a detailed analysis of the genetic interaction of ROX1 and UPC2A. In the presence of fluconazole, loss of Rox1 function restores ERG11 expression to the upc2AΔ mutant and inhibits the expression of ERG3 and ERG6, leading to increased levels of ergosterol and decreased levels of the toxic sterol 14α methyl-ergosta-8,24(28)-dien-3β, 6α-diol, relative to the upc2AΔ mutant. Our observations establish that Rox1 is a negative regulator of ERG gene biosynthesis and indicate that a least one additional positive transcriptional regulator of ERG gene biosynthesis must be present in C. glabrata. IMPORTANCE Candida glabrata is one of the most important human fungal pathogens and has reduced susceptibility to azole-class inhibitors of ergosterol biosynthesis. Although ergosterol is the target of two of the three classes of antifungal drugs, relatively little is known about the regulation of this critical cellular pathway. Sterols are both essential components of the eukaryotic plasma membrane and potential toxins; therefore, sterol homeostasis is critical for cell function. Here, we identified two new negative regulators in C. glabrata of ergosterol (ERG) biosynthesis gene expression. Our results also indicate that in addition to Upc2A, the only known activator of ERG genes, additional positive regulators of this pathway must exist.
| S-EPMC8694151 | biostudies-literature
Project description:In the pathogenic yeast Candida albicans, the zinc cluster transcription factor Upc2p has been shown to regulate expression of ERG11 and other genes involved in ergosterol biosynthesis upon exposure to azole antifungals. ERG11 encodes lanosterol demethylase, the target enzyme of this antifungal class. Over-expression of UPC2 reduces azole susceptibility, whereas its disruption results in hypersusceptibility to azoles and reduced accumulation of exogenous sterols. Constitutive up-regulation of ERG11 is a major cause of resistance to fluconazole in clinical isolates of C. albicans, yet the mechanism for this has yet to be determined. Using genome-wide gene expression profiling, we found UPC2 and other genes involved in ergosterol biosynthesis to be coordinately up-regulated with ERG11 in a fluconazole resistant clinical isolate as compared with a matched susceptible isolate from the same patient. Sequence analysis of the UPC2 alleles of these isolates revealed that the resistant isolate contained a single nucleotide substitution in one UPC2 allele that resulted in a G648D exchange in the encoded protein. Introduction of the mutated allele into a drug susceptible strain resulted in constitutive up-regulation of ERG11 and increased resistance to fluconazole. By comparing the gene expression profiles of the fluconazole resistant isolate and of strains carrying wild-type and mutated UPC2 alleles, we identified target genes that are controlled by Upc2p. Here we show for the first time that a gain-of-function mutation in UPC2 leads to increased expression of ERG11 and imparts resistance to fluconazole in clinical isolates of C. albicans. Keywords: genome-wide expression profiling Clinical isolates S1 (susceptible) and S2 (resistant), genome strain SC5314, UPC2 disruption strains (UPC2M4A and UPC2M4B), UPC2 re-integrant strains of non-mutated UPC2 allele (UPC2M2K21A and UPC2M2K21B), and UPC2 re-integrant strains of mutated UPC2 allele (UPC2M2K31A and UPC2M2K31B) were grown for 3 hours until log phase. RNA was extracted for each isolate/strain. Experiments were performed in duplicate.
2008-11-04 | E-GEOD-11320 | biostudies-arrayexpress
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2025-07-04 | PXD052366 | Pride
Project description:The opportunistic fungal pathogen Cryptococcus neoformans faces a wide range of environmental pH within the host, and adaptation to different pH conditions plays a critical role in their survival and pathogenesis. In the current study, how environmental pH influences antifungal susceptibility and iron uptake in C. neoformans was investigated. We found that acidic pH conditions significantly reduced antifungal susceptibility of C. neoformans to fluconazole. Moreover, our study revealed that iron acquisition in C. neoformans at acidic pH is independent of the high-affinity iron uptake system, and leads to increase of intracellular iron accumulation, increased ergosterol and heme levels, which may contribute to reduced fluconazole susceptibility of the fungus. Transcriptome analysis further elucidated the molecular mechanisms underlying the pH-dependent shift of iron uptake and antifungal susceptibility of C. neoformans. Our findings highlight the importance of environmental pH in physiology and pathogenesis of C. neoformans and provide insights into developing novel treatment for cryptococcosis.
2025-03-18 | GSE291861 | GEO