Morphogenetic Transformation of Fungi

Shepherd, Maxwell G.

doi:10.1007/978-1-4612-3730-3_8

Cited by 31 publications

(16 citation statements)

References 113 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The identification of dimorphism genes from pathogenic fungi will be interesting because dimorphism appears to be involved in the virulence of several fungal pathogens of animals and plants (7,67). For instance, the unicellular growth mode of the human pathogen Histoplasma capsulatum is associated with disease, while the filamentous phase appears to be avirulent (49,50).…”

Section: Agcgtcgcacgtccaaataaccttaaatcaatagcagcagcgtcaccaacagtgacagcamentioning

confidence: 99%

Induction of pseudohyphal growth by overexpression of PHD1, a Saccharomyces cerevisiae gene related to transcriptional regulators of fungal development.

1994

View full text Add to dashboard Cite

When starved for nitrogen, AMTa/AMTo cells of the budding yeast Saccharomyces cerevisiae undergo a dimorphic transition to pseudohyphal growth. A visual genetic screen, called PHD (pseudohyphal determinant), for S. cerevisiae pseudohyphal growth mutants was developed. The PHD screen was used to identify seven S. cerevisiae genes that when overexpressed in AMTa/MAMTot cells growing on nitrogen starvation medium cause precocious and unusually vigorous pseudohyphal growth. PHDI, a gene whose overexpression induced invasive pseudohyphal growth on a nutritionally rich medium, was characterized. PHDI maps to chromosome XI and is predicted to encode a 366-amino-acid protein. PHD1 has a SWI4-and MBP1-like DNA binding motif that is 73% identical over 100 amino acids to a region ofAspergillus nidulans StuA. StuA regulates two pseudohyphal growth-like cell divisions during conidiophore morphogenesis. Epitope-tagged PHD1 was localized to the nucleus by indirect immunofluorescence. These facts suggest that PHD1 may function as a transcriptional regulatory protein. Overexpression ofPHDI in wild-type haploid strains does not induce pseudohyphal growth. Interestingly, PHDI overexpression enhances pseudohyphal growth in a haploid strain that has the diploid polar budding pattern because of a mutation in the BUD4 gene. In addition, wild-type diploid strains lacking PHDI undergo pseudohyphal growth when starved for nitrogen. The possible functions of PHDI in pseudohyphal growth and the uses of the PHD screen to identify morphogenetic regulatory genes from heterologous organisms are discussed.

show abstract

Section: Agcgtcgcacgtccaaataaccttaaatcaatagcagcagcgtcaccaacagtgacagcamentioning

confidence: 99%

Induction of pseudohyphal growth by overexpression of PHD1, a Saccharomyces cerevisiae gene related to transcriptional regulators of fungal development.

1994

View full text Add to dashboard Cite

show abstract

“…Understanding the mechanisms that regulate these events is of major interest because of their implications in fungal pathogenesis and cell differentiation ; studies performed in Saccharomyces cerevisiae, C. albicans and Ustilago maydis have revealed that important differences in how dimorphism is regulated exist among different yeast species. Accordingly, additional studies are required in other organisms to acquire a more complete understanding of the overall phenomenon of fungal dimorphism (Odds, 1988 ;Shepherd, 1988 ;Maresca & Kobayashi, 1989 ;Gow, 1994 ;Banuett, 1995 ;Lo et al, 1997 ;Madhani & Fink, 1998 ;Bolker, 2001). Due to its ability to alternate between a unicellular yeast form and different filamentous forms (hyphae and pseudohyphae), its amenability to genetic and molecular biological analyses and its ability to reproduce sexually, the yeast Yarrowia lipolytica has emerged as an excellent alternative model for the investigation of the molecular aspects of fungal morphogenesis (Enderlin & Ogrydziak, 1994 ;Barth & Gaillardin, 1996 ;Torres-Guzman & Dominguez, 1997 ;Hurtado & Rachubinski, 1999 ;Hurtado et al, 2000 ;Richard et al, 2001 ;Szabo, 2001).…”

Section: Introductionmentioning

confidence: 99%

YlBMH1 encodes a 14-3-3 protein that promotes filamentous growth in the dimorphic yeast Yarrowia lipolytica a aThe GenBank accession numbers for the YlBMH1 and YlBMH2 sequences reported in this study are AY090661 and AY090662, respectively.

