Project description:Coccidioides is a dimorphic, pathogenic fungus responsible for transmission of the mammalian disease colloquially known as “Valley fever”. To better understand the molecular basis of Coccidioides pathogenesis, previous studies have characterized transcriptomes that define transitions between the saprobic and pathogenic life stages of the two species that cause Valley fever - Coccidioides immitis and Coccidioides posadasii. However, none of these studies have focused on small RNA profiles, which have been shown in several pathogenic fungi to play crucial roles in host-pathogen communication, affecting virulence and infectivity. In this study, we analyzed changes in small RNA expression across three major morphologies of C. posadasii: arthroconidia, mycelia, and spherules, from both intracellular and extracellular fractions. Utilizing RiboMarker® small RNA and RNA fragment library preparation, we show enhanced coverage across the transcriptome by increasing incorporation of normally incompatible RNAs into the sequencing pool. Using these data, we observed transcriptomic shifts during the transition of arthroconidia to either mycelia or spherules, marked largely by changes in both protein-coding, tRNA, and unannotated loci. As little is known regarding the mechanisms governing these life stage transitions, these data provide better insight into those small RNA- and fragment-producing genes and loci that may be required for progression between Coccidioides saprobic and parasitic life cycles. Additionally, analysis of fragmentation patterns across all morphologies suggests unique patterns of RNA fragmentation across a cohort of RNA species that correlate with a given ecotype. Finally, we noted evidence of RNA export to the extracellular space, particularly regarding snRNA and tRNA-derived fragments as well as mRNA-derived transcripts, during the transition to either mycelia or spherules, which may play roles in cell-cell, and/or host-pathogen communication. Going forward, this newly established intra- and extracellular Coccidioides sRNA atlas will provide a foundation for potential biomarker discovery and contribute to our understanding of the molecular basis for virulence in Valley fever.
Project description:The aims of this study were to present modifications to the annotations of the genome of C. posadasii, one of two closely related species of Coccidioides, a dimorphic fungal pathogen that causes coccidioidomycosis, also called Valley Fever. Proteins present in lysates and filtrates of in vitro grown mycelia and parasitic phase spherules from C. posadasii strain Silveira were analyzed using a GeLC-MS/MS method.
Project description:Mouse strains have been identified that are resistant (i.e. DBA/2) or susceptible (i.e. C57BL/6) to infection from pathogenic fungus Coccidioides immitis. However, the genetic and immunological basis for this difference has not been fully characterized. Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis.
Project description:Mouse strains have been identified that are resistant (i.e. DBA/2) or susceptible (i.e. C57BL/6) to infection from pathogenic fungus Coccidioides immitis. However, the genetic and immunological basis for this difference has not been fully characterized. Microarray technology was used to identify genes that were differentially expressed in lung tissue between resistant DBA/2 and sensitive C57BL/6 mice after infection with C. immitis. C57BL/6 and DBA/2 mice were infected with arthoconidia of C. immitis and RNA was extracted at different days post-infection and hybridized to Affymetrix microarrays (MGU74Av2), in order to identify differentially expressed genes between the two strains.
Project description:Coccidioides immitis and posadasii are dimorphic fungi that transform from mycelia with internal arthroconidia in the soil to a tissue form known as a spherule. Genes that were highly up-regulated in young spherules include a spherule surface protein and iron and copper membrane transporters. Genes that are unique to Coccidioides spp. are also over-represented in this group, suggesting that they may be important for spherule differentiation. Enriched GO terms in up-regulated genes in young spherules include oxidation/reduction, response to stress and membrane proteins. Down-regulated genes are enriched for transcription factors, especially helix-loop-helix and C2H2 type zinc finger domain-containing proteins which is consistent with the dramatic change in transcriptional profile. Almost all genes that are up-regulated in young spherules remain up-regulated in mature spherules, but a small number of genes are differentially expressed in those two stages of spherule development. Mature spherules express more Hsp31, and amylase than young spherules and less tyrosinase. Some expression of transposons was detected and most of the differentially expressed transposons were up-regulated in spherules.
Project description:Coccidioides immitis (C. immitis) is a dimorphic fungus that causes disease in mammals including human beings. It grows as a mycelium in the soil but differentiates into a pathogenic structure called a spherule in the host. We compared the transcriptome of C. immitis mycelia and day 2 and day 8 spherules grown in vitro using a custom custom oligonucleotide microarray from Nimblegen.
