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Romano J, Nimrod G, Ben-Tal N, Shadkchan Y, Baruch K, Sharon H, Osherov N. Disruption of the Aspergillus fumigatus ECM33 homologue results in rapid conidial germination, antifungal resistance and hypervirulence. MICROBIOLOGY-SGM 2006; 152:1919-1928. [PMID: 16804168 DOI: 10.1099/mic.0.28936-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The ECM33/SPS2 family of glycosylphosphatidylinositol-anchored proteins plays an important role in maintaining fungal cell wall integrity and virulence. However, the precise molecular role of these proteins is unknown. In this work, AfuEcm33, the gene encoding the ECM33 homologue in the important pathogenic fungus Aspergillus fumigatus, has been cloned and its function analysed. It is shown that disruption of AfuEcm33 results in rapid conidial germination, increased cell-cell adhesion, resistance to the antifungal agent caspofungin and increased virulence in an immunocompromised mouse model for disseminated aspergillosis. These results suggest that the protein encoded by AfuEcm33 is involved in key aspects of cell wall morphogenesis and plays an important role in A. fumigatus virulence.
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Affiliation(s)
- Jacob Romano
- Department of Human Microbiology, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel
| | - Guy Nimrod
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel
| | - Nir Ben-Tal
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel
| | - Yona Shadkchan
- Department of Human Microbiology, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel
| | - Koti Baruch
- Department of Human Microbiology, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel
| | - Haim Sharon
- Department of Human Microbiology, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel
| | - Nir Osherov
- Department of Human Microbiology, Sackler School of Medicine, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel
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202
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Chabane S, Sarfati J, Ibrahim-Granet O, Du C, Schmidt C, Mouyna I, Prevost MC, Calderone R, Latgé JP. Glycosylphosphatidylinositol-anchored Ecm33p influences conidial cell wall biosynthesis in Aspergillus fumigatus. Appl Environ Microbiol 2006; 72:3259-67. [PMID: 16672465 PMCID: PMC1472355 DOI: 10.1128/aem.72.5.3259-3267.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ECM33 encodes a glycosylphosphatidylinositol-anchored protein whose orthologs in yeast are essential for sporulation. Aspergillus fumigatus Ecm33p is unique and has an apparent mass of 55 kDa. Disruption of A. fumigatus ECM33 results in a mutant with several morphogenetic aberrations, including the following: (i) a defect in conidial separation, (ii) an increase in the diameter of the conidia of the mutant associated with an increase in the concentration of the cell wall chitin, (iii) conidia that were sensitive to the absence of aeration during long-term storage, and (iv) conidia that were more resistant to killing by phagocytes, whereas the mycelium was more easily killed by neutrophils.
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Affiliation(s)
- Sandrine Chabane
- Aspergillus Unit, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
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203
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Theiss S, Ishdorj G, Brenot A, Kretschmar M, Lan CY, Nichterlein T, Hacker J, Nigam S, Agabian N, Köhler GA. Inactivation of the phospholipase B gene PLB5 in wild-type Candida albicans reduces cell-associated phospholipase A2 activity and attenuates virulence. Int J Med Microbiol 2006; 296:405-20. [PMID: 16759910 PMCID: PMC2481510 DOI: 10.1016/j.ijmm.2006.03.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 03/15/2006] [Accepted: 03/15/2006] [Indexed: 11/24/2022] Open
Abstract
Phospholipases are critical for modification and redistribution of lipid substrates, membrane remodeling and microbial virulence. Among the many different classes of phospholipases, fungal phospholipase B (Plb) proteins show the broadest range of substrate specificity and hydrolytic activity, hydrolyzing acyl ester bonds in phospholipids and lysophospholipids and further catalyzing lysophospholipase-transacylase reactions. The genome of the opportunistic fungal pathogen Candida albicans encodes a PLB multigene family with five putative members; we present the first characterization of this group of potential virulence determinants. CaPLB5, the third member of this multigene family characterized herein is a putative secretory protein with a predicted GPI-anchor attachment site. Real-time RT-PCR gene expression analysis of CaPLB5 and the additional CaPLB gene family members revealed that filamentous growth and physiologically relevant environmental conditions are associated with increased PLB gene activity. The phenotypes expressed by null mutant and revertant strains of CaPLB5 indicate that this lipid hydrolase plays an important role for cell-associated phospholipase A(2) activity and in vivo organ colonization.
