Functional divergence of a global regulatory complex governing fungal filamentation
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PROVIDER: PRJNA482366 | ENA |
REPOSITORIES: ENA
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Project description:Morphogenetic transitions are prevalent in the fungal kingdom. For a leading human fungal pathogen, Candida albicans, the capacity to transition between yeast and filaments is key for virulence. For the model yeast Saccharomyces cerevisiae, filamentation enables nutrient acquisition. A recent functional genomic screen in S. cerevisiae identified Mfg1 as a regulator of morphogenesis that acts in complex with Flo8 and Mss11 to enable transcriptional responses crucial for filamentation. In C. albicans, Mfg1 also interacts physically with Flo8 and Mss11 and is critical for filamentation in response to diverse cues, but the mechanisms through which it regulates morphogenesis remained elusive. Here, we explored the consequences of perturbation of Mfg1, Flo8, and Mss11 on C. albicans morphogenesis, and identified functional divergence of complex members. We observed that C. albicans Mss11 was dispensable for filamentation, and that overexpression of FLO8 caused constitutive filamentation even in the absence of Mfg1. Epistasis experiments suggested that Mfg1 acts downstream of protein kinase A, as does Flo8. Harnessing transcriptional profiling and chromatin immunoprecipitation coupled to microarray analysis, we identified divergence between transcriptional targets of Mfg1 and Flo8 in C. albicans. A key direct transcriptional target of Mfg1 is TEC1, for which overexpression was sufficient to restore filamentation in the absence of Mfg1. To identify additional Mfg1 downstream effectors, we employed a novel strategy to select for mutations that restore filamentation in the absence of Mfg1. Whole genome sequencing of filamentation-competent mutants revealed chromosome 6 amplification as a conserved adaptive mechanism. A key determinant of the amplification on chromosome 6 is FLO8, as deletion of one allele blocked morphogenesis, and chromosome 6 was not amplified in evolved lineages for which FLO8 was re-located to a different chromosome. Thus, this work highlights rewiring of key morphogenetic regulators over evolutionary time and aneuploidy as an adaptive mechanism driving fungal morphogenesis.
2018-07-24 | GSE117477 | GEO
Project description:Morphogenetic transitions are prevalent in the fungal kingdom. For a leading human fungal pathogen, Candida albicans, the capacity to transition between yeast and filaments is key for virulence. For the model yeast Saccharomyces cerevisiae, filamentation enables nutrient acquisition. A recent functional genomic screen in S. cerevisiae identified Mfg1 as a regulator of morphogenesis that acts in complex with Flo8 and Mss11 to mediate transcriptional responses crucial for filamentation. In C. albicans, Mfg1 also interacts physically with Flo8 and Mss11 and is critical for filamentation in response to diverse cues, but the mechanisms through which it regulates morphogenesis remained elusive. Here, we explored the consequences of perturbation of Mfg1, Flo8, and Mss11 on C. albicans morphogenesis, and identified functional divergence of complex members. We observed that C. albicans Mss11 was dispensable for filamentation, and that overexpression of FLO8 caused constitutive filamentation even in the absence of Mfg1. Harnessing transcriptional profiling and chromatin immunoprecipitation coupled to microarray analysis, we identified divergence between transcriptional targets of Flo8 and Mfg1 in C. albicans. We also established that Flo8 and Mfg1 cooperatively bind to promoters of key regulators of filamentation, including TEC1, for which overexpression was sufficient to restore filamentation in the absence of Flo8 or Mfg1. To further explore the circuitry through which Mfg1 regulates morphogenesis, we employed a novel strategy to select for mutations that restore filamentation in the absence of Mfg1. Whole genome sequencing of filamentation-competent mutants revealed chromosome 6 amplification as a conserved adaptive mechanism. A key determinant of the chromosome 6 amplification is FLO8, as deletion of one allele blocked morphogenesis, and chromosome 6 was not amplified in evolved lineages for which FLO8 was re-located to a different chromosome. Thus, this work highlights rewiring of key morphogenetic regulators over evolutionary time and aneuploidy as an adaptive mechanism driving fungal morphogenesis.
| S-EPMC6336345 | biostudies-literature
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 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:At human body temperature, the fungal pathogen Candida albicans can transition from yeast to filamentous morphologies in response to host-relevant cues. Additionally, elevated temperatures encountered during febrile episodes can independently induce C. albicans filamentation. However, the underlying genetic pathways governing this developmental transition in response to elevated temperature remain largely unexplored. Here, we conducted a functional genomic screen to unravel the genetic mechanisms orchestrating C. albicans filamentation specifically in response to elevated temperature, implicating 45% of genes associated with the spliceosome or pre-mRNA splicing in this process. Employing RNA-Seq to elucidate the relationship between mRNA splicing and filamentation, we identified greater levels of intron retention in filaments compared to yeast, which correlated with reduced expression of the affected genes. Intriguingly, homozygous deletion of a gene encoding a spliceosome component important for filamentation (PRP19) caused even greater levels of intron retention compared with wild-type and globally dysregulated gene expression. This suggests that intron retention is a mechanism for fine-tuning gene expression during filamentation, with perturbations of the spliceosome exacerbating this process and blocking filamentation. Overall, this study unveils a novel biological process governing C. albicans filamentation, providing new insights into the complex regulation of this key virulence trait.
