Project description:Comparison of transcriptional profiles of WT Cryptococcus neoformans (H99) and strain CM126 (pRPL2b-GAT201) which overexpresses the transcription factor GAT201 using a ribosomal protein promoter Keywords: Genetic modification
Project description:The ability to sense and adapt to a hostile host environment is a crucial element for virulence of pathogenic fungi, including Cryptococcus neoformans. These cellular responses are evoked by diverse signaling cascades, including the stress-activated HOG pathway. Despite previous analysis of central components of the HOG pathway, its downstream signaling network is poorly characterized in C. neoformans. Here we performed comparative transcriptome analysis with HOG signaling mutants to explore stress-regulated genes and their correlation with the HOG pathway in C. neoformans. In this study we not only provide important insights into remodeling patterns of global gene expression for counteracting external stresses, but also elucidated novel characteristics of the HOG pathway in C. neoformans. First, inhibition of the HOG pathway increases expression of ergosterol biosynthesis genes and cellular ergosterol content, conferring a striking synergistic antifungal activity with amphotericin B and providing an excellent opportunity to develop a novel therapeutic method for treatment of cryptococcosis. Second, a number of cadmium-sensitive genes are differentially regulated by the HOG pathway, and their mutation causes resistance to cadmium. Finally, we have discovered novel stress-defense and HOG-dependent genes, which encodes a sodium/potassium efflux pump, protein kinase, multidrug transporter system, and elements of the ubiquitin-dependent system.
Project description:The bZIP transcription factor Atf1 governs the oxidative stress response and sexual differentiation of Cryptococcus neoformans downstream of the HOG pathway
Project description:The ability to sense and adapt to a hostile host environment is a crucial element for virulence of pathogenic fungi, including Cryptococcus neoformans. These cellular responses are evoked by diverse signaling cascades, including the stress-activated HOG pathway. Despite previous analysis of central components of the HOG pathway, its downstream signaling network is poorly characterized in C. neoformans. Here we performed comparative transcriptome analysis with HOG signaling mutants to explore stress-regulated genes and their correlation with the HOG pathway in C. neoformans. In this study we not only provide important insights into remodeling patterns of global gene expression for counteracting external stresses, but also elucidated novel characteristics of the HOG pathway in C. neoformans. First, inhibition of the HOG pathway increases expression of ergosterol biosynthesis genes and cellular ergosterol content, conferring a striking synergistic antifungal activity with amphotericin B and providing an excellent opportunity to develop a novel therapeutic method for treatment of cryptococcosis. Second, a number of cadmium-sensitive genes are differentially regulated by the HOG pathway, and their mutation causes resistance to cadmium. Finally, we have discovered novel stress-defense and HOG-dependent genes, which encodes a sodium/potassium efflux pump, protein kinase, multidrug transporter system, and elements of the ubiquitin-dependent system. There is more than 95% genome homology between JEC21 (Cryptococcus neoformans var. neoformans serotype D) and H99 (Cryptococcus neoformans var. grubii serotype A). Therefore, 100 slides of JEC21 70-mer oligo arrays are used in this analysis. 3 biological replicate experiments are performed. Total RNAs are extracted under 3 conditions (1M NaCl, 20ug/ul Fludioxonil, 2.5mM Hydrogen peroxide) at 3 time points (0time, 30min, 60min) with 4 strains from H99 (wild type, hog1Î , ssk1Î , skn7Î). We use a mix of all the total RNAs from this experiment as the control RNA. We use Cy5 as the sample dye and Cy3 as the control dye. Several samples are dye swapped.
Project description:Comparison of transcriptional profiles of WT Cryptococcus neoformans (H99) and strain CM126 (pRPL2b-GAT201) which overexpresses the transcription factor GAT201 using a ribosomal protein promoter Keywords: Genetic modification WT vs. CM126 competitive hybridization. 4 biological replicates including 2 dye flips. Cultures grown at 37 degress Celsius in minimal (YNB) medium. Cultures independently grown and harvested during exponential growth.
Project description:To identify the genome-wide transcriptional changes that occur throughout germination of C. neoformans spores, we conducted a time-course microarray experiment spanning six timepoints to generate a temporal expression pattern for each known gene. Spores were placed in rich medium and allowed to germinate for 10 hours, when they start to replicate as yeast. Each time point was flash frozen in liquid nitrogen and RNA was harvested for each time point at the same time. Microarray hybridizations were conducted in a reference pool design, where each time point was mixed together in equal amounts to make a reference pool sample. Then each time point was hybrdized against the reference pool. Characterization of the genes and pathways that are regulated during germination of this ubiquitous fungal pathogen will allow us to better understand how infectious spores resume vegetative growth, a process that likely is critical for interaction between C. neoformans and a host.
