The zinc cluster transcription factor Rha1 is a positive filamentation regulator in Candida albicans
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ABSTRACT:
ORGANISM(S): Candida albicans
PROVIDER: GSE143825 | GEO | 2020/12/31
REPOSITORIES: GEO
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Project description:Deleting components of the Arp2/3 complex in Candida albicans resulted in a global lack of hyphal specific gene induction. This observation suggests that the failure in hyphal growth of Arp2/3 complex mutants could be a result of failure to activate hyphal specific genes. If the hyphal defect was primarily due to failure to activate gene expression, de-repressing hyphal-specific gene expression by deleting the NRG1 repressor could potentially suppress the defect, as deletion of NRG1 leads to constitutive filamentous growth even in the absence of any hyphal induction signals (Garcia-Sanchez et al., 2005, Kadosh & Johnson, 2005). We therefore created an nrg1Î/Îarp2Î/Î mutant. When grown under non-inducing conditions, nrg1Î/Îarp2Î/Î cells showed the arp2Î/Î mutant morphology of round and swollen cells. When induced for hyphal growth, nrg1Î/Îarp2Î/Î cells also exhibited the arp2Î/Î cell morphology and did not form hyphae even after extended overnight incubation times. To determine if the hyphal-specific genes are de-repressed in the nrg1Î/Îarp2Î/Î mutant, we performed transcript profiling. We compared the nrg1Î/Îarp2Î/Î mutant grown under hyphal conditions to the arp2Î/Î mutant grown under the same conditions (10% serum, 37ï°C, three hours), and found that a significant number of hyphal-specific genes that are normally induced when WT cells are undergoing the yeast to hyphae switch (WT-HY) showed greater expression in the nrg1Î/Îarp2Î/Î mutant compared to arp2Î/Î cells (p-value 4.9x10-9). When we examined the set of NRG1-dependent hyphal-specific genes previously identified (Kadosh & Johnson, 2005), we found that seven of 28 genes (HYR1, SAP5, SAP4, KIP4, ORF19.6079, ALS3 and UME6) showed significantly increased expression (⥠2 fold) in nrg1Î/Îarp2Î/Î cells compared to arp2Î/Î cells, while a further four genes (IHD1, CBP1, ORF19.6705 and ALS10) showed moderately increased expression between 1.5 and 2-fold. Thus, while deleting a transcriptional repressor of the filamentation program leads to de-repression of many hyphal genes, the entire regulated gene set is not de-repressed; this presumably reflects the complex interplay that different transcriptional (co-) repressors exert on the yeast-to-hyphae transition (Garcia-Sanchez et al., 2005, Kadosh & Johnson, 2005). We further found that despite the increased induction of some hyphal genes in the nrg1Î/Îarp2Î/Î mutant, a few of those genes are not as highly induced as in WT cells. One gene that was induced in both the ânrg1Î/Îarp2Î/Î vs arp2Î/Îâ and the ânrg1Î/Îarp2Î/Î vs WTâ-comparisons is UME6, a recently identified key regulator of the hyphal program (Banerjee et al., 2008, Zeidler et al., 2009). Interestingly, although constitutive over-expression of UME6 in WT cells resulted in constitutive filamentous growth even in the absence of hyphae signals (Carlisle et al., 2009), the increased expression level of UME6 in the nrg1Î/Îarp2Î/Î mutant is not sufficient to restore filamentation in the absence of a functional Arp2/3 complex. Thus despite partial de-repression of the hyphal program, hyphae do not form, making it likely other roles of the Arp2/3 complex, such as its function in actin patch formation and actin branching, are required for hyphal development.
2010-01-22 | E-GEOD-19582 | biostudies-arrayexpress
Project description:The yeast-filament transition is essential for the virulence of a variety of fungi that are pathogenic to humans. N-acetylglucosamine (GlcNAc), a ubiquitous molecule in both the environment and host, is one of the most potent inducers of filamentation in Candida albicans and thermally dimorphic fungi such as Histoplasma capsulatum and Blastomyces dermatitidis. However, GlcNAc suppresses rather than promotes filamentation in Candida tropicalis, a fungal species that is closely related to C. albicans. Furthermore, we discover that glucose induces filamentous growth in C. tropicalis. Mutation and overexpression assays demonstrate that the conserved cAMP signaling pathway plays a central role in the regulation of filamentation in C. tropicalis. Activation of this pathway promotes filamentation in C. tropicalis, while inactivation of this pathway results in a serious growth defect in filamentation. By screening an overexpression library of 154 transcription factors, we have identified approximately 40 regulators of filamentous growth in C. tropicalis. Although most of the regulators (e.g., Tec1, Gat2, Nrg1, Sfl1, Sfl2, and Ash1) demonstrate a conserved role in the regulation of filamentation, similar to their homologs in C. albicans or S. cerevisiae, some of them are specific to C. tropicalis. For example, Czf1 and Efh1 repress filamentation, while Wor1, Zcf3, and Hcm1 promote filamentation in C. tropicalis. Bcr1, Aaf1, and Csr1 play a specific role in the process of GlcNAc-regulated filamentation. Our findings indicate that multiple interconnected signaling pathways are involved in the regulation of filamentation in C. tropicalis. These mechanisms have conserved and divergent features among different Candida species. Total RNA profiles of cells grown in Lee's glucose or Lee's GlcNAc medium.