2024-05-28 | GSE262764 | GEO
Project description:The ability of the human pathogenic fungus Candida albicans to switch between yeast-like and filamentous forms of growth has long been linked to pathogenesis. Numerous environmental conditions, including growth at high temperatures, nutrient limitation, and exposure to serum, can trigger this morphological switch and are frequently used in in vitro models to identify genes with roles in filamentation. Previous work has suggested that differences exist between the various in vitro models both in the genetic requirements for filamentation and transcriptional responses to distinct filamentation-inducing media. We compared 10 in vitro models for filamentation and found broad genetic and transcriptomic differences between model systems. Methods: Total RNA was extracted from yeast or filamentous cells grown in liquid media or on solid plates. Samples were tested in biological triplicates. RNASeq libraries were generated beginning with 1.8 ng of total RNA following standardized protocols with the TruSeq RNA v2 kit (Illumina, San Diego). Libraries were diluted to a concentration of 6.0 picomoles and sequenced on a HiSeq2500 and 100 bp single reads were generated. Two lanes were used for each sample.
2017-09-28 | GSE99902 | GEO
Project description:The opportunistic pathogenic fungus Candida albicans can cause devastating infections in severely compromised patients. Its ability to undergo a morphogenetic transition from yeast to filamentous forms allows it to penetrate tissues and cause damage, and the expression of a number of pathogenetic mechanisms are also coordinately regulated with this yeast-to-hyphae conversion. Therefore, it is widely considered that filamentation represents one of the main virulence factors of C. albicans. We have previously identified N-[3-(allyloxy)-phenyl]-4-methoxybenzamide (compound 9029936) as the lead compound in a series of small molecule inhibitors of C. albicans filamentation, and characterized its activity, both in vitro and in vivo, as a promising candidate for the development of alternative anti-virulence strategies for the treatment of C. albicans infections. Here we have performed RNA sequencing analysis of samples obtained from C. albicans cells grown under filament-inducing conditions in the presence or absence of this compound. Overall treatment with compound 9029936 resulted in 618 up-regulated and 702 down-regulated genes. Not surprisingly some of the top down-regulated genes included well characterized genes associated with filamentation and virulence such as SAP5, ECE1 (candidalysin), and ALS3, as well as genes that impact metal chelation and utilization. Gene ontology analysis revealed an over-representation of cell adhesion, iron transport, filamentation, biofilm formation, and pathogenesis processes among down-regulated genes as result of treatment with this leading compound. Interestingly, the top up-regulated genes pointed to an enhancement of vesicular transport pathways, and in particular SNARE interactions.
2019-08-22 | GSE136116 | GEO
Project description:In this study we were interested in studying the role of SAGA subunits in various cellular processes- morphogenetic changes, growth, invasiveness, biofilm formation and to check the role of these subunits under various cellular and genotoxic conditions. In this work, we investigated conditional and null mutants of components of the SAGA complex modules; Ngg1 of the HAT module, Ubp8 of the Dub module, Tra1 of the recruitment module, Spt7 of the architecture module, and Spt8 of the TBP interaction unit to assess their role in processes such as filamentation, invasiveness, and biofilm formation. Spt7 and Spt8 deletion in Candida albicans resulted in ifilamentatation, invasiveness in YPD media at 30 degrees Celsius and also showed sensitivity to antifungal drugs. Wild type SN148 do not make any filaments in YPD at 30 degrees Celsius and didn't show antifungal sensitivity . The aim was to look for transcription profiling of SAGA mutants against wild type to find genes up and down regulated in the mutant especially those ones critical for filamentation, invasiveness and antifungal drug resistance.
2022-03-09 | GSE193907 | GEO
Project description:The regulatory mechanism for filamentation includes a complex network of transcription factors that play roles in regulating hyphae associated genes. We identify here a new regulator of filamentation from the zinc cluster transcription factor family. We present evidence suggesting that this transcription factor assists the Nrg1/Brg1 switch regulating hyphal development.
2020-12-31 | GSE143825 | GEO
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