scholarly journals Saccharomyces cerevisiae S288C Has a Mutation in FL08, a Gene Required for Filamentous Growth

Genetics ◽  
1996 ◽  
Vol 144 (3) ◽  
pp. 967-978 ◽  
Author(s):  
Haoping Liu ◽  
Cora Ann Styles ◽  
Gerald R Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nonsense Mutation ◽  
Laboratory Strain ◽  
Filamentous Growth ◽  
Invasive Growth ◽  
Baker's Yeast ◽  
Standard Laboratory ◽  
Dimorphic Transition ◽  
Yeast Form ◽  
Pseudohyphal Growth

Abstract Diploid strains of baker's yeast Saccharomyces cermisiae can grow in a cellular yeast form or in filaments called pseudohyphae. This dimorphic transition from yeast to pseudohyphae is induced by starvation for nitrogen. Not all laboratory strains are capable of this dimorphic switch; many grow only in the yeast form and fail to form pseudohyphae when starved for nitrogen. Analysis of the standard laboratory strain S288C shows that this defect in dimorphism results from a nonsense mutation in the FL08 gene. This defect in FL08 blocks pseudohyphal growth in diploids, haploid invasive growth, and flocculation. Since feral strains of S. cerevisiae are dimorphic and have a functional FL08 gene, we suggest that the fl08 mutation was selected during laboratory cultivation.

scholarly journals Dissection of Filamentous Growth by Transposon Mutagenesis in Saccharomyces cerevisiae

Genetics ◽  
1997 ◽  
Vol 145 (3) ◽  
pp. 671-684 ◽  
Author(s):  
Hans-Ulrich Mösch ◽  
Gerald R Fink
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Signaling Pathway ◽  
Filamentous Growth ◽  
Invasive Growth ◽  
Cell Morphogenesis ◽  
Phenotypic Analysis ◽  
Cellular Processes ◽  
Evolutionarily Conserved ◽  
Mutant Strains ◽  
Bud Site

Diploid Saccharomyces cerevisiae strains starved for nitrogen undergo a developmental transition from growth as single yeast form (YF) cells to a multicellular form consisting of filaments of pseudohyphal (PH) cells. Filamentous growth is regulated by an evolutionarily conserved signaling pathway that includes the small GTP-binding proteins Ras2p and Cdc42p, the protein kinases Ste20p, Ste11p and Ste7p, and the transcription factor Ste12p. Here, we designed a genetic screen for mutant strains defective for filamentous growth (dfg) to identify novel targets of the filamentation signaling pathway, and we thereby identified 16 different genes, CDC39, STE12, TEC1, WH13, NAB1, DBR1, CDC55, SRV2, TPM1, SPA2, BNI1, DFG5, DFG9, DFG10, BUD8 and DFG16, mutations that block filamentous growth. Phenotypic analysis of dfg mutant strains genetically dissects filamentous growth into the cellular processes of signal transduction, bud site selection, cell morphogenesis and invasive growth. Epistasis tests between dfg mutant alleles and dominant activated alleles of the RAS2 and STE11 genes, RAS2Val19 and STE11-4, respectively, identify putative targets for the filamentation signaling pathway. Several of the genes described here have homologues in filamentous fungi, where they also regulate fungal development.

scholarly journals Characterization of the Saccharomyces cerevisiae Fol1 Protein: Starvation for C1 Carrier Induces Pseudohyphal Growth

2004 ◽  
Vol 15 (8) ◽  
pp. 3811-3828 ◽  
Author(s):  
Ulrich Güldener ◽  
Gabriele J. Koehler ◽  
Christoph Haussmann ◽  
Adelbert Bacher ◽  
Jörn Kricke ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Folinic Acid ◽  
Enzyme Activities ◽  
De Novo ◽  
Essential Gene ◽  
Enzymatic Reactions ◽  
Invasive Growth ◽  
Pseudohyphal Growth ◽  
Vitamin B9 ◽  
Rich Media

