Project description:Candida albicans is associated with humans as both a harmless commensal organism and a pathogen. Cph2 is a transcription factor whose DNA binding domain is similar to mammalian sterol response element binding proteins (SREBPs). SREBPs are master regulators of cellular cholesterol levels, and are highly conserved from fungi to mammals. However, ergosterol biosynthesis is regulated by the zinc finger transcription factor Upc2 in C. albicans and several other yeasts. Cph2 is not necessary for ergosterol biosynthesis, but important for colonization in the murine gastrointestinal tract. Here we demonstrate that Cph2 is a membrane-associated transcription factor that is processed to release the N-terminal DNA binding domain like SREBPs; but its cleavage is not regulated by cellular levels of ergosterol or oxygen. ChIP-Seq shows that Cph2 binds to the promoters of HMS1 and other components of the regulatory circuit for GI tract colonization. In addition, 50% of Cph2 targets are also bound by Hms1 and other factors of the regulatory circuit. Several common targets function at the head of the glycolysis pathway. Thus, Cph2 is an integral part of the regulatory circuit for GI colonization that regulates glycolytic flux. RNA-seq shows a significant overlap in genes differentially regulated by Cph2 and hypoxia, and Cph2 is important for optimal expression of some hypoxia-responsive genes in glycolysis and the citric acid cycle. We suggest that Cph2 and Upc2 regulate hypoxia-responsive expression in different pathways, consistent with a synthetic lethal defect of the cph2 upc2 double mutant in hypoxia. Genome binding/occupancy profiling by high throughput sequencing. ChIP-seq of Cph2 was carried out in a wild-type strain carrying N-terminal myc-tagged Cph2 under the MAL2 promoter (MAL2-myc-Cph2N). IP and INPUT samples from 2 independent experiments, as well as a sample of untagged wild-type control, were sequenced.
Project description:The differentiation of cells into distinct cell types, each of which is heritable for many generations, underlies many biological phenomena. White and opaque cells of the fungal pathogen Candida albicans are two such heritable cell types, each thought to be adapted to unique niches within their human host. To systematically investigate the differences between the two cell types, we performed strand-specific massively-parallel sequencing of RNA from C. albicans white and opaque cells. Combining the resulting data from both cell types, we first substantially re-annotated the C. albicans transcriptome, finding 1443 novel coding and non-coding transcriptionally active regions. Using the new annotation, we compared differences in transcript abundance between the two cell types with the genomic regions bound by the master regulator of the white-opaque switch (Wor1). We found that the revised transcriptional landscape considerably alters our understanding of the circuit governing differentiation. In particular, we can now resolve the poor concordance between binding of the master regulator and the differential expression of adjacent genes, a discrepancy observed in many other studies of cell differentiation. More than one third of the Wor1-bound differentially-expressed transcripts were previously unannotated, which explains the formerly puzzling presence of Wor1 at these positions along the genome. Indeed, many of these newly identified Wor1-regulated genes are non-coding and transcribed antisense to coding transcripts. We also found that 5' and 3' untranslated regions (UTRs) of mRNAs in the circuit are unusually long and that 5' UTRs often differ in length between white and opaque cells. These observations suggest that the use of alternative promoters is widespread in the circuit and that important regulatory information is carried in the long UTRs. Further analysis revealed that the revised Wor1 circuit bears several striking similarities to the Oct4 circuit that specifies the pluripotency of mammalian embryonic stem cells. Additional characteristics shared with the Oct4 circuit suggest a set of general hallmarks characteristic of heritable differentiation states in eukaryotes. RNA-Seq was applied to Candida albicans white and opaque cells to identify novel transcripts and UTRs that are differentially regulated between the two cell types. Two biological replicates each of white and opaque cell cultures. One of the white cell RNA samples was split just after isolation to allow a comparison of the poly(A)-selection and ribo-depletion sample preparation strategies.
Project description:This data was generated to compare genome-wide expression differences between a major fungal pathogen of humans, Candida albicans and its less pathogenic relative, Candida dubliniensis, using interspecies hybrids to systematically identify cis-regulatory adaptations.
