RNA abundance in wild-type and rtt109 -/- Candida albicans, with and without peroxide stress
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ABSTRACT:
ORGANISM(S): Candida albicans
PROVIDER: GSE18936 | GEO | 2010/01/04
SECONDARY ACCESSION(S): PRJNA121051
REPOSITORIES: GEO
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Project description:Candida albicans is a ubiquitous opportunistic pathogen that is the most prevalent cause of hospital-acquired fungal infections. In mammalian hosts, C. albicans is engulfed by phagocytes that attack the pathogen with DNA-damaging reactive oxygen species (ROS). Acetylation of histone H3 lysine 56 (H3K56) by the fungal-specific histone acetyltransferase Rtt109 is important for yeast model organisms to survive DNA damage and maintain genome integrity. To assess the importance of Rtt109 for C. albicans pathogenicity, we deleted the predicted homologue of Rtt109 in the clinical C. albicans isolate, SC5314. C. albicans rtt109 -/- mutant cells lack acetylated H3K56 (H3K56ac) and are hypersensitive to genotoxic agents. Additionally, rtt109 -/- mutant cells constitutively display increased H2A S129 phosphorylation and elevated DNA repair gene expression, consistent with endogenous DNA damage. Four independent pairs of biological replicate samples were analyzed to compare RNA levels in wild-type and rtt109 -/- cells. Two experiments were performed: first, in unperturbed cells grown in YPD and second, in cells exposed to H2O2. To account for dye effects, two of the four samples for each experiment were analyzed using Cy3 labeling of the wild-type sample and Cy5 labeling of the mutant sample; the dyes were swapped for the other two biological replicates.
2010-05-16 | E-GEOD-18936 | biostudies-arrayexpress
Project description:Acetylation of histone H3 lysine 56 is a covalent modification best-known as a mark of newly-replicated chromatin, but has also been linked to replication-independent histone replacement. Here, we measured H3K56ac levels at single-nucleosome resolution in asynchronously growing yeast cultures, as well as in yeast proceeding synchronously through the cell cycle. We developed a quantitative model of H3K56ac kinetics, which shows that H3K56ac is largely explained by the genomic replication timing and the turnover rate of each nucleosome, suggesting that cell cycle profiles of H3K56ac should reveal most first-time nucleosome incorporation events. However, since the deacetylases Hst3/4 prevent use of H3K56ac as a marker for histone deposition during M phase, we also directly measured M phase histone replacement rates. We report a global decrease in turnover rates during M phase, and a further specific decrease in turnover among early origins of replication, which switch from rapidly-replaced in G1 phase to stable-bound during M phase. Finally, by measuring H3 replacement in yeast deleted for the H3K56 acetyltransferase Rtt109 and its two co-chaperones Asf1 and Vps75, we find evidence that Rtt109 and Asf1 preferentially enhance histone replacement at rapidly-replaced nucleosomes, whereas Vps75 appears to inhibit histone turnover at those loci. These results provide a broad perspective on histone replacement/incorporation throughout the cell cycle, and suggest that H3K56 acetylation provides a positive feedback loop by which replacement of a nucleosome enhances subsequent replacement at the same location.
2008-10-04 | GSE12822 | GEO
Project description:Invasion of host tissue by the human fungal pathogen, Candida albicans is an important step during many forms of candidosis. However, not all C. albicans strains possess the same invasive and virulence properties. It is known for example that the two clinical isolates SC5314 and ATCC10231 differ in their ability to invade into host tissue and to cause infections. Strain SC5314 is invasive whereas strain ATCC10231 is non-invasive and strongly attenuated in virulence as compared to SC5314. In this study we compare the in vitro transcriptional profiles and the genotypic profiles of these two widely used laboratory strains in order to determine the principal biological and genetic properties which may govern the different potential for invasiveness and virulence. Keywords: transcriptional profiling, comparative genomic hybridisation, invasive vs. non-invasive C. albicans strain Genomic DNA from C. albicans strains SC5314 and ATCC10231 hybridisations were done in duplicate including one dye swap. Total RNA from C. albicans strains SC5314 and ATCC10231 strains were compared in triplicate including one biological replicate and one dye swap.
