A conserved transcriptional regulator governs fungal morphology in widely diverged species
Ontology highlight
ABSTRACT: This SuperSeries is composed of the following subset Series: GSE32550: A conserved transcriptional regulator governs fungal morphology in widely diverged species [expression data] GSE32557: A conserved transcriptional regulator governs fungal morphology in widely diverged species [ChIP-chip, Transcriptional regulation by Mit1 and orthologs] Refer to individual Series
Project description:In this paper, we examine orthologs of a transcriptional regulator in three fungal species, Saccharomyces cerevisiae, Candida albicans, and Histoplasma capsulatum. We show that, despite an estimated 600 million years since those species diverged from a common ancestor, Wor1 in C. albicans, Ryp1 in H. capsulatum, and Mit1 in S. cerevisiae recognize the same DNA motif. Previous work established that Wor1 regulates white-opaque switching in C. albicans and that its ortholog Ryp1 regulates the yeast to mycelial transition in H. capsulatum. Here we show that the ortholog Mit1 in S. cerevisiae also regulates a morphological transition, in this case pseudohyphal growth. Full genome chromatin immunoprecipitation experiments show that Mit1 binds to the control regions of approximately 94 genes including the previously known regulators of pseudohyphal growth. Through a comparison of full genome chromatin immunoprecipitation experiments for Mit1 in S. cerevisiae, Wor1 in C. albicans, and Wor1 ectopically expressed in S. cerevisiae, we conclude that genes controlled by the orthologous regulators overlap only slightly between these two species. We suggest that the ancestral Wor1/Mit1/Ryp1 protein controlled aspects of cell morphology and that evolutionary movement of genes in and out of the Wor1/Mit1/Ryp1 regulon is responsible, in part, for the differences of morphological forms among these species. Consistent with this idea, ectopic expression of C. albicans Wor1 or H. capsulatum Ryp1 can drive the pseudohyphal growth program in S. cerevisiae. IP strains were compared to untagged or deletion control strains
Project description:In this paper, we examine orthologs of a transcriptional regulator in three fungal species, Saccharomyces cerevisiae, Candida albicans, and Histoplasma capsulatum. We show that, despite an estimated 600 million years since those species diverged from a common ancestor, Wor1 in C. albicans, Ryp1 in H. capsulatum, and Mit1 in S. cerevisiae recognize the same DNA motif. Previous work established that Wor1 regulates white-opaque switching in C. albicans and that its ortholog Ryp1 regulates the yeast to mycelial transition in H. capsulatum. Here we show that the ortholog Mit1 in S. cerevisiae also regulates a morphological transition, in this case pseudohyphal growth. Full genome chromatin immunoprecipitation experiments show that Mit1 binds to the control regions of approximately 94 genes including the previously known regulators of pseudohyphal growth. Through a comparison of full genome chromatin immunoprecipitation experiments for Mit1 in S. cerevisiae, Wor1 in C. albicans, and Wor1 ectopically expressed in S. cerevisiae, we conclude that genes controlled by the orthologous regulators overlap only slightly between these two species. We suggest that the ancestral Wor1/Mit1/Ryp1 protein controlled aspects of cell morphology and that evolutionary movement of genes in and out of the Wor1/Mit1/Ryp1 regulon is responsible, in part, for the differences of morphological forms among these species. Consistent with this idea, ectopic expression of C. albicans Wor1 or H. capsulatum Ryp1 can drive the pseudohyphal growth program in S. cerevisiae. Replicate experiments for each of four strains compared with reference sample - WT, a Mit1 deletion haploid A strain, a Yhr177w deletion haploid A strain, and a double deletion haploid A strain. All were in the sigma 2000 background.
Project description:The mammalian gastrointestinal tract and the bloodstream are highly disparate biological niches, and yet certain commensal-pathogenic microorganisms are able to thrive in both environments. Here, we report the evolution of a unique transcription circuit in the yeast, Candida albicans, which determines its fitness in both host niches. Our comprehensive analysis of the DNA-binding proteins that regulate iron uptake by this organism suggests the evolutionary intercalation of a transcriptional activator called Sef1 between two broadly conserved transcriptional repressors, Sfu1 and Hap43. The Sef1 activator of iron uptake genes promotes virulence in a mouse model of bloodstream infection, whereas the Sfu1 repressor is dispensable for virulence but promotes gastrointestinal commensalism. We propose that the ability to alternate between genetic programs conferring resistance to iron depletion in the bloodstream versus iron toxicity in the gut may be a fundamental attribute of gastrointestinal commensal-pathogens. ChIP analyses to profile genome-wide of distribution of Sef1, Sfu1 and Hap43 in response to various iron availability. 12 independent ChIP experiments were performed on 6 biological replicates of the untagged control and 2 biological replicates each of Sef1-Myc, Sfu1-Myc, and Hap43-Myc.