Tetrahydrofolate (vitamin B9) and its folate derivatives are essential cofactors in one-carbon (C1) transfer reactions and absolutely required for the synthesis of a variety of different compounds including methionine and purines. Most plants, microbial eukaryotes, and prokaryotes synthesize folate de novo. We have characterized an important enzyme in this pathway, the Saccharomyces cerevisiae FOL1 gene. Expression of the budding yeast gene FOL1 in Escherichia coli identified the folate biosynthetic enzyme activities dihydroneopterin aldolase (DHNA), 7,8-dihydro-6-hydroxymethylpterin-pyrophosphokinase (HPPK), and dihydropteroate synthase (DHPS). All three enzyme activities were also detected in wild-type yeast strains, whereas fol1Δ deletion strains only showed background activities, thus demonstrating that Fol1p catalyzes three sequential steps of the tetrahydrofolate biosynthetic pathway and thus is the central enzyme of this pathway, which starting from GTP consists of seven enzymatic reactions in total. Fol1p is exclusively localized to mitochondria as shown by fluorescence microscopy and immune electronmicroscopy. FOL1 is an essential gene and the nongrowth phenotype of the fol1 deletion leads to a recessive auxotrophy for folinic acid (5′-formyltetrahydrofolate). Growth of the fol1Δ deletion strain on folinic acid–supplemented rich media induced a dimorphic switch with haploid invasive and filamentous pseudohyphal growth in the presence of glucose and ammonium, which are known suppressors of filamentous and invasive growth. The invasive growth phenotype induced by the depletion of C1 carrier is dependent on the transcription factor Ste12p and the flocullin/adhesin Flo11p, whereas the filamentation phenotype is independent of Ste12p, Tec1p, Phd1p, and Flo11p, suggesting other signaling pathways as well as other adhesion proteins.

scholarly journals Aggregate Filamentous Growth Responses in Yeast

mSphere ◽  
2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Jacky Chow ◽  
Heather M. Dionne ◽  
Aditi Prabhakar ◽  
Amit Mehrotra ◽  
Jenn Somboonthum ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Signaling Pathways ◽  
Budding Yeast ◽  
Filamentous Growth ◽  
Fungal Species ◽  
Fungal Pathogenesis ◽  
Invasive Growth ◽  
Content Type ◽  
Secreted Enzymes

ABSTRACTMany fungal species, including pathogens, undergo a morphogenetic response called filamentous growth, where cells differentiate into a specialized cell type to promote nutrient foraging and surface colonization. Despite the fact that filamentous growth is required for virulence in some plant and animal pathogens, certain aspects of this behavior remain poorly understood. By examining filamentous growth in the budding yeastSaccharomyces cerevisiaeand the opportunistic pathogenCandida albicans, we identify responses where cells undergo filamentous growth in groups of cells or aggregates. InS. cerevisiae, aggregate invasive growth was regulated by signaling pathways that control normal filamentous growth. These pathways promoted aggregation in part by fostering aspects of microbial cooperation. For example, aggregate invasive growth required cellular contacts mediated by the flocculin Flo11p, which was produced at higher levels in aggregates than cells undergoing regular invasive growth. Aggregate invasive growth was also stimulated by secreted enzymes, like invertase, which produce metabolites that are shared among cells. Aggregate invasive growth was also induced by alcohols that promote density-dependent filamentous growth in yeast. Aggregate invasive growth also required highly polarized cell morphologies, which may affect the packing or organization of cells. A directed selection experiment for aggregating phenotypes uncovered roles for the fMAPK and RAS pathways, which indicates that these pathways play a general role in regulating aggregate-based responses in yeast. Our study extends the range of responses controlled by filamentation regulatory pathways and has implications in understanding aspects of fungal biology that may be relevant to fungal pathogenesis.IMPORTANCEFilamentous growth is a fungal morphogenetic response that is critical for virulence in some fungal species. Many aspects of filamentous growth remain poorly understood. We have identified an aspect of filamentous growth in the budding yeastSaccharomyces cerevisiaeand the human pathogenCandida albicanswhere cells behave collectively to invade surfaces in aggregates. These responses may reflect an extension of normal filamentous growth, as they share the same signaling pathways and effector processes. Aggregate responses may involve cooperation among individual cells, because aggregation was stimulated by cell adhesion molecules, secreted enzymes, and diffusible molecules that promote quorum sensing. Our study may provide insights into the genetic basis of collective cellular responses in fungi. The study may have ramifications in fungal pathogenesis, in situations where collective responses occur to promote virulence.

scholarly journals Pseudohyphal Growth of Cryptococcus neoformans Is a Reversible Dimorphic Transition in Response to Ammonium That Requires Amt1 and Amt2 Ammonium Permeases

2012 ◽  
Vol 11 (11) ◽  
pp. 1391-1398 ◽  
Author(s):  
Soo Chan Lee ◽  
Sujal Phadke ◽  
Sheng Sun ◽  
Joseph Heitman
Keyword(s):  
Cryptococcus Neoformans ◽  
Growth Pattern ◽  
Yeast Cells ◽  
Invasive Growth ◽  
Sole Nitrogen Source ◽  
Genetic Event ◽  
Content Type ◽  
Dimorphic Transition ◽  
Pseudohyphal Growth ◽  
Human Infections