2010-05-26 | E-GEOD-10689 | biostudies-arrayexpress
Project description:Invasion of host tissue by the human fungal pathogen, Candida albicans is an important step during many forms of candidosis. However, not all C. albicans strains possess the same invasive and virulence properties. It is known for example that the two clinical isolates SC5314 and ATCC10231 differ in their ability to invade into host tissue and to cause infections. Strain SC5314 is invasive whereas strain ATCC10231 is non-invasive and strongly attenuated in virulence as compared to SC5314. In this study we compare the in vitro transcriptional profiles and the genotypic profiles of these two widely used laboratory strains in order to determine the principal biological and genetic properties which may govern the different potential for invasiveness and virulence. Keywords: transcriptional profiling, comparative genomic hybridisation, invasive vs. non-invasive C. albicans strain
2008-03-11 | GSE10689 | GEO
Project description:The fungal pathogen Candida albicans produces dark-pigmented melanin when grown in a basal medium containing 1 mM l-DOPA as melanin substrate. In the widely used C. albicans strain SC5314, melanin appeared after 3-4 days of incubation in l-DOPA medium. The experiment was designed to reveal cadidate genes associated with melanin biosynthesis by expression profiling at different times of growth with and without L-DOPA added to the medium. Expression profiling of C. albicans revealed very few genes significantly up- or down-regulated by growth in l-DOPA.
2010-07-07 | GSE20338 | GEO
Project description:Candida spp. represent the third most frequent worldwide cause of infection in Intensive Care Units (ICUs) with a mortality rate of almost 40%. The classes of antifungals currently available include azoles, polyenes, echinocandins, pyrimidine derivatives, and allylamines. However, the therapeutical options for the treatment of candidiasis are drastically reduced by the increasing antifungal resistance. The growing need of a more targeted antifungal therapy is limited by the concern of finding molecules that specifically recognize the microbial cell without damaging the host. Epigenetic writers and erasers have emerged as promising targets in different contexts, including the treatment of fungal infections. In C. albicans, Hst3p, a sirtuin that deacetylates histone H3K56ac, represents an attractive antifungal target as it is essential for the fungus viability and virulence. Although the relevance of such epigenetic regulator is documented for the development of new antifungal therapies, the molecular mechanism behind Hst3p-mediated epigenetic regulation remains unrevealed. Here, we provide the first genome-wide profiling of H3K56ac in C. albicans; H3K56ac enriched regions are associated with Candida sp. pathogenicity. Upon Hst3p inhibition, 447 regions gain H3K56ac. Importantly, these genomic areas contain genes encoding for adhesin proteins, degradative enzymes, and white-opaque switch. Moreover, our RNA-seq analysis revealed 1330 upregulated and 1081 downregulated transcripts upon Hst3p inhibition, and among them, 87 genes whose transcription upregulation correlates well with changes in promoter H3K56 acetylation, including some well-known regulators of phenotypic switching and virulence, confirming that Hst3p is an appealing target for the development of new potential antifungal target.
2023-02-04 | E-MTAB-12167 | biostudies-arrayexpress
Project description:Candida albicans is a diploid human fungal pathogen that displays significant genomic and phenotypic heterogeneity over a range of virulence traits and in the context of a variety of environmental niches. Here, we show that the effects of Rob1 on biofilm and filamentation virulence traits is dependent on both the specific environmental condition and the clinical strain of C. albicans. The C. albicans reference strain SC5314 is a ROB1 heterozygote with two alleles that differ by a single nucleotide polymorphism at position 946 resulting in a serine or proline containing isoform. An analysis of 224 sequenced C. albicans genomes indicates that SC5314 is the only ROB1 heterozygote documented to date and that the dominant allele contains a proline at position 946. Remarkably, the ROB1 alleles are functionally distinct and the rare ROB1946S allele supports increased filamentation in vitro and increased biofilm formation in vitro and in vivo, suggesting it is a phenotypic gain-of-function allele. SC5314 is amongst the most highly filamentous and invasive strains characterized to date. Introduction of the ROB1946S allele into a poorly filamenting clinical isolate increases filamentation and conversion of an SC5314 laboratory strain to a ROB1946S homozygote increases in vitro filamentation and biofilm formation. In a mouse model of oropharyngeal infection, the predominant ROB1946P allele establishes a commensal state while the ROB1946S phenocopies the parent strain and invades into the mucosae. These observations provide an explanation for the distinct phenotypes of SC5314 and highlight the role of heterozygosity as a driver of C. albicans phenotypic heterogeneity.
