SAGA Complex Subunits in Candida albicans Differentially Regulate Filamentation, Invasiveness and Biofilm Formation
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PROVIDER: PRJNA798386 | ENA |
REPOSITORIES: ENA
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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:SAGA (Spt-Ada-Gcn5-acetyltransferase) is a highly conserved, multiprotein co-activator complex that consists of five distinct modules. It has two enzymatic functions, a histone acetyltransferase (HAT) and a deubiquitinase (DUB) and plays a central role in processes such as transcription initiation, elongation, protein stability, and telomere maintenance. We analyzed conditional and null mutants of the SAGA complex module components in the fungal pathogen Candida albicans; Ngg1, (the HAT module); Ubp8, (the DUB module); Tra1, (the recruitment module), Spt7, (the architecture module) and Spt8, (the TBP interaction unit), and assessed their roles in a variety of cellular processes. We observed that spt7Δ/Δ and spt8Δ/Δ strains have a filamentous phenotype, and both are highly invasive in yeast growing conditions as compared to the wild type, while ngg1Δ/Δ and ubp8Δ/Δ are in yeast-locked state and non-invasive in both YPD media and filamentous induced conditions compared to wild type. RNA-sequencing-based transcriptional profiling of SAGA mutants reveals upregulation of hyphal specific genes in spt7Δ/Δ and spt8Δ/Δ strains and downregulation of ergosterol metabolism pathway. As well, spt7Δ/Δ and spt8Δ/Δ confer susceptibility to antifungal drugs, to acidic and alkaline pH, to high temperature, and to osmotic, oxidative, cell wall, and DNA damage stresses, indicating that these proteins are important for genotoxic and cellular stress responses. Despite having similar morphological phenotypes (constitutively filamentous and invasive) spt7 and spt8 mutants displayed variation in nuclear distribution where spt7Δ/Δ cells were frequently binucleate and spt8Δ/Δ cells were consistently mononucleate. We also observed that spt7Δ/Δ and spt8Δ/Δ mutants were quickly engulfed by macrophages compared to ngg1Δ/Δ and ubp8Δ/Δ strains. All these findings suggest that the SAGA complex modules can have contrasting functions where loss of Spt7 or Spt8 enhances filamentation and invasiveness while loss of Ngg1 or Ubp8 blocks these processes.
| S-EPMC8957876 | biostudies-literature
Project description:ChIP-nexus performed in Kc167 cells for subunits of the SAGA coactivator complex;ChIP performed in ovary homogenate for subunits of the SAGA coactivator complex
2021-10-29 | GSE166224 | 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: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: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:Candidiasis affects a wide variety of immunocompromised individuals, including HIV/AIDS patients and cancer patients on chemotherapy. Candida albicans, a major human fungal pathogen, accounts for about 50% of all cases, while the remainder are caused by the less pathogenic non-albicans Candida species (NACS). These species are believed to be less pathogenic, in part, because they do not filament as readily or robustly as C. albicans, although definitive evidence is lacking. To address this question, we used strains for two NACS, Candida tropicalis and Candida parapsilosis, that are genetically engineered to constitutively express the key transcriptional regulator UME6 and drive strong filamentation both in vitro and during infection in vivo. Unexpectedly, both strains showed a dramatic reduction in organ fungal burden and clearance of infection in response to UME6 expression. Consistent with these findings, we observed that a C. tropicalis hyperfilamentous mutant was significantly reduced and a filamentation-defective mutant was slightly increased for organ fungal burden. Comprehensive immune profiling did not reveal any significant changes in the host immune response to UME6 expression in the NACS. Interestingly, however, whole-genome transcriptional profiling indicated that while genes important for filamentation were induced by UME6 expression in C. tropicalis and C. parapsilosis, other genes involved in a variety of processes important for pathogenesis were strongly down-regulated. Our findings are significant because they suggest fundamental evolutionary differences in the relationship between morphology and pathogenicity among Candida species and that NACS do not necessarily possess the same virulence properties as C. albicans.
2019-10-01 | GSE134321 | GEO
Project description:The ability of the fungus Candida albicans to filament and form biofilms contributes to its burden as a leading cause of hospital-acquired infections. Biofilm development involves an interconnected transcriptional regulatory network (TRN) consisting of nine transcription factors (TFs) that bind both to their own regulatory regions and to those of the other network TFs. Here, we show that seven of the nine TFs in the C. albicans biofilm network contain prion-like domains (PrLDs) that have been linked to the ability to form phase-separated condensates. Construction of PrLD mutants in four biofilm TFs reveals that these domains are essential for filamentation and biofilm formation in C. albicans. Moreover, biofilm PrLDs promote the formation of phase-separated condensates in the nuclei of live cells, and PrLD mutations that abolish phase separation (such as the removal of aromatic residues) also prevent biofilm formation. Biofilm TF condensates can selectively recruit other TFs through PrLD-PrLD interactions and can co-recruit RNA polymerase II, implicating condensate formation in the assembly of active transcriptional complexes. Finally, we show that PrLD mutations that block the phase separation of biofilm TFs also prevent filamentation in an in vivo model of gastrointestinal colonization. Together, these studies associate transcriptional condensates with the regulation of filamentation and biofilm formation in C. albicans, and highlight how targeting of PrLD-PrLD interactions could prevent pathogenesis by this species.
2023-11-20 | GSE245897 | 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 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:Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of drug resistance. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1Δ/efg1Δ mutant is non-filamentous, as central signalling pathways linking environmental cues to hypha formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. To investigate the transcriptional response underlying the yeast-to-filament transition in the evolved strain, we applied RNA-Seq technology. Furthermore, RNA-Seq data were used to identify SNPs, which are specific for the evolved strain.
2015-03-31 | GSE56174 | GEO