Gene dosage and protein valency impact phase separation and fungal cell fate.

Cell fate decisions in eukaryotes are regulated by interconnected networks of transcription factors (TFs) that drive heritable changes in identity. However, much is unknown about how TFs act together to control cell fate, despite links to cellular dysfunction and disease when TF function is aberrant. Here, we addressed the interplay between TFs that control heritable switching in the diploid fungal pathogen Candida albicans.

Transcriptional control of white-opaque switching and modulation by environmental cues and strain background.

The opportunistic fungal pathogen can undergo cellular transitions in response to environmental cues that impact its lifestyle and its interactions with the human host. This is exemplified by the white-opaque switch, which is a heritable transition between two phenotypic states that is regulated by a highly interconnected network of transcription factors (TFs). To obtain greater understanding of the transcriptional regulation of the switch, we generated a genome-wide, tetracycline-inducible TF library in the WO-1 strain background and identified those TFs whose forced expression induces white cells to switch to the opaque state.

Aneuploidy confers a unique transcriptional and phenotypic profile to Candida albicans.

Inaccurate chromosome segregation can lead to the formation of aneuploid cells that harbor an imbalanced complement of chromosomes. Several fungal species are not only able to tolerate the detrimental effects of aneuploidy but can use it to adapt to environmental pressures. The fungal pathobiont Candida albicans frequently acquires supernumerary chromosomes that enable growth in the presence of antifungal drugs or in specific host niches, yet the transcriptional changes associated with aneuploidy are not globally defined.

The hyphal-specific toxin candidalysin promotes fungal gut commensalism.

The fungus Candida albicans frequently colonizes the human gastrointestinal tract, from which it can disseminate to cause systemic disease. This polymorphic species can transition between growing as single-celled yeast and as multicellular hyphae to adapt to its environment. The current dogma of C.

Filamentation and biofilm formation are regulated by the phase-separation capacity of network transcription factors in Candida albicans.

The ability of the fungus Candida albicans to filament and form biofilms contributes to its burden as a leading cause of hospital-acquired infections. Biofilm development involves an interconnected transcriptional regulatory network (TRN) consisting of nine transcription factors (TFs) that bind both to their own regulatory regions and to those of the other network TFs. Here, we show that seven of the nine TFs in the C.

The reference strain SC5314 contains a rare, dominant allele of the transcription factor Rob1 that modulates filamentation, biofilm formation, and oral commensalism.

is a commensal fungus that colonizes the human oral cavity and gastrointestinal tract but also causes mucosal as well as invasive disease. The expression of virulence traits in clinical isolates is heterogeneous and the genetic basis of this heterogeneity is of high interest. The reference strain SC5314 is highly invasive and expresses robust filamentation and biofilm formation relative to many other clinical isolates.

The reference strain SC5314 contains a rare, dominant allele of the transcription factor Rob1 that modulates biofilm formation and oral commensalism.

Unlabelled: is a diploid human fungal pathogen that displays significant genomic and phenotypic heterogeneity over a range of virulence traits and in the context of a variety of environmental niches. Here, we show that the effects of Rob1 on biofilm and filamentation virulence traits is dependent on both the specific environmental condition and the clinical strain of . The reference strain SC5314 is a heterozygote with two alleles that differ by a single nucleotide polymorphism at position 946 resulting in a serine or proline containing isoform.

Rewilding of laboratory mice enhances granulopoiesis and immunity through intestinal fungal colonization.

The paucity of blood granulocyte populations such as neutrophils in laboratory mice is a notable difference between this model organism and humans, but the cause of this species-specific difference is unclear. We previously demonstrated that laboratory mice released into a seminatural environment, referred to as rewilding, display an increase in blood granulocytes that is associated with expansion of fungi in the gut microbiota. Here, we find that tonic signals from fungal colonization induce sustained granulopoiesis through a mechanism distinct from emergency granulopoiesis, leading to a prolonged expansion of circulating neutrophils that promotes immunity.

Glucose depletion enables Candida albicans mating independently of the epigenetic white-opaque switch.

The human fungal pathogen Candida albicans can switch stochastically and heritably between a "white" phase and an "opaque" phase. Opaque cells are the mating-competent form of the species, whereas white cells are thought to be essentially "sterile". Here, we report that glucose depletion, a common nutrient stress, enables C.

Aneuploidy and gene dosage regulate filamentation and host colonization by .

Aneuploidy is a frequent occurrence in fungal species where it can alter gene expression and promote adaptation to a variety of environmental cues. Multiple forms of aneuploidy have been observed in the opportunistic fungal pathogen which is a common component of the human gut mycobiome but can escape this niche and cause life-threatening systemic disease. Using a barcode sequencing (Bar-seq) approach, we evaluated a set of diploid strains and found that a strain carrying a third copy of chromosome (Chr) 7 was associated with increased fitness during both gastrointestinal (GI) colonization and systemic infection.

Phase separation in fungi.