Hurtado

Rachubinski

2002

Microbiology

View full text Add to dashboard Cite

Most pathogenic fungi have the ability to alternate between a unicellular yeast form and different filamentous forms (hyphae and pseudohyphae). This attribute is generally regarded as an important virulence factor and has also attracted attention because of its implications in the study of eukaryotic cell differentiation. To identify genes that are involved in the regulation of these events, chemical mutagenesis of the dimorphic yeast Yarrowia lipolytica was performed and morphological mutants that were unable to form hyphal cells were isolated. Screening of a Y. lipolytica genomic DNA library for genes able to complement this defect led to the isolation of YlBMH1, a gene encoding a 14-3-3 protein and whose transcription levels are increased during the yeast-tohypha transition. Remarkably, overexpression of YlBMH1 was able to enhance pseudohyphae formation in a strain lacking functional YlRAC1 but caused no visible effects in ∆mhy1 and ∆bem1 cells, thus suggesting that YlBMH1 is involved in the regulation of both hyphal and pseudohyphal growth in Y. lipolytica. The identification of YlBMH2, a gene encoding a second 14-3-3 protein (YlBmh2p) that contains a 19 aa insertion absent in all other members of the 14-3-3 family, is also reported. Differently from YlBMH1, the transcription levels of YlBMH2 do not show any apparent variation during the induction of hyphal growth, and its overexpression has no effects on cells lacking functional MHY1, YlRAC1 or YlBEM1. Taken together, these observations suggest that, in spite of their high conservation, YlBmh1p and YlBmh2p have different cellular functions.

show abstract

“…The yeast-to-hypha morphological transition (dimorphism) is typical of many pathogenic fungi (62). The dimorphic transition is a freely reversible process that can be induced by changes in many parameters (56).…”

mentioning

confidence: 99%

HOY1, a Homeo Gene Required for Hyphal Formation inYarrowia lipolytica

Torres-Guzmán

Domínguez

1997

Molecular and Cellular Biology

View full text Add to dashboard Cite

The dimorphic fungus Yarrowia lipolytica grows to form hyphae either in rich media or in media with GlcNAc as a carbon source. A visual screening, called FIL (filamentation minus), for Y. lipolytica yeast growth mutants has been developed. The FIL screen was used to identify three Y. lipolytica genes that abolish hypha formation in all media assayed. Y. lipolytica HOY1, a gene whose deletion prevents the yeast-hypha transition both in liquid and solid media, was characterized. HOY1 is predicted to encode a 509-amino-acid protein with a homeodomain homologous to that found in the chicken Hox4.8 gene. Analysis of the protein predicts a nuclear location. These observations suggest that Hoy1p may function as a transcriptional regulatory protein. In disrupted strains, reintroduction of HOY1 restored the capacity for hypha formation. Northern blot hybridization revealed the HOY1 transcript to be approximately 1.6 kb. Expression of this gene was detected when Y. lipolytica grew as a budding yeast, but an increase in its expression was observed by 1 h after cells had been induced to form hyphae. The possible functions of HOY1 in hyphal growth and the uses of the FIL screen to identify morphogenetic regulatory genes from heterologous organisms are discussed.The yeast-to-hypha morphological transition (dimorphism) is typical of many pathogenic fungi (62). The dimorphic transition is a freely reversible process that can be induced by changes in many parameters (56). Much attention has been focused on Candida albicans as a model for analyzing dimorphism because it is the most frequently isolated fungal pathogen in humans. However, although several groups have reported the isolation of mutants which persist in either the yeast (10) or hyphal (21, 30) form, analysis of these mutants is hampered by the difficulties inherent to genetic manipulations of this asexual diploid organism.Two approaches have been successfully used to carry out the analysis of dimorphism. With one of them, differential hybridization screening (7), several genes that are differentially expressed during morphogenesis have been isolated in C. albicans (i.e., ECE1, expressed in association with cell elongation, and PHR1, which is differentially regulated in response to the pH of the growth medium). Deletion of PHR1 results in a pH-conditional defect in morphogenesis (59).The second approach consists of cloning Candida homologs of Saccharomyces cerevisiae genes known to regulate pseudofilamentous growth. Under conditions of nutrient limitation (i.e., nitrogen starvation), S. cerevisiae undergoes a dimorphic transition to growth of pseudohyphae, linear chains of elongated cells in which the daughters remain attached to the mothers (23, 24). In this context, several C. albicans genes that are members of a Candida map kinase (MAPK) cascade, i.e., CPH1 (40) or ACPR (43), HST7 (11), and CST20 (36, 39), have been isolated by complementation of the corresponding Saccharomyces mutants, i.e., STE12, STE7, and STE20, respectively (11,36,39,40,43). When C. albicans st...

show abstract

Morphogenetic Transformation of Fungi

Cited by 31 publications

References 113 publications

Induction of pseudohyphal growth by overexpression of PHD1, a Saccharomyces cerevisiae gene related to transcriptional regulators of fungal development.

Induction of pseudohyphal growth by overexpression of PHD1, a Saccharomyces cerevisiae gene related to transcriptional regulators of fungal development.

YlBMH1 encodes a 14-3-3 protein that promotes filamentous growth in the dimorphic yeast Yarrowia lipolytica a aThe GenBank accession numbers for the YlBMH1 and YlBMH2 sequences reported in this study are AY090661 and AY090662, respectively.

HOY1, a Homeo Gene Required for Hyphal Formation inYarrowia lipolytica

Contact Info

Product

Resources

About