2016-07-01 | E-GEOD-73340 | biostudies-arrayexpress
Project description:Clinical isolates of the human fungal pathogen Candida albicans show significant variation in their ability to undergo in vitro filamentation. In this study, we show that Nrg1, a key repressor of filamentation and filament specific gene expression in standard laboratory strain, has strain dependent functions, especially during infection.
2024-01-20 | GSE253732 | GEO
Project description:Candida albicans is an opportunist pathogen responsible for a large spectrum of infections, from superficial mycosis to systemic diseases known as candidiasis. C. albicans can grow in various morphological forms, including unicellular budding yeasts, filamentous pseudophyphae and true hyphae, and the ability to switch from yeast to hyphal forms is a key survival mechanism in the adaptation of the pathogen to the microenvironments encountered within the host. The filamentation is regulated by multiple signalling pathways and can be induced, in vitro, in several growth media, often leading to contradictory results in the literature. In this study, we use quantitative proteomic analyses to compare the response of C. albicans yeast cells grown in the minimal medium YNB to four media widely used in the literature to induce the yeast to hyphae transition: YNB-Serum, YNB-N-Acetyl-glucosamine (YNB-NAG), Lee medium and the rich Spider medium. We show here that each growth medium induces a unique pattern of response in C. albicans cells, and that some conditions trigger an original and specific metabolic adaptive response. Moreover, comparison of the proteomic profiles indicates modifications of the thiol-dependent oxidative stress status of the cells, especially in YNB-Serum and Lee medium, and, to a lesser extent, in Spider medium, confirming the role of oxidative stress in the filamentation process. Overall, our data indicate that some hypha-inducing media routinely used in the literature are associated with significant changes in in proteomic signature and that should be more often taken account when exploring the filamentation process of the pathogen.
2024-10-31 | PXD052475 | Pride
Project description:The yeast-filament transition is essential for the virulence of a variety of fungi that are pathogenic to humans. N-acetylglucosamine (GlcNAc), a ubiquitous molecule in both the environment and host, is one of the most potent inducers of filamentation in Candida albicans and thermally dimorphic fungi such as Histoplasma capsulatum and Blastomyces dermatitidis. However, GlcNAc suppresses rather than promotes filamentation in Candida tropicalis, a fungal species that is closely related to C. albicans. Furthermore, we discover that glucose induces filamentous growth in C. tropicalis. Mutation and overexpression assays demonstrate that the conserved cAMP signaling pathway plays a central role in the regulation of filamentation in C. tropicalis. Activation of this pathway promotes filamentation in C. tropicalis, while inactivation of this pathway results in a serious growth defect in filamentation. By screening an overexpression library of 154 transcription factors, we have identified approximately 40 regulators of filamentous growth in C. tropicalis. Although most of the regulators (e.g., Tec1, Gat2, Nrg1, Sfl1, Sfl2, and Ash1) demonstrate a conserved role in the regulation of filamentation, similar to their homologs in C. albicans or S. cerevisiae, some of them are specific to C. tropicalis. For example, Czf1 and Efh1 repress filamentation, while Wor1, Zcf3, and Hcm1 promote filamentation in C. tropicalis. Bcr1, Aaf1, and Csr1 play a specific role in the process of GlcNAc-regulated filamentation. Our findings indicate that multiple interconnected signaling pathways are involved in the regulation of filamentation in C. tropicalis. These mechanisms have conserved and divergent features among different Candida species.