ABSTRACTCryptococcus neoformansis a human-pathogenic basidiomycete that commonly infects HIV/AIDS patients to cause meningoencephalitis (7, 19).C. neoformansgrows as a budding yeast during vegetative growth or as hyphae during sexual reproduction. Pseudohyphal growth ofC. neoformanshas been observed rarely during murine and human infections but frequently during coculture with amoeba; however, the genetics underlying pseudohyphal growth are largely unknown. Our studies found thatC. neoformansdisplays pseudohyphal growth under nitrogen-limiting conditions, especially when a small amount of ammonium is available as a sole nitrogen source. Pseudohyphal growth was observed withCryptococcus neoformansserotypes A and D andCryptococcus gattii. C. neoformanspseudohyphae bud to produce yeast cells and normal smooth hemispherical colonies when transferred to complete media, indicating that pseudohyphal growth is a conditional developmental stage. Subsequent analysis revealed that two ammonium permeases encoded by theAMT1andAMT2genes are required for pseudohyphal growth. Bothamt1andamt2mutants are capable of forming pseudohyphae; however,amt1 amt2double mutants do not form pseudohyphae. Interestingly,C. gattiipseudohypha formation is irreversible and involves a RAM pathway mutation that drives pseudohyphal development. We also found that pseudohyphal growth is related to the invasive growth into the medium. These results demonstrate that pseudohyphal growth is a common reversible growth pattern inC. neoformansbut a mutational genetic event inC. gattiiand provide new insights into understanding pseudohyphal growth ofCryptococcus.

scholarly journals New Aspects of Invasive Growth Regulation Identified by Functional Profiling of MAPK Pathway Targets in Saccharomyces cerevisiae

Genetics ◽  
2020 ◽  
Vol 216 (1) ◽  
pp. 95-116 ◽  
Author(s):  
Matthew D. Vandermeulen ◽  
Paul J. Cullen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Adhesion ◽  
Stress Responses ◽  
Cellular Response ◽  
Growth Regulation ◽  
Mapk Pathway ◽  
Filamentous Growth ◽  
Invasive Growth ◽  
Link Type ◽  
Mapk Pathways

MAPK pathways are drivers of morphogenesis and stress responses in eukaryotes. A major function of MAPK pathways is the transcriptional induction of target genes, which produce proteins that collectively generate a cellular response. One approach to comprehensively understand how MAPK pathways regulate cellular responses is to characterize the individual functions of their transcriptional targets. Here, by examining uncharacterized targets of the MAPK pathway that positively regulates filamentous growth in Saccharomyces cerevisiae (fMAPK pathway), we identified a new role for the pathway in negatively regulating invasive growth. Specifically, four targets were identified that had an inhibitory role in invasive growth: RPI1, RGD2, TIP1, and NFG1/YLR042c. NFG1 was a highly induced unknown open reading frame that negatively regulated the filamentous growth MAPK pathway. We also identified SFG1, which encodes a transcription factor, as a target of the fMAPK pathway. Sfg1p promoted cell adhesion independently from the fMAPK pathway target and major cell adhesion flocculin Flo11p, by repressing genes encoding presumptive cell-wall-degrading enzymes. Sfg1p also contributed to FLO11 expression. Sfg1p and Flo11p regulated different aspects of cell adhesion, and their roles varied based on the environment. Sfg1p also induced an elongated cell morphology, presumably through a cell-cycle delay. Thus, the fMAPK pathway coordinates positive and negative regulatory proteins to fine-tune filamentous growth resulting in a nuanced response. Functional analysis of other pathways’ targets may lead to a more comprehensive understanding of how signaling cascades generate biological responses.

scholarly journals The Mitotic Cyclins Clb2p and Clb4p Affect Morphogenesis inCandida albicans

2005 ◽  
Vol 16 (7) ◽  
pp. 3387-3400 ◽  
Author(s):  
Eric S. Bensen ◽  
Andres Clemente-Blanco ◽  
Kenneth R. Finley ◽  
Jaime Correa-Bordes ◽  
Judith Berman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Filamentous Growth ◽  
Mitotic Exit ◽  
Cycle Progression ◽  
Yeast Form ◽  
Cell Cycle Machinery ◽  
Incandida Albicans

