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.

Genetic Analysis Reveals That FLO11 Upregulation and Cell Polarization Independently Regulate Invasive Growth in Saccharomyces cerevisiae

Genetics ◽  
2000 ◽  
Vol 156 (3) ◽  
pp. 1005-1023 ◽  
Author(s):  
Sean P Palecek ◽  
Archita S Parikh ◽  
Stephen J Kron
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Polarization ◽  
Signaling Cascades ◽  
Invasive Growth ◽  
Map Kinase Cascade ◽  
Mutant Strains ◽  
Kinase Cascade ◽  
A Cell ◽  
Agar Surface ◽  
Bud Site

Abstract Under inducing conditions, haploid Saccharomyces cerevisiae perform a dimorphic transition from yeast-form growth on the agar surface to invasive growth, where chains of cells dig into the solid growth medium. Previous work on signaling cascades that promote agar invasion has demonstrated upregulation of FLO11, a cell-surface flocculin involved in cell-cell adhesion. We find that increasing FLO11 transcription is sufficient to induce both invasive and filamentous growth. A genetic screen for repressors of FLO11 isolated mutant strains that dig into agar (dia) and identified mutations in 35 different genes: ELM1, HSL1, HSL7, BUD3, BUD4, BUD10, AXL1, SIR2, SIR4, BEM2, PGI1, GND1, YDJ1, ARO7, GRR1, CDC53, HSC82, ZUO1, ADH1, CSE2, GCR1, IRA1, MSN5, SRB8, SSN3, SSN8, BPL1, GTR1, MED1, SKN7, TAF25, DIA1, DIA2, DIA3, and DIA4. Indeed, agar invasion in 20 dia mutants requires upregulation of the endogenous FLO11 promoter. However, 13 mutants promote agar invasion even with FLO11 clamped at a constitutive low-expression level. These FLO11 promoter-independent dia mutants establish distinct invasive growth pathways due to polarized bud site selection and/or cell elongation. Epistasis with the STE MAP kinase cascade and cytokinesis/budding checkpoint shows these pathways are targets of DIA genes that repress agar invasion by FLO11 promoter-dependent and -independent mechanisms, respectively.

scholarly journals A steep phosphoinositide bis-phosphate gradient forms during fungal filamentous growth

2012 ◽  
Vol 198 (4) ◽  
pp. 711-730 ◽  
Author(s):  
Aurélia Vernay ◽  
Sébastien Schaub ◽  
Isabelle Guillas ◽  
Martine Bassilana ◽  
Robert A. Arkowitz
Keyword(s):  
Long Range ◽  
Membrane Lipids ◽  
Pathogenic Fungus ◽  
Filamentous Growth ◽  
Asymmetric Distribution ◽  
Cell Morphogenesis ◽  
Membrane Diffusion ◽  
Cellular Processes ◽  
Human Pathogenic Fungus

Membrane lipids have been implicated in many critical cellular processes, yet little is known about the role of asymmetric lipid distribution in cell morphogenesis. The phosphoinositide bis-phosphate PI(4,5)P2 is essential for polarized growth in a range of organisms. Although an asymmetric distribution of this phospholipid has been observed in some cells, long-range gradients of PI(4,5)P2 have not been observed. Here, we show that in the human pathogenic fungus Candida albicans a steep, long-range gradient of PI(4,5)P2 occurs concomitant with emergence of the hyphal filament. Both sufficient PI(4)P synthesis and the actin cytoskeleton are necessary for this steep PI(4,5)P2 gradient. In contrast, neither microtubules nor asymmetrically localized mRNAs are critical. Our results indicate that a gradient of PI(4,5)P2, crucial for filamentous growth, is generated and maintained by the filament tip–localized PI(4)P-5-kinase Mss4 and clearing of this lipid at the back of the cell. Furthermore, we propose that slow membrane diffusion of PI(4,5)P2 contributes to the maintenance of such a gradient.

