Differential gene expression in a Cryptococcus neoformans ccr4Delta mutant during host-temperature adaptation
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ABSTRACT: Analysis of ccr4 Delta vs. wild type shifted from 30oC to 37oC for 10 minutes To determine the effect of ccr4 deletion on temperature stress-responsive changes in gene expression in C. neoformans
ORGANISM(S): Cryptococcus neoformans var. neoformans Cryptococcus neoformans
Project description:Analysis of ccr4 Delta vs. wild type shifted from 30oC to 37oC for 10 minutes To determine the effect of ccr4 deletion on temperature stress-responsive changes in gene expression in C. neoformans Replicate cultures of the wild type (Control) and ccr4Delta mutant were grown to mid log phase at 30oC, harvested and resuspended in 37oC pre-warmed medium for 10 minutes. Pooled biological replicate cultures were hybridized in duplicate (2 slides, 2 arrays/slide)
Project description:We measured protein translation (by ribosome profiling) and RNA levels (by polyA-enriched RNA-seq) in Cryptococcus neoformans strain H99 and Cryptococcus neoformans strain JEC21. This is the first transcriptome-wide map of translation in this species complex.
Project description:We investigated the effects of the hypoxia-mimetic CoCl2 on the gene expression of pathogenic fungus Cryptococcus neoformans. Keywords: compound treatment design
Project description:The target of rapamycin (TOR) pathway is an evolutionarily conserved signal transduction system that is activated by varying nutrient and environmental signals and governs a plethora of eukaryotic biological processes. Nevertheless, its role in the human fungal pathogen Cryptococcus neoformans remains elusive. In this study, we investigated the TOR pathway by functionally characterizing two Tor-like kinases, Tor1 and Tlk1, in C. neoformans. We successfully deleted TLK1, but not TOR1. TLK1 deletion did not result in any evident in vitro phenotypes, except for a minor role in diamide and polyene resistance, suggesting that Tlk1 is mainly dispensable for the growth of C. neoformans. We further demonstrated that Tor1, but not Tlk1, is essential and the target of rapamycin by constructing and analyzing conditionally regulated strains and sporulation analysis of heterozygous mutants in the diploid strain background. To analyze the functions of Tor1 in more detail, we constructed constitutive TOR1 overexpression strains. Tor1 negatively regulated thermotolerance and the DNA damage response, which are two important virulence factors of C. neoformans. We also found that TOR1 overexpression reduced Mpk1 phosphorylation, which is required for cell wall integrity and thermoresistance, and Rad53 phosphorylation, which governs the DNA damage response pathway. Tor1 is localized to the cytoplasm but enriched in the vacuole membrane. Phosphoproteomics and transcriptomics revealed that Tor1 regulates a variety of biological processes, including metabolic processes, cytoskeleton organization, ribosome biogenesis, autophagy, and stress response. Finally, screening rapamycin-sensitive and -resistant kinase and transcription factor mutants revealed that the TOR pathway may crosstalk with a number of signaling pathways, including the Hog1 pathway. In conclusion, our study demonstrates that a single Tor1 kinase plays a variety of roles in the fungal meningitis pathogen C. neoformans.
Project description:Cryptococcus neoformans is an invasive human fungal pathogen, which causes pneumonia and meningoencephalitis in both healthy and immunodeficient individuals, resulting 181,100 deaths each year. Studies have demonstrated that copper detoxification machineries play critical functions in modulating C. neoformans fitness and pathogenicity in the host lung tissue. Pulmonary C. neoformans infection provokes the generation of toxic copper bombardment, which in return activate detoxification process in fungal cells. However, the molecular mechanism on how Cu inhibits C. neoformans in proliferation remains unclear. Here, using Cu detoxification gene knockout strains we demonstrated that exogenous Cu ions inhibit cell growth of the metallothionein mutant, which was significantly rescue when supplementing with the ROS scavenger, N-acetylcysteine. To future characterize the molecular mechanism of C. neoformans response to Cu toxicity, we employ iTRAQ with LC-MS/MS analysis, in the presence of exogenous Cu or NAC. Our data showed that an increased Cu level repressed expression of factors involved in protein translation but activates expression of important players in ubiquitin-degradation process. We proposed that the downregulation of protein synthesis and the upregulation of protein degradation were the main strategy of Cu toxicity. The metallothionein mutant showed a higher ubiquitination level under Cu treatment. In addition, MG132 could partially restore the Cu toxicity effect on metallothionein mutant. These results shed new light on the Cu antifungal mechanisms from proteomic profile.
Project description:Light is a universal environmental signal perceived by many organisms, including the fungi in which light regulates both common and unique biological processes depending on the species. We conducted a whole-genome microarray analysis on the basidiomycete fungus Cryptococcus neoformans to identify light-regulated genes.
Project description:Cryptococcus neoformans interactions with murine macrophages are critical for disease. In this project we analyzed fungal proteins which were co-purified with murine host proteins after interaction. H99 C. neoformans was opsonized with mAb 18B7 and addedd to murine macrophages. Then murine cells were lysed and cell extracts submitted to proteomics.