The ability of Candida albicans to switch cellular morphologies is crucial for its ability to cause infection. Because the cell cycle machinery participates in Saccharomyces cerevisiae filamentous growth, we characterized in detail the two C. albicans B-type cyclins, CLB2 and CLB4, to better understand the molecular mechanisms that underlie the C. albicans morphogenic switch. Both Clb2p and Clb4p levels are cell cycle regulated, peaking at G2/M and declining before mitotic exit. On hyphal induction, the accumulation of the G1 cyclin Cln1p was prolonged, whereas the accumulation of both Clb proteins was delayed when compared with yeast form cells, indicating that CLB2 and CLB4 are differentially regulated in the two morphologies and that the dynamics of cyclin appearance differs between yeast and hyphal forms of growth. Clb2p-depleted cells were inviable and arrested with hyper-elongated projections containing two nuclei, suggesting that Clb2p is not required for entry into mitosis. Unlike Clb2p-depleted cells, Clb4p-depleted cells were viable and formed constitutive pseudohyphae. Clb proteins lacking destruction box domains blocked cell cycle progression resulting in the formation of long projections, indicating that both Clb2p and Clb4p must be degraded before mitotic exit. In addition, overexpression of either B-type cyclin reduced the extent of filamentous growth. Taken together, these data indicate that Clb2p and Clb4p regulate C. albicans morphogenesis by negatively regulating polarized growth.

scholarly journals Spt3 Plays Opposite Roles in Filamentous Growth in Saccharomyces cerevisiae and Candida albicans and Is Required for C. albicans Virulence

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 509-519
Author(s):  
Lisa Laprade ◽  
Victor L Boyartchuk ◽  
William F Dietrich ◽  
Fred Winston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Albicans ◽  
Filamentous Growth ◽  
Growth Defect ◽  
Invasive Growth ◽  
Pathogenic Yeast ◽  
Normal Expression

Abstract Spt3 of Saccharomyces cerevisiae is required for the normal transcription of many genes in vivo. Past studies have shown that Spt3 is required for both mating and sporulation, two events that initiate when cells are at G1/START. We now show that Spt3 is needed for two other events that begin at G1/START, diploid filamentous growth and haploid invasive growth. In addition, Spt3 is required for normal expression of FLO11, a gene required for filamentous growth, although this defect is not the sole cause of the spt3Δ/spt3Δ filamentous growth defect. To extend our studies of Spt3's role in filamentous growth to the pathogenic yeast Candida albicans, we have identified the C. albicans SPT3 gene and have studied its role in C. albicans filamentous growth and virulence. Surprisingly, C. albicans spt3Δ/spt3Δ mutants are hyperfilamentous, the opposite phenotype observed for S. cerevisiae spt3Δ/spt3Δ mutants. Furthermore, C. albicans spt3Δ/spt3Δ mutants are avirulent in mice. These experiments demonstrate that Spt3 plays important but opposite roles in filamentous growth in S. cerevisiae and C. albicans.

scholarly journals Variation in filamentous growth and response to quorum-sensing compounds in environmental isolates of Saccharomyces cerevisiae

2019 ◽  
Author(s):  
B. Adam Lenhart ◽  
Brianna Meeks ◽  
Helen A. Murphy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quorum Sensing ◽  
Natural Populations ◽  
Filamentous Growth ◽  
West African ◽  
Natural Genetic Variation ◽  
Pseudohyphal Growth ◽  
Natural Isolates ◽  
Candidate Loci ◽  
Computational Image Analysis

AbstractIn fungi, filamentous growth is a major developmental transition that occurs in response to environmental cues. In diploid Saccharomyces cerevisiae, it is known as pseudohyphal growth and presumed to be a foraging mechanism. Rather than normal unicellular growth, multicellular filaments composed of elongated, attached cells spread over and into surfaces. This morphogenetic switch can be induced through quorum sensing with the aromatic alcohols phenylethanol and tryptophol. Most research investigating pseudohyphal growth has been conducted in a single lab background, Σ1278b. To investigate the natural variation in this phenotype and its induction, we assayed the diverse 100-genomes collection of environmental S. cerevisiae isolates. Using computational image analysis, we quantified the production of pseudohyphae and observed a large amount of variation. Unlike ecological niche, population membership was associated with pseudohyphal growth, with the West African population having the most. Surprisingly, most strains showed little or no response to exogenous phenylethanol or tryptophol. We also investigated the amount of natural genetic variation in pseudohyphal growth using a mapping population derived from a single, highly-heterozygous clinical isolate that contained as much phenotypic variation as the environmental panel. A bulk-segregant analysis uncovered five major peaks with candidate loci that have been implicated in the Σ1278b background. Our results indicate that the filamentous growth response is a generalized, highly variable phenotype in natural populations, while response to quorum sensing molecules is surprisingly rare. These findings highlight the importance of coupling studies in tractable lab strains with natural isolates in order to understand the relevance and distribution of well-studied traits.

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