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:The dataset contains ChIP-Seq data of the Set3 and Hos2 proteins in Candida albicans, assayed in two morphological phases (yeast and hypha). The Set3 and Hos2 proteins in the respective strains carry 9myc epitopes and ChIP was performed with an anti-myc antibody. Included samples are the following: 1 input and 1 ChIP sample of an untagged wild type strain as negative control assayed in the yeast phase, 1 input and 3 ChIP biological replicates of the Set3-9myc strain in the yeast phase, 1 input and 2 ChIP biological replicates of the Set3-9myc strain in the hypha phase, 1 input and 2 ChIP biological replicates of the Hos2-9myc strain in the yeast phase, 1 input and 2 ChIP biological replicates of the Hos2-9myc strain in the hypha phase, 1 input and 3 ChIP biological replicates of Set3-9myc in a set1delta/delta background in the yeast phase. ChIP-Seq was performed of Candida albicans strains in two morphological phases (yeast and hypha). Yeast-phase cells were grown to the exponential phase in YPD at 30C. Hyphal differentiation was induced by resuspending the cells in YPD+20% Fetal Calf Serum and a shift of the growth temperature to 37C. Induction was performed for 30 minutes. Cells were crosslinked with 1% formaldehyde for 15 minutes at room temperature.
Project description:The ability to grow at host temperature is a critical trait for most pathogenic microbes of humans. Thermally dimorphic fungal pathogens, including Histoplasma capsulatum, are a class of soil fungi that undergo a dramatic change in cell shape and virulence gene expression in response to host temperature. Here we elucidate a complex temperature-responsive network in H. capsulatum, which switches from an environmental filamentous form to a pathogenic yeast form. We dissect the circuit driven by three regulators that control yeast-phase growth, and demonstrate that these factors, including two deeply conserved Velvet family proteins of unknown function, associate with DNA. We identify and characterize a fourth regulator of this pathway, and define cis-acting motifs that recruit these transcription factors to a tightly interwoven network of temperature-responsive target genes. Our results provide the first comprehensive analysis of the complex transcriptional network that links temperature to morphology and virulence in thermally dimorphic fungi. This submission gives the chromatin immunoprecipitation results. For each of the four Ryp proteins, ChIP vs. input hybridizations were performed for three replicate immunoprecipitations from the wild-type strain and two negative control replicates from the corresponding mutant strain.
Project description:Here we present the study on ChIP-chip mapping of the genomic binding sites for Sty1, Atf1, and the Atf1's binding partner Pcr1; the genome-wide transcriptional profiling of the atf1 and pcr1 strains in response to H2O2; and the phenotypic assessment of ~90 Atf1/Pcr1-bound or unbound genes for growth fitness under H2O2 conditions. ChIP-chip analysis shows that Atf1 and Pcr1 binding sites are overlapped in the genome and constitutively present before H2O2 stress. On the other hand, Sty1 recruitment primarily occurs at the Atf1/Pcr1 binding sites and is induced by H2O2. We found that Atf1/Pcr1 is clearly responsible for the high-level transcriptional response to H2O2. Furthermore, phenotypic assessment indicates that among the H2O2-induced genes, Atf1/Pcr1-bound genes exhibit a higher likelihood of functional requirement for growth fitness under the stress condition than the Atf1/Pcr1-unbound genes do. Notably, we found that the Atf1/Pcr1-bound genes regardless of their responsiveness to H2O2 show a high probability of requirement for growth fitness. . Expression level of genes in triplicates at 0min (without stress) is compared with that at 10, 30, 60, and 120min after stress treatment. ChIP-chip analyses is done for Atf1-HA, pcr1-HA, sty1-HA, Sty1-HA allele in the atf1D or pcr1D background without and with H2O2 (0.5mM for 30min).
Project description:Investigation of whole genome gene expression level changes in Spathaspora passalidarum NRRL Y-27907 grown aerobically in xylose, compared to the same strain grown aerobically in glucose. A six array study using total RNA recovered from three separate cultures of Spathaspora passalidarum NRRL Y-27907 grown in glucose and three separate cultures of Spathaspora passalidarum NRRL Y-27907 grown in xylose. Each array measures the expression level of 362,487 probes (average probe length 54.5 +/- 4.0 nt) tiled across the Spathaspora passalidarum NRRL Y-27907 genome with a median spacing distance of 29 nt. During data processing, probes are filtered to include only those probes corresponding to annotated protein-coding genes.