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Affiliation(s)
- Stephanie Theiss
- Zentrum für Infektionsforschung, Universität Würzburg, Würzburg, Germany
- Institut für Hygiene und Mikrobiologie, Universität Würzburg, Würzburg, Germany
| | - Ganchimeg Ishdorj
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Universitäsklinikum Benjamin Franklin, Free University Berlin, Berlin, Germany
| | - Audrey Brenot
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | | | - Chung-Yu Lan
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Thomas Nichterlein
- Mikrobiologie und Hygiene, Klinikum der Stadt Mannheim, Mannheim, Germany
| | - Jörg Hacker
- Institut für Molekulare Infektionsbiologie, Universität Würzburg, Würzburg, Germany
| | - Santosh Nigam
- Eicosanoid Research Division and Center for Experimental Gynecology & Breast Research, Universitäsklinikum Benjamin Franklin, Free University Berlin, Berlin, Germany
| | - Nina Agabian
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Gerwald A. Köhler
- Zentrum für Infektionsforschung, Universität Würzburg, Würzburg, Germany
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Corresponding author: Gerwald A. Köhler, Ph.D., Department of Biochemistry & Microbiology, Oklahoma State University, Center for Health Sciences, 1111 West 17th Street, Tulsa, OK 74107-1898 U.S.A.. Phone: ++ 1 918 561 8302; Fax: ++ 1 918 561 5798; E-mail:
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204
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Ruiz-Herrera J, Elorza MV, Valentín E, Sentandreu R. Molecular organization of the cell wall of Candida albicans and its relation to pathogenicity. FEMS Yeast Res 2006; 6:14-29. [PMID: 16423067 DOI: 10.1111/j.1567-1364.2005.00017.x] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Candida albicans is one of the most important opportunistic pathogenic fungi. Weakening of the defense mechanisms of the host, and the ability of the microorganism to adapt to the environment prevailing in the host tissues, turn the fungus from a rather harmless saprophyte into an aggressive pathogen. The disease, candidiasis, ranges from light superficial infections to deep processes that endanger the life of the patient. In the establishment of the pathogenic process, the cell wall of C. albicans (as in other pathogenic fungi) plays an important role. It is the outer structure that protects the fungus from the host defense mechanisms and initiates the direct contact with the host cells by adhering to their surface. The wall also contains important antigens and other compounds that affect the homeostatic equilibrium of the host in favor of the parasite. In this review, we discuss our present knowledge of the structure of the cell wall of C. albicans, the synthesis of its different components, and the mechanisms involved in their organization to give rise to a coherent composite. Furthermore, special emphasis has been placed on two further aspects: how the composition and structure of C. albicans cell wall compare with those from other fungi, and establishing the role of some specific wall components in pathogenesis. From the data presented here, it becomes clear that the composition, structure and synthesis of the cell wall of C. albicans display both subtle and important differences with the wall of different saprophytic fungi, and that some of these differences are of utmost importance for its pathogenic behavior.
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Affiliation(s)
- José Ruiz-Herrera
- Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Mexico
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205
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Bowman SM, Piwowar A, Al Dabbous M, Vierula J, Free SJ. Mutational analysis of the glycosylphosphatidylinositol (GPI) anchor pathway demonstrates that GPI-anchored proteins are required for cell wall biogenesis and normal hyphal growth in Neurospora crassa. EUKARYOTIC CELL 2006; 5:587-600. [PMID: 16524913 PMCID: PMC1398062 DOI: 10.1128/ec.5.3.587-600.2006] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Using mutational and proteomic approaches, we have demonstrated the importance of the glycosylphosphatidylinositol (GPI) anchor pathway for cell wall synthesis and integrity and for the overall morphology of the filamentous fungus Neurospora crassa. Mutants affected in the gpig-1, gpip-1, gpip-2, gpip-3, and gpit-1 genes, which encode components of the N. crassa GPI anchor biosynthetic pathway, have been characterized. GPI anchor mutants exhibit colonial morphologies, significantly reduced rates of growth, altered hyphal growth patterns, considerable cellular lysis, and an abnormal "cell-within-a-cell" phenotype. The mutants are deficient in the production of GPI-anchored proteins, verifying the requirement of each