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 Hsl7p, a negative regulator of Ste20p protein kinase in the Saccharomyces cerevisiae filamentous growth-signaling pathway

1999 ◽  
Vol 96 (15) ◽  
pp. 8522-8527 ◽  
Author(s):  
A. Fujita ◽  
A. Tonouchi ◽  
T. Hiroko ◽  
F. Inose ◽  
T. Nagashima ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Kinase ◽  
Signaling Pathway ◽  
Filamentous Growth ◽  
Negative Regulator

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 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 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 Effects of mutations in the Saccharomyces cerevisiae RNA14, RNA15, and PAP1 genes on polyadenylation in vivo.

1995 ◽  
Vol 15 (12) ◽  
pp. 6979-6986 ◽  
Author(s):  
E Mandart ◽  
R Parker
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mrna Degradation ◽  
Gene Products ◽  
Polymerase Gene ◽  
Cellular Processes ◽  
Mutant Strains ◽  
Cleavage And Polyadenylation ◽  
A Site

The RNA14 and RNA15 gene products have been implicated in a variety of cellular processes. Mutations in these genes lead to faster decay of some mRNAs and yield extracts that are deficient in cleavage and polyadenylation in vitro. These results suggest that the RNA14 and RNA15 gene products may be involved in both adenylation and deadenylation in vivo. To explore the roles of these gene products in vivo, we examined the site of adenylation and the rate of deadenylation for individual mRNAs in rna14 and rna15 mutant strains. We observed that the rates of deadenylation are not affected by lesions in either the RNA14 or the RNA15 gene. This result suggests that the proteins encoded by these genes are not involved in regulation of the deadenylation rate. In contrast, we observed that the site of adenylation for the ACT1 transcript can be altered in these mutants. Interestingly, we also observed that mutation of the poly(A) polymerase gene altered the site of ACT1 polyadenylation. These observations suggest that the RNA14, RNA15, and PAP1 proteins are involved in poly(A) site choice. This alteration in poly(A) site choice in the rna14 mutant can be corrected by the ssm4 suppressor, indicating that this suppression acts at the level of polyadenylation and not by slowing mRNA degradation.

scholarly journals Differential Requirement of SAGA Subunits for Mot1p and Taf1p Recruitment in Gene Activation

2005 ◽  
Vol 25 (12) ◽  
pp. 4863-4872 ◽  
Author(s):  
Chris J. C. van Oevelen ◽  
Hetty A. A. M. van Teeffelen ◽  
H. T. Marc Timmers
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Double Mutant ◽  
Gene Activation ◽  
Transcription Activation ◽  
Tata Binding Protein ◽  
Genetic Interactions ◽  
Hexose Transporter ◽  
Phenotypic Analysis ◽  
Transcription Factor Complexes ◽  
Mutant Strains

ABSTRACT Transcription activation in yeast (Saccharomyces cerevisiae) involves ordered recruitment of transcription factor complexes, such as TFIID, SAGA, and Mot1p. Previously, we showed that both Mot1p and Taf1p are recruited to the HXT2 and HXT4 genes, which encode hexose transporter proteins. Here, we show that SAGA also binds to the HXT2 and HXT4 promoters and plays a pivotal role in the recruitment of Mot1p and Taf1p. The deletion of either SPT3 or SPT8 reduces Mot1p binding to HXT2 and HXT4. Surprisingly, the deletion of GCN5 reduces Taf1p binding to both promoters. When GCN5 is deleted in spt3Δ or spt8Δ strains, neither Mot1p nor Taf1p binds, and this results in a diminished recruitment of TATA binding protein and polymerase II to the HXT4 but not the HXT2 promoter. This is reflected by the SAGA-dependent expression of HXT4. In contrast, SAGA-independent induction of HXT2 suggests a functional redundancy with other factors. A functional interplay of different SAGA subunits with Mot1p and Taf1p was supported by phenotypic analysis of MOT1 SAGA or TAF1/SAGA double mutant strains, which revealed novel genetic interactions between MOT1 and SPT8 and between TAF1 and GCN5. In conclusion, our data demonstrate functional links between SAGA, Mot1p, and TFIID in HXT gene regulation.

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