Opaque filamentation in Low Phosphate (LP) and Sorbitol (SOR) compared to in SCD
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ABSTRACT: Act1-Wor1 strain (the opaque strain CAY2903 with constitute WOR1 expression), wildtype white (a/a RBY717); Opaque hyphal formation in liquid LP and SOR compared to SCD; white cells in the same conditions as control. 6 condition experiment: opaque and white cells in LP, SOR and SCD. Used the pool of all conditions as reference.
Project description:Act1-Wor1 strain (the opaque strain CAY2903 with constitute WOR1 expression), wildtype white (a/a RBY717); Opaque hyphal formation in liquid LP and SOR compared to SCD; white cells in the same conditions as control.
Project description:Transcriptional profiling of C. tropicalis a/alpha cells (CAY1511) in white state, opaque state, overexpressing Wor1, or wor1 mutants hybridized against a universal mixed reference sample from all 4 states. 4 condition experiment: white, opaque, tdh3-wor1, Δ/Δwor1; 4 biological replicates of each
Project description:Transcriptional profiling of C. tropicalis a cells (CAY1503) in opaque state and overexpressing Wor1 in biofilms hybridized against a universal mixed reference sample of a cells in white and opaque states grown in Spider liquid. 2 condition experiment: opaque, tdh3-wor1; 2 biological replicates of each
Project description:Transcriptional profiling of a-type wor1 deleted cells and mixed a-type and alpha-type opaque cells under in vitro biofilm-forming conditions. Specifically, they were grown for two days at room temperature in a 12-well poly-styrene plate containing 1 ml of Lee's + Glucose liquid media. Samples were hybridized against a universal mixed reference sample of a-type cells in white and opaque states grown in Spider liquid media. 2 condition experiment: white wor1-deletion mutant a-type cells, opaque mixed a-type and alpha-type cells; two biological replicates each.
Project description:Sexual reproduction can promote genetic diversity in eukaryotes, and yet many pathogenic fungi have been labeled as obligate asexual species. It is becoming increasingly clear, however, that cryptic sexual programs may exist in some species, and that efficient mating requires the necessary developmental switch to be triggered. In this study we investigate Candida tropicalis, an important human fungal pathogen that has been reported to be asexual. Significantly, we demonstrate that C. tropicalis uses a phenotypic switch to regulate a cryptic program of sexual mating. Thus, diploid a and α cells must undergo a developmental transition to the mating-competent form, and only then does efficient cell-cell conjugation take place resulting in the formation of stable a/α tetraploids. We show that both the phenotypic switch and sexual mating depend on the conserved transcriptional regulator Wor1, which is regulated by temperature in other fungal species. In contrast, C. tropicalis mating occurs efficiently at both 25 °C and 37 °C, suggesting that it could occur in the mammalian host and have direct consequences for the outcome of an infection. Transcriptional profiling further reveals that ≈400 genes are differentially expressed between the two phenotypic states, including the regulatory factor Wor1. Taken together, our results demonstrate that C. tropicalis has a unique sexual program, and that entry to this program is controlled via a Wor1-mediated, metastable switch. These observations have direct implications for the regulation and evolution of cryptic sexual programs in related fungal pathogens. 4 biological replicates of both the white (CAY1504) and opaque (CAY2275) states of C. tropicalis a cells are included on this array. All are hybridized against a universal reference sample, which consists of the combined RNA from all 8 replicates used on this array.
Project description:Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced - under a specialized set of conditions - to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such "pheromone-stimulated" biofilms with that of "conventional" C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 206 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former. 4 condition experiment: white and opaque cells in planktonic and pheromone-induced biofilm conditions with and without alpha pheromone. WT strain (P37005), the tec1 mutant strain and the cph1 mutant strain
Project description:Transcriptional profiling of C. tropicalis a/alpha cells (CAY1511) in white state, opaque state, overexpressing Wor1, or wor1 mutants hybridized against a universal mixed reference sample from all 4 states.
Project description:This experiment is a characterization of the commitment point of the temperature induced opaque-to-white switch in the fungal pathogen Candida albicans. This experiment examines changes in the transcriptome occurring at the 50% commitment points for both the wild type and WOR1/wor1 strains in order to distinguish between changes related to commitment and experimental artifacts, thus identifying transcriptome changes reflective of commitment. These two strains have different 50% commitment points [2hr45min for WOR1/wor1, 5hr10min for wild type]. All collapsed and combined data files submitted for this experiment can be found on the ArrayExpress ftp site in the archive E-MEXP-2834.additional.zip.
Project description:The human pathogen Candida albicans can assume either of two distinct cell types, designated ‘‘white’’ and ‘‘opaque.’’ Each cell type is maintained for many generations; switching between them is rare and stochastic, and occurs without any known changes in the nucleotide sequence of the genome. The two cell types differ dramatically in cell shape, colony appearance, mating competence, and virulence properties. In this work, we investigate the transcriptional circuitry that specifies the two cell types and controls the switching between them. First, we identify two new transcriptional regulators of white-opaque switching, Czf1 and white-opaque regulator 2 (Wor2). Analysis of a large set of double mutants and ectopic expression strains revealed genetic relationships between CZF1, WOR2, and two previously identified regulators of white-opaque switching, WOR1 and EFG1. Using chromatin immunoprecipitation, we show that Wor1 binds the intergenic regions upstream of the genes encoding three additional transcriptional regulators of white-opaque switching (CZF1, EFG1, and WOR2), and also occupies the promoters of numerous white- and opaque-enriched genes. Based on these interactions, we have placed these four genes in a circuit controlling white-opaque switching whose topology is a network of positive feedback loops, with the master regulator gene WOR1 occupying a central position. Our observations indicate that a key role of the interlocking feedback loop network is to stably maintain each epigenetic state through many cell divisions. Keywords: ChIP-chip
Project description:Transcriptional profiling of C. tropicalis a cells (CAY1503) in opaque state and overexpressing Wor1 in biofilms hybridized against a universal mixed reference sample of a cells in white and opaque states grown in Spider liquid.