Project description:The human fungal pathogen Candida albicans can switch between two cell types, âwhiteâ and âopaque,â each of which is heritable through many cell divisions. Switching between these two cell types is regulated by six transcriptional regulators which form a highly interconnected circuit with multiple feedback loops. Here, we identify a seventh regulator of white-opaque switching, which we have named Wor4. We show that ectopic expression of Wor4 is sufficient to drive switching from the white to the opaque cell type and that deletion of Wor4 blocks switching from the white to the opaque cell type. A combination of ectopic expression and deletion experiments indicates that Wor4 is positioned upstream of Wor1 and that it is formally an activator of the opaque cell type. The combination of ectopic expression and deletion phenotypes for Wor4 is unique; none of the other six white-opaque regulators show this pattern. We determined the pattern of Wor4 binding across the genome by ChIP-seq and found it is highly correlated with that of Wor1 and Wor2, indicating that Wor4 is tightly integrated into the existing white-opaque regulatory circuit. We previously proposed that white-to-opaque switching relies on the activation of a complex circuit of feedback loops that remains excited through many cell divisions. The identification of a new, central regulator of white-opaque switching supports this idea by indicating that the white-opaque switching mechanism is considerably more complex than those controlling conventional, non-heritable patterns of gene expression. C. albicans Wor4-GFP versus untagged control in both white and opaque cell types. Cells grown in SD+aa+Uri at 25°C with three technical replicates of each strain/cell type (12 total).
Project description:Candida albicans is associated with humans as both a harmless commensal organism and a pathogen. Cph2 is a transcription factor whose DNA binding domain is similar to mammalian sterol response element binding proteins (SREBPs). SREBPs are master regulators of cellular cholesterol levels, and are highly conserved from fungi to mammals. However, ergosterol biosynthesis is regulated by the zinc finger transcription factor Upc2 in C. albicans and several other yeasts. Cph2 is not necessary for ergosterol biosynthesis, but important for colonization in the murine gastrointestinal tract. Here we demonstrate that Cph2 is a membrane-associated transcription factor that is processed to release the N-terminal DNA binding domain like SREBPs; but its cleavage is not regulated by cellular levels of ergosterol or oxygen. ChIP-Seq shows that Cph2 binds to the promoters of HMS1 and other components of the regulatory circuit for GI tract colonization. In addition, 50% of Cph2 targets are also bound by Hms1 and other factors of the regulatory circuit. Several common targets function at the head of the glycolysis pathway. Thus, Cph2 is an integral part of the regulatory circuit for GI colonization that regulates glycolytic flux. RNA-seq shows a significant overlap in genes differentially regulated by Cph2 and hypoxia, and Cph2 is important for optimal expression of some hypoxia-responsive genes in glycolysis and the citric acid cycle. We suggest that Cph2 and Upc2 regulate hypoxia-responsive expression in different pathways, consistent with a synthetic lethal defect of the cph2 upc2 double mutant in hypoxia.
Project description:Candida albicans is associated with humans as both a harmless commensal organism and a pathogen. Cph2 is a transcription factor whose DNA binding domain is similar to mammalian sterol response element binding proteins (SREBPs). SREBPs are master regulators of cellular cholesterol levels, and are highly conserved from fungi to mammals. However, ergosterol biosynthesis is regulated by the zinc finger transcription factor Upc2 in C. albicans and several other yeasts. Cph2 is not necessary for ergosterol biosynthesis, but important for colonization in the murine gastrointestinal tract. Here we demonstrate that Cph2 is a membrane-associated transcription factor that is processed to release the N-terminal DNA binding domain like SREBPs; but its cleavage is not regulated by cellular levels of ergosterol or oxygen. ChIP-Seq shows that Cph2 binds to the promoters of HMS1 and other components of the regulatory circuit for GI tract colonization. In addition, 50% of Cph2 targets are also bound by Hms1 and other factors of the regulatory circuit. Several common targets function at the head of the glycolysis pathway. Thus, Cph2 is an integral part of the regulatory circuit for GI colonization that regulates glycolytic flux. RNA-seq shows a significant overlap in genes differentially regulated by Cph2 and hypoxia, and Cph2 is important for optimal expression of some hypoxia-responsive genes in glycolysis and the citric acid cycle. We suggest that Cph2 and Upc2 regulate hypoxia-responsive expression in different pathways, consistent with a synthetic lethal defect of the cph2 upc2 double mutant in hypoxia. Expression profiling by high throughput sequencing. RNA sequencing was performed on wild type and cph2 deletion strains. 2 biological replicates were sequenced for each strain.
Project description:To investigate the effect of Progranulin on neutrophils phagocytosis and killing of Candida albicans, we designed RNA-Seq analysis of wild-type and PGRN-/- neutrophils challenged with Candida albicans in vitro at one time point.
Project description:To investigate the effect of progranulin on macrophages phagocytosis and killing of Candida albicans, we designed RNA-Seq analysis of wild-type and PGRN-/- macrophages challenged with Candida albicans in vitro at one time point.