Project description:Aspergillus fumigatus transcription factor AtrR is a critical determinant of the azole resistance phenotype of this organism. AtrR positively regulates expression of a range of genes involved in azole resistance including the ATP-binding cassette transporter-encoding locus abcG1 (cdr1B/abcC) as well as the gene that encodes the enzymatic target of azole drugs cyp51A. Homology searches of A. fumigatus AtrR against a range of fungal species identified highly conserved 25 amino acid region in the carboxy-terminus. To determine the contribution of this region to AtrR function, we prepared a mutant from of the atrR that lacked this region (Δ855-879). We compared the response of an isogenic wild-type strain to a strain expressing the Δ855-879 AtrR derivative using RNA-seq, both in the absence and the presence of voriconazole challenge. The resulting data indicate that this 25 amino acid segment of AtrR is required for expression of some but not all AtrR target genes.
Project description:The Negative cofactor 2 (NCT) complex is an evolutionally conserved heterodimeric transcription factor. In Aspergillus fumigatus, the NCT complex consists of two subunits NctA and NctB. Through a genome-wide screening of a transcription factor null mutant strains, we found that loss of the NCT complex leads to a multi-drug resistance phenotype including the azoles (itraconazole, voriconazole and posaconazole) as well as the salvage therapeutic amphotericin B, and terbinafine. To obtain further insight into the molecular mechanisms driving the azole-resistance in the NCT complex null mutants, we analyzed genome-wide binding profiles of NctA using chromatin-immunoprecipitation sequencing (ChIP-seq). Our ChIP-seq analysis revealed that NCT complex binds the promoters of several ergosterol biosynthetic genes, their transcriptional regulators, and the azole efflux pump cdr1B. Taken together, these results suggest that the NCT complex plays a role as a master regulator of drug resistance in A. fumigatus.
Project description:The Negative cofactor 2 (NCT) complex is an evolutionally conserved heterodimeric transcription factor. In Aspergillus fumigatus, the NCT complex consists of two subunits NctA and NctB. Through a genome-wide screening of a transcription factor null mutant strains, we found that loss of the NCT complex leads to a multi-drug resistance phenotype including the azoles (itraconazole, voriconazole and posaconazole) as well as the salvage therapeutic amphotericin B, and terbinafine. To obtain further insight into the molecular mechanisms driving the azole-resistance in the NCT complex null mutants, we analyzed genome-wide gene expression profiles of the nctA and the nctB null mutants using RNA-seq. Our expression profiling revealed that disruption of the genes lead to upregulation of several ergosterol biosynthetic genes, their transcriptional activators, and the azole efflux pump cdr1B. Taken together, these results suggest that the NCT complex plays a role as a master regulator of drug resistance in A. fumigatus.
Project description:Genome sequence data results are reported from experimental and bioinfomatic work using the technique 'Bulk Segregant Analysis' to determine the genetic basis of observed resistance to the azole antifungal compound itraconazole in the opportunistic fungal pathogen Aspergillus fumigatus.
Project description:The widespread use of azole antifungal drugs in agriculture and clinical settings has led to serious drug resistance issues. Under azole treatment, resistant strains can upregulate the expression of the azole drug target 14α-demethylase ERG11 through transcription factors to alleviate the stress induced by sterol synthesis inhibition, which is a common resistance mechanism. Additionally, the currently reported regulatory factors related to resistance are not sufficient to explain all resistance issues. In this study, we constructed a GFP gene reporter system based on the erg11 promoter in the model filamentous fungus, Neurospora crassa, and identified a key region of the promoter that governs the erg11 response to azole drug by stepwise deletion. Using specific probes for DNA pulldown and combined with phenotype analysis, we identified a protein, Crf4-3, containing a PWWP domain that has a positive regulatory effect. Specific deletion of Crf4-3 leads to hypersensitivity to azole drugs and loss of transcriptional response of erg11 and erg6 to ketoconazole. Furthermore, the basal expression of erg1, erg11, erg25, and erg3A is affected by the deletion of crf4-3. Crf4-3 homologs are widely present in the Pezizomycotina fungi. Deletion of the homologous protein of Crf4-3 in Aspergillus fumigatus also significantly reduced sensitivity to azole drugs like voriconazole by reducing the transcriptional response of erg11. In summary, our study revealed a new regulatory factor Crf4-3 involved in the azole stress response in filamentous fungi and its mechanism, providing new insights into understanding the mechanisms of azole drug resistance.
2024-09-15 | GSE272185 | GEO
Project description:Cyp51A mutaion in Aspergillus fumigatus
| PRJNA625857 | ENA
Project description:Cyp51A sequencing of Aspergillus fumigatus
Project description:The filamentous fungus Aspergillus fumigatus is an opportunistic human pathogen, which can cause mycoses and allergies in susceptible individuals. With regard to therapy, the polyene drug amphotericin B (AmB) is still frequently used to treat Aspergillus fumigatus infections due to the fact that it remains effective against azole-resistant Aspergillus strains. AmB binds to ergosterol in the fungal membrane, but its mode of action and the fungal resistance mechanisms involved have not been completely elucidated yet. To get further insights into the drug mechanisms of AmB, we investigated the proteomic profile of A. fumigatus in response to AmB and its liposomal formulation by LC-MS/MS analysis. A significant increase (≥ 2-fold) in abundance of 202 different proteins in response to AmB and 193 in case of liposomal AmB was observed, while the level of 70 and 83 proteins decreased, respectively. In particular, the level of proteins anchored to the membrane, involved in catabolic processes, aromatic acid degradation, or secondary metabolism increased prominently. Of particular note was the more than 300-fold increase of a RTA1 domain-containing protein after AmB treatment. Fungal RTA-like proteins represent lipid-translocating exporters, which are characterized by multiple transmembrane regions and often confer resistance to toxic chemicals. Indeed, the deletion of the corresponding gene in A. fumigatus led to an increased susceptibility to AmB and other antifungal polyenes such as nystatin. Particularly worthy of mention is that some of the most significantly increased proteins included enzymes involved in the biosynthesis of secondary metabolites such as the prenylated polyphenol fumicycline as well as xanthocillin and hexadehydro-astechrome, which both form complexes with transition metals.
Project description:<p>Aspergillus fumigatus is a notorious opportunistic pathogen that causes Invasive Aspergillosis (IA) infections with high mortality in immunosuppressed individuals. Long-term antifungal drug azole abuse in clinical treatment and agriculture renders it ineffectual or drug resistant. Drug resistance can relate to the cellular metabolites and corresponding gene transcription. In this study, through untargeted metabolomics and transcriptomics following itraconazole (ITC) treatment we identified two plasma membrane-localized polyamine transporters Aftpo3 and Afdur3, which were important for polyamine homeostasis and ITC susceptibility in A. fumigatus. In the absence of Aftpo3 or Afdur3, the levels of cytoplasm polyamines had a moderate increase, accompanied by resistance to ITC. In comparison, overexpression of Aftpo3 or Afdur3 induced drastic increase of polyamines, which were linked with the sensitivity to ITC. Accordingly, our study demonstrated that concentration-dependence of polyamines affected susceptibility of A. fumigatus to ITC, by scavenging reactive oxygen species (ROS) at a moderate concentration or generating ROS at a high concentration rather than drug transport.</p>