2016-07-01 | GSE73340 | GEO
Project description:The zinc cluster transcription factor Rha1 is a positive filamentation regulator in Candida albicans
| PRJNA601775 | ENA
Project description:Deleting components of the Arp2/3 complex in Candida albicans resulted in a global lack of hyphal specific gene induction. This observation suggests that the failure in hyphal growth of Arp2/3 complex mutants could be a result of failure to activate hyphal specific genes. If the hyphal defect was primarily due to failure to activate gene expression, de-repressing hyphal-specific gene expression by deleting the NRG1 repressor could potentially suppress the defect, as deletion of NRG1 leads to constitutive filamentous growth even in the absence of any hyphal induction signals (Garcia-Sanchez et al., 2005, Kadosh & Johnson, 2005). We therefore created an nrg1Δ/Δarp2Δ/Δ mutant. When grown under non-inducing conditions, nrg1Δ/Δarp2Δ/Δ cells showed the arp2Δ/Δ mutant morphology of round and swollen cells. When induced for hyphal growth, nrg1Δ/Δarp2Δ/Δ cells also exhibited the arp2Δ/Δ cell morphology and did not form hyphae even after extended overnight incubation times.
2010-01-23 | GSE19582 | GEO
Project description:Candida albicans is an opportunist pathogen responsible for a large spectrum of infections, from superficial mycosis to the systemic disease candidiasis. Its ability to adopt various morphological forms, such as unicellular yeasts, filamentous pseudohyphae and hyphae, contributes to its ability to survive within the host. It has been suggested that the antioxidant glutathione is involved in the filamentation process. We investigated S-glutathionylation, the reversible binding of glutathione to proteins, and the functional consequences on C. albicans metabolic remodeling during the yeast-to-hyphae transition. Our work provided evidence for the specific glutathionylation of mitochondrial proteins involved in bioenergetics pathways in filamentous forms and a regulation of the main enzyme of the glyoxylate cycle, isocitrate lyase, by glutathionylation. Our proteomic data demonstrate that the binding of one glutathione molecule to isocitrate lyase in the hyphal forms leads to enzyme inactivation which was reversed by glutaredoxin treatment. We also assessed the effect of alternative carbon sources on glutathione levels and isocitrate lyase activity. Changes in nutrient availability led to morphological flexibility and was related to perturbations in glutathione levels and isocitrate lyase activity, confirming the key role of the maintenance of intracellular redox status in the adaptive metabolic strategy of the pathogen.
2016-04-21 | PXD003685 | Pride
Project description:Goal of this study was to determine metabolic adaptation processes in C. albicans associated to hyphal morphogenesis. Accessory to the metabolic profiling the corresponding transcriptome was investigated. To identify media-specific and general adaptation three different hyphae stimuli were used (M199 pH 7.4, Human serum and N-Aectylglucosamine) were used and compared again two respective yeast conditions (SD and M199 pH 4). Two filamentation-affected mutant strains were included - lacking either two central regulators of filamentation (cph1Δ/efg1Δ) or a downstream effector (hgc1Δ) - for the identification of specfic morphotype-dependent metabolic adaptation in repsonse to hyphae stimuli. Two different time points (90 min and 240 min after transition to test medium) were investigated to define the progression of the examined adaptation processes.
2022-10-14 | GSE202941 | GEO
Project description:Zinc cluster transcription factors (TFs) are essential fungal regulators of gene expression. In the pathogen Candida albicans, the gene orf19.1604 encodes a zinc cluster TF regulating filament development. Hyperactivation of orf19.1604, which we have named RHA1 for Regulator of Hyphal Activity, generates wrinkled colony morphology under nonhyphal growth conditions, triggers filament formation, invasiveness, and enhanced biofilm formation and causes reduced virulence in the mouse model of systemic infection. The strain expressing activated Rha1 shows up-regulation of genes required for filamentation and cell-wall-adhesion-related proteins. Increased expression is also seen for the hyphal-inducing TFs Brg1 and Ume6, while the hyphal repressor Nrg1 is downregulated. Inactivation of RHA1 reduces filamentation under a variety of filament-inducing conditions. In contrast to the partial effect of either single mutant, the double rha1 ume6 mutant strain is highly defective in both serum- and Spider-medium-stimulated hyphal development. While the loss of Brg1 function blocks serum-stimulated hyphal development, this block can be significantly bypassed by Rha1 hyperactivity, and the combination of Rha1 hyperactivity and serum addition can generate significant polarization even in brg1 ume6 double mutants. Thus, in response to external signals, Rha1 functions with other morphogenesis regulators including Brg1 and Ume6, to mediate filamentation.
| S-EPMC8733637 | biostudies-literature