Phase separation, in which macromolecules partition into a concentrated phase that is immiscible with a dilute phase, is involved with fundamental cellular processes across the tree of life. We review the principles of phase separation and highlight how it impacts diverse processes in the fungal kingdom. These include the regulation of autophagy, cell signalling pathways, transcriptional circuits and the establishment of asymmetry in fungal cells.

An Adjuvant-Based Approach Enables the Use of Dominant and Selectable Markers in Candida albicans.

Candida albicans is a pathobiont fungus that can colonize multiple niches in the human body but is also a frequent cause of both mucosal and systemic disease. Despite its clinical importance, a paucity of dominant selectable markers has hindered the development of tools for genetic manipulation of the species. One factor limiting the utilization of dominant selectable markers is that C.

Friendly fungi: symbiosis with commensal Candida albicans.

Mucosal tissues are constitutively colonized by a wide assortment of host-adapted microbes. This includes the polymorphic fungus Candida albicans which is a primary target of human adaptive responses. Immunogenicity is replicated after intestinal colonization in preclinical models with a surprising array of protective benefits for most hosts, but harmful consequences for a few.

Candida albicans oscillating UME6 expression during intestinal colonization primes systemic Th17 protective immunity.

Systemic immunity is stringently regulated by commensal intestinal microbes, including the pathobiont Candida albicans. This fungus utilizes various transcriptional and morphological programs for host adaptation, but how this heterogeneity affects immunogenicity remains uncertain. We show that UME6, a transcriptional regulator of filamentation, is essential for intestinal C.

Candida albicans Isolates 529L and CHN1 Exhibit Stable Colonization of the Murine Gastrointestinal Tract.

Candida albicans is a pathobiont that colonizes multiple niches in the body including the gastrointestinal (GI) tract but is also responsible for both mucosal and systemic infections. Despite its prevalence as a human commensal, the murine GI tract is generally refractory to colonization with the C. albicans reference isolate SC5314.

Intraspecies Transcriptional Profiling Reveals Key Regulators of Candida albicans Pathogenic Traits.

The human commensal and opportunistic fungal pathogen displays extensive genetic and phenotypic variation across clinical isolates. Here, we performed RNA sequencing on 21 well-characterized isolates to examine how genetic variation contributes to gene expression differences and to link these differences to phenotypic traits. adapts primarily through clonal evolution, and yet hierarchical clustering of gene expression profiles in this set of isolates did not reproduce their phylogenetic relationship.

Adaptation to the dietary sugar D-tagatose via genome instability in polyploid Candida albicans cells.

The opportunistic fungal pathogen Candida albicans undergoes an unusual parasexual cycle wherein diploid cells mate to form tetraploid cells that can generate genetically diverse progeny via a nonmeiotic program of chromosome loss. The genetic diversity afforded by parasex impacts clinically relevant features including drug resistance and virulence, and yet the factors influencing genome instability in C. albicans are not well defined.

Comparative genomics of white and opaque cell states supports an epigenetic mechanism of phenotypic switching in Candida albicans.

Several Candida species can undergo a heritable and reversible transition from a 'white' state to a mating proficient 'opaque' state. This ability relies on highly interconnected transcriptional networks that control cell-type-specific gene expression programs over multiple generations. Candida albicans, the most prominent pathogenic Candida species, provides a well-studied paradigm for the white-opaque transition.

Epigenetic cell fate in Candida albicans is controlled by transcription factor condensates acting at super-enhancer-like elements.

Cell identity in eukaryotes is controlled by transcriptional regulatory networks that define cell-type-specific gene expression. In the opportunistic fungal pathogen Candida albicans, transcriptional regulatory networks regulate epigenetic switching between two alternative cell states, 'white' and 'opaque', that exhibit distinct host interactions. In the present study, we reveal that the transcription factors (TFs) regulating cell identity contain prion-like domains (PrLDs) that enable liquid-liquid demixing and the formation of phase-separated condensates.

Corrigendum: Genetic Modification of Closely Related Candida Species.

[This corrects the article DOI: 10.3389/fmicb.2019.

The Impact of Gene Dosage and Heterozygosity on The Diploid Pathobiont .

is a fungal species that can colonize multiple niches in the human host where it can grow either as a commensal or as an opportunistic pathogen. The genome of has long been of considerable interest, given that it is highly plastic and can undergo a wide variety of alterations. These changes play a fundamental role in determining traits and have been shown to enable adaptation both to the host and to antifungal drugs.

A 'parameiosis' drives depolyploidization and homologous recombination in Candida albicans.

Meiosis is a conserved tenet of sexual reproduction in eukaryotes, yet this program is seemingly absent from many extant species. In the human fungal pathogen Candida albicans, mating of diploid cells generates tetraploid products that return to the diploid state via a non-meiotic process of depolyploidization known as concerted chromosome loss (CCL). Here, we report that recombination rates are more than three orders of magnitude higher during CCL than during normal mitotic growth.