2023-07-29 | GSE238051 | GEO
Project description:Acetylation of histone H3 lysine 56 is a covalent modification best-known as a mark of newly-replicated chromatin, but has also been linked to replication-independent histone replacement. Here, we measured H3K56ac levels at single-nucleosome resolution in asynchronously growing yeast cultures, as well as in yeast proceeding synchronously through the cell cycle. We developed a quantitative model of H3K56ac kinetics, which shows that H3K56ac is largely explained by the genomic replication timing and the turnover rate of each nucleosome, suggesting that cell cycle profiles of H3K56ac should reveal most first-time nucleosome incorporation events. However, since the deacetylases Hst3/4 prevent use of H3K56ac as a marker for histone deposition during M phase, we also directly measured M phase histone replacement rates. We report a global decrease in turnover rates during M phase, and a further specific decrease in turnover among early origins of replication, which switch from rapidly-replaced in G1 phase to stable-bound during M phase. Finally, by measuring H3 replacement in yeast deleted for the H3K56 acetyltransferase Rtt109 and its two co-chaperones Asf1 and Vps75, we find evidence that Rtt109 and Asf1 preferentially enhance histone replacement at rapidly-replaced nucleosomes, whereas Vps75 appears to inhibit histone turnover at those loci. These results provide a broad perspective on histone replacement/incorporation throughout the cell cycle, and suggest that H3K56 acetylation provides a positive feedback loop by which replacement of a nucleosome enhances subsequent replacement at the same location. To characterize incorporation of H3K56ac in yeast, several sets of ChIP-chip experiments were performed, along with a set of gene expression microarrays. The following describes each individual set, the number of biological and array replicates performed, dye-flip replicates if performed, the total number of arrays, and the applicable figures in the manuscript. Except for Item D (gene expression), all arrays were ChIP-chip experiments. A. Mid-log H3K56ac measurement. 3 biological replicates, 1 array replicate each of K56Ac ChIP with Grunstein Lab antibody. 2 biological replicates, 2 array replicates each of K56Ac ChIP with Upstate antibody. 7 total arrays. Figure 1A-C, 3, S1, S2A, S6, S7. B. Cell cycle - H3K56ac measurements. 1 biological replicate, 3 array replicates each of K56Ac ChIP with Upstate antibody. 17 time points (10 min. unavailable in third array replicate). 50 total arrays. Figures 2, 3, 4, S4, S5, S7, S8. C. G1 phase turnover. 1 biological replicate (3 time points) with 1 dye-flip replicate each time point (45 minutes replaced with 60 minutes for dye-flip replicate). 6 total arrays. Tables S2, S3. D. Cell cycle - mRNA measurements. 2 biological replicates, 1 array replicate each. 34 total arrays. Figure S3. E. M phase turnover rates. 2 biological replicates, second biological replicate has one dye-flip replicate. 17 total arrays. Figure 5. F. Deletion mutants in H3K56ac pathway for G1-arrested cells. Strains: wild-type parental strain (PKY4212; 2 biological replicates), asf1D (strain 2 biological replicates), vps75D (3 biological replicates, third biological replicate having two array replicates), rtt109D (2 biological replicates, each with one dye-flip replicate). 12 total arrays. Figure 6.
2008-10-03 | E-GEOD-12822 | biostudies-arrayexpress
Project description:In C. albicans the sirtuin Hst3p is responsible for removing the acetyl group of the Lys 56 of the H3 histone which is particularly abundant in yeasts and contributes to fungal genome integrity and virulence. Here we identified the H3K56ac patterns across Candida albicans genome in cells maintained for 28 h in YPD at 25°C in the presence or absence of 10 mM nicotinamide (used in this study as Hst3p inhibitor). Chromatin immunoprecipitation was carried out using an anti-H3K56ac antibody, whereas input samples were taken before addition the antibody. Two biological replicates were performed for each condition.
2022-10-31 | E-MTAB-12193 | biostudies-arrayexpress
Project description:The fungal pathogen Candida albicans produces dark-pigmented melanin when grown in a basal medium containing 1 mM l-DOPA as melanin substrate. In the widely used C. albicans strain SC5314, melanin appeared after 3-4 days of incubation in l-DOPA medium. The experiment was designed to reveal cadidate genes associated with melanin biosynthesis by expression profiling at different times of growth with and without L-DOPA added to the medium. Expression profiling of C. albicans revealed very few genes significantly up- or down-regulated by growth in l-DOPA. Sixteen paired samples were submitted to dual channel analysis. Four biological replicate samples of RNA were prepared from cells of C. albicans strain SC5314 at four time points, from cultures grown with and without addition of 1 mM L-DOPA, thus generating an initial total of 32 samples for analysis: four experimental and four control samples made after 6 h, 24 h, 48 h and 72 h of growth. For each time point the control (no L-DOPA) samples were pooled and labelled with Cy3-dUTP by reverse transcription. The four individual biological replicates for each time point were separately labelled with Cy5-dUTP by reverse transcription and independently hybridized against the pooled controls on the microarray chips. Results were read with a ScanArray 4000 Microarray Analysis System.
2010-07-07 | E-GEOD-20338 | biostudies-arrayexpress