A Multistate Toggle Switch Defines Fungal Cell Fates and Is Regulated by Synergistic Genetic Cues

Anderson, Matthew; Porman, Allison M.; Wang, Na; Mancera, Eugenio; Huang, Denis; Cuomo, Christina A.; Bennett, Richard J.

doi:10.1371/journal.pgen.1006353

Cited by 24 publications

(31 citation statements)

References 89 publications

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“…The white-opaque switch is currently thought to have evolved in the ancestor to C. albicans and Candida tropicalis and regulates sexual competency in both extant species (48,49). Given our identification of MAPK signaling differences between C. albicans white and opaque cells, we examined C. tropicalis transcriptome data (50) and found that STE4 was expressed at a twofold higher level in opaque cells than in white cells (SI Appendix, Fig. S7).…”

Section: Discussionmentioning

confidence: 99%

Epigenetic control of pheromone MAPK signaling determines sexual fecundity in Candida albicans

Scaduto

Kabrawala

Thomson

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Several pathogenic species are capable of heritable and reversible switching between two epigenetic states, "white" and "opaque." In, white cells are essentially sterile, whereas opaque cells are mating-proficient. Here, we interrogate the mechanism by which the white-opaque switch regulates sexual fecundity and identify four genes in the pheromone MAPK pathway that are expressed at significantly higher levels in opaque cells than in white cells. These genes encode the β subunit of the G-protein complex (), the pheromone MAPK scaffold (), and the two terminal MAP kinases (). To define the contribution of each factor to mating, white cells were reverse-engineered to express elevated, opaque-like levels of these factors, either singly or in combination. We show that white cells co-overexpressing, , and undergo mating four orders of magnitude more efficiently than control white cells and at a frequency approaching that of opaque cells. Moreover, engineered white cells recapitulate the transcriptional and morphological responses of opaque cells to pheromone. These results therefore reveal multiple bottlenecks in pheromone MAPK signaling in white cells and that alleviation of these bottlenecks enables efficient mating by these "sterile" cell types. Taken together, our findings establish that differential expression of several MAPK factors underlies the epigenetic control of mating in We also discuss how fitness advantages could have driven the evolution of a toggle switch to regulate sexual reproduction in pathogenic species.

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Section: Discussionmentioning

confidence: 99%

Epigenetic control of pheromone MAPK signaling determines sexual fecundity in Candida albicans

Scaduto

Kabrawala

Thomson

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Taken together, our data show that in wild-type cells, inhibition of the Ryp pathway by an Msb2-dependent mechanism is likely to be a key step in the switch from yeast to filaments in response to temperature. Notably, in Candida spp , an antagonistic regulatory relationship between Wor1 (an ortholog of the H. capsulatum Ryp1 protein) and Efg1 (an ortholog of the H. capsulatum Stu1 protein) is critical for controlling the switch between distinct developmental states [36, 51–53].…”

Section: Discussionmentioning

confidence: 99%

Opposing signaling pathways regulate morphology in response to temperature in the fungal pathogenHistoplasma capsulatum

Rodriguez

Voorhies

Gilmore

et al. 2019

Preprint

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19 20 21 22 23 2 24 25 ABSTRACT26 Phenotypic switching between two opposing cellular states is a fundamental aspect of biology, 27 and fungi provide facile systems to analyze the interactions between regulons that control this 28 type of switch. A long-standing mystery in fungal pathogens of humans is how thermally 29 dimorphic fungi switch their developmental form in response to temperature. These fungi, 30 including the subject of this study, Histoplasma capsulatum, are temperature-responsive 31 organisms that utilize unknown regulatory pathways to couple their cell shape and associated 32 attributes to the temperature of their environment. H. capsulatum grows as a multicellular hypha 33 in the soil that switches to a pathogenic yeast form in response to the temperature of a 34 mammalian host. These states can be triggered in the laboratory simply by growing the fungus 35 either at room temperature (where it grows as hyphae) or at 37ºC (where it grows as yeast). Prior 36 worked revealed that 15-20% of transcripts are differentially expressed in response to 37 temperature, but it is unclear which transcripts are linked to specific phenotypic changes such as 38 cell morphology or virulence. To elucidate temperature-responsive regulons, we previously 39 identified four transcription factors (Ryp1-4) that are required for yeast-phase growth at 37ºC; in 40 each ryp mutant, the fungus grows constitutively as hyphae regardless of temperature and the 41 cells fail to express genes that are normally induced in response to growth at 37ºC. Here we 42 perform the first genetic screen to identify genes required for hyphal growth of H. capsulatum at 43 room temperature and find that disruption of the signaling mucin MSB2 results in a yeast-locked 44 phenotype. RNAseq experiments reveal that MSB2 is not required for the majority of gene 45 expression changes that occur when cells are shifted to room temperature. However, a small 46 subset of temperature-responsive genes is dependent on MSB2 for its expression, thereby 3 47 implicating these genes in the process of filamentation. Disruption or knockdown of an Msb2-48 dependent MAP kinase (HOG2) and an APSES transcription factor (STU1) prevents hyphal 49 growth at room temperature, validating that the Msb2 regulon contains genes that control 50 filamentation. Notably, the Msb2 regulon shows conserved hyphal-specific expression in other 51 dimorphic fungi, suggesting that this work defines a small set of genes that are likely to be 52 conserved regulators and effectors of filamentation in multiple fungi. In contrast, a few yeast-53 specific transcripts, including virulence factors that are normally expressed only at 37ºC, are 54 inappropriately expressed at room temperature in the msb2 mutant, suggesting that expression of 55 these genes is coupled to growth in the yeast form rather than to temperature. Finally, we find 56 that the yeast-promoting transcription factor Ryp3 associates with the MSB2 promoter and 57 inhibits MSB2 transcript expression at 37ºC, whereas Msb2 inhibits...

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“…The previously reported white and opaque Tef2-GFP and Tef2-mCherry strains (Takagi et al 2019) are derived from the switching capable AHY135 strain (Hernday et al 2013), where the HIS1 and LEU2 markers were added back to RZY47, itself a sorbose selected a / a copy of the SN87 a /α his1 leu2 strain (Noble and Johnson 2005; Zordan et al 2006). C. albicans clinical isolates L26 and P37005 (Lockhart et al 2002), C. dubliniensis CD36 (Sullivan et al 1995), C. tropicalis MYA3404 (Joly et al 1996), the C. tropicalis AM2005/0093 derived white-opaque switching strains (Anderson et al 2016), and Candida parapsilosis CBS604/ATCC22019 (Guerin et al 1989) have all been previously reported.…”

Section: Methodsmentioning

confidence: 96%

An opaque cell-specific expression program of secreted proteases and transporters allows cell-type cooperation inCandida albicans

Lohse

Brenes

Ziv

et al. 2020

Preprint

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An unusual feature of the opportunistic pathogen C. albicans is its ability to stochastically switch between two distinct, heritable cell types called white and opaque. Here, we show that only opaque cells, in response to environmental signals, massively up-regulate a specific group of secreted proteases and peptide transporters, allowing exceptionally efficient use of proteins as sources of nitrogen. We identify the specific proteases (members of the secreted aspartyl protease (SAP) family) needed for opaque cells to proliferate under these conditions, and we identify four transcriptional regulators of this specialized proteolysis and uptake program. We also show that, in mixed cultures, opaque cells enable white cells to also proliferate efficiently when proteins are the sole nitrogen source. Based on these observations, we suggest that one role of white-opaque switching is to create mixed populations where the different phenotypes derived from a single genome are shared between two distinct cell types.SummaryThe opportunistic human fungal pathogen Candida albicans switches between two distinct, heritable cell types, named “white” and “opaque.” We show that opaque cells, in response to proteins as the sole nitrogen source, up-regulate a specialized program, including specific secreted aspartyl proteases and peptide transporters. We demonstrate that, in mixed cultures, opaque cells enable white cells to respond and proliferate more efficiently under these conditions. These observations suggest that white-opaque switching creates mixtures of cells where the population characteristics - which derive from a single genome - reflect the contributions of two distinct cell types.Dataset Reference NumbersThe .RAW files for both sets of Mass Spectrometry experiments have been deposited at the ProteoSAFe resource (https://proteomics.ucsd.edu/ProteoSAFe/).MSP-MS experiment reference number: MSV000085279. For reviewer access use login “MSV000085279_reviewer” and password “candidamspms”.Proteomics experiment reference number: MSV000085283. For reviewer access use login “MSV000085283_reviewer” and password “candidaprot”.

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A Multistate Toggle Switch Defines Fungal Cell Fates and Is Regulated by Synergistic Genetic Cues

Cited by 24 publications

References 89 publications

Epigenetic control of pheromone MAPK signaling determines sexual fecundity in Candida albicans

Epigenetic control of pheromone MAPK signaling determines sexual fecundity in Candida albicans

Opposing signaling pathways regulate morphology in response to temperature in the fungal pathogenHistoplasma capsulatum

An opaque cell-specific expression program of secreted proteases and transporters allows cell-type cooperation inCandida albicans

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