Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Functions of the Mediator subunit Med31 in Candida albicans support a role in shaping species-specific gene expression.

ABSTRACT: Mediator is an essential, evolutionarily conserved co-regulator of RNA polymerase II. Studies in model yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe showed remarkably conserved roles for Mediator despite high species divergence, and thus whether Mediator contributed to establishment of species-specific gene expression programs within related fungal species remains an open question. Here we show that in the fungal pathogen Candida albicans, the Mediator middle domain subunit Med31 has a conserved role with non-pathogenic model yeasts in regulation of Ace2-dependent cytokinesis genes and stress responses, but also additional roles in the transcription of genes associated with virulence traits: genes related to filamentous growth and gene families expanded in pathogenic vs non-pathogenic yeasts, such as the ALS adhesins and the FGR6 family of filamentous growth regulators. Consistently, Med31 is required for two key virulence attributes of C. albicans: filamentous growth and biofilm formation. Unlike our data in C. albicans, no role for Med31 in adhesin expression has been reported in model yeasts. To show biological relevance for the control over adhesin gene expression, we demonstrate that ALS1 is a relevant Med31 target for development of biofilms. Collectively, our data supports a role for Med31 in shaping species-specific gene expression in related fungal species. Two-color experimental design comparing cells with a ?med31 mutation with a control strain in which the MED31 gene was reintroduced. RNA from each replicate came from independent cultures.

ORGANISM(S): Candida albicans

SUBMITTER: Andre Nantel

PROVIDER: E-GEOD-31632 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Similar Datasets

Project description:The capacity to sense and transduce temperature signals pervades all aspects of biology, and temperature exerts powerful control over the development and virulence of diverse pathogens. In the leading fungal pathogen of humans, Candida albicans, temperature has a profound impact on morphogenesis, a key virulence trait. Many cues that induce the transition from yeast to filamentous growth are contingent on a minimum temperature of 37ÂºC, while further elevatation to 39ÂºC serves as an independent inducing cue. The molecular chaperone Hsp90 is a key regulator of C. albicans temperature-dependent morphogenesis, as induction of filamentous growth requires relief from Hsp90-mediated repression of the morphogenetic program. Compromise of Hsp90 function genetically, pharmacologically, or by elevated temperature induces filamentation in a manner that depends on protein kinase A (PKA) signaling, but is independent of the terminal transcription factor, Efg1. Here, we determine that despite morphological and regulatory differences, inhibition of Hsp90 induces a transcriptional profile similar to that induced by other filamentation cues, and does so in a manner that is independent of Efg1. Further, we identify Hms1 as a transcriptional regulator required for morphogenesis induced by elevated temperature or compromise of Hsp90 function. Hms1 functions downstream of the cyclin Pcl, and the cyclin-dependent kinase Pho85, both of which are required for temperature-dependent filamentation. Upon Hsp90 inhibition, Hms1 binds to DNA elements involved in filamentous growth, including UME6 and RBT5, and regulates their expression, providing a mechanism through which Pho85, Pcl1, and Hms1 govern morphogenesis. Consistent with the importance of morphogenetic flexibility with virulence, deletion of C. albicans HMS1 attenuates virulence in a metazoan model of infection. Thus, we establish a new mechanism through which Hsp90 orchestrates C. albicans morphogenesis, and define novel regulatory circuitry governing a temperature-dependent developmental program, with broad implications for temperature sensing and virulence of microbial pathogens. Genome-wide occupancy experiments (Chip-CHIP) of FLAG-tagged Hms1p from cells grown in the presence or absence of geldanamycin (GldA). Co-precipitating genomic DNA was labelled and hybridized to whole-genome tiling arrays.

Project description:The capacity to sense and transduce temperature signals pervades all aspects of biology, and temperature exerts powerful control over the development and virulence of diverse pathogens. In the leading fungal pathogen of humans, Candida albicans, temperature has a profound impact on morphogenesis, a key virulence trait. Many cues that induce the transition from yeast to filamentous growth are contingent on a minimum temperature of 37ÂºC, while further elevatation to 39ÂºC serves as an independent inducing cue. The molecular chaperone Hsp90 is a key regulator of C. albicans temperature-dependent morphogenesis, as induction of filamentous growth requires relief from Hsp90-mediated repression of the morphogenetic program. Compromise of Hsp90 function genetically, pharmacologically, or by elevated temperature induces filamentation in a manner that depends on protein kinase A (PKA) signaling, but is independent of the terminal transcription factor, Efg1. Here, we determine that despite morphological and regulatory differences, inhibition of Hsp90 induces a transcriptional profile similar to that induced by other filamentation cues, and does so in a manner that is independent of Efg1. Further, we identify Hms1 as a transcriptional regulator required for morphogenesis induced by elevated temperature or compromise of Hsp90 function. Hms1 functions downstream of the cyclin Pcl, and the cyclin-dependent kinase Pho85, both of which are required for temperature-dependent filamentation. Upon Hsp90 inhibition, Hms1 binds to DNA elements involved in filamentous growth, including UME6 and RBT5, and regulates their expression, providing a mechanism through which Pho85, Pcl1, and Hms1 govern morphogenesis. Consistent with the importance of morphogenetic flexibility with virulence, deletion of C. albicans HMS1 attenuates virulence in a metazoan model of infection. Thus, we establish a new mechanism through which Hsp90 orchestrates C. albicans morphogenesis, and define novel regulatory circuitry governing a temperature-dependent developmental program, with broad implications for temperature sensing and virulence of microbial pathogens. Two-color experimental design testing the effect of geldanamycin on wild type of delta-efg1 cells. RNA from each replicate came from independent cultures.

Project description:Compared to other model organisms and despite the clinical relevance of the pathogenic yeast Candida albicans, no comprehensive analysis has been done to provide experimental support of its in silico-based genome annotation. Here we have undertaken a genome-wide experimental annotation to accurately uncover the transcriptional landscape of the pathogenic yeast C. albicans using strand-specific high-density tiling arrays. RNAs were purified from cells growing under conditions relevant to C. albicans pathogenicity, including biofilm, lab-grown yeast and serum-induced hyphae as well as cells isolated from the mouse caecum. This work provides a genome-wide experimental validation for a large number of predicted ORFs for which transcription had not been detected by other approaches. Additionally, we identified more than 2000 novel transcriptional segments, including new ORFs and exons, non-coding RNAs (ncRNA) as well as convincing cases of antisense gene transcription. We also characterized the 5’- and 3’-untranslated regions (UTR) of expressed ORFs, and established that genes with long 5’UTRs are significantly enriched in regulatory functions controlling filamentous growth. Furthermore, we found that genomic regions adjacent to telomeres harbor a cluster of expressed ncRNAs. To validate and confirm new ncRNA candidates, we adapted an iterative strategy combining both genome-wide occupancy of the different subunits of RNA polymerases I, II and III, and expression data. This comprehensive approach allowed the identification of different families of ncRNA. In summary, we provide a comprehensive expression atlas that covers relevant C. albicans pathogenic developmental stages in addition to a discovery of new ORF and non-coding genetic elements. We have undertaken a genome-wide experimental annotation to accurately uncover the transcriptional landscape of the pathogenic yeast C. albicans using strand-specific high-density tiling arrays. RNAs were purified from cells growing under conditions relevant to Candida albicans pathogenicity, including biofilm, lab-grown yeast and serum-induced hyphae as well as cells isolated from the mouse caecum. We also adapted a strategy in which genome-wide occupancy of different subunits of RNA polymerases (RNAP) I, II and III, is combined with expression data to annotate ncRNAs resulting from real transcriptional events. For this purpose we have performed ChIP-chip of subunits that represent the three RNAP machines in C. albicans cells growing in rich media (YPD) at 30°C. In this study, we performed peak detection only for RNA Polymerase III (Rpc82p). All detected peaks and their genomic features are included as a supplementary file on the Sample record (GSM561024).

Dataset Information

Functions of the Mediator subunit Med31 in Candida albicans support a role in shaping species-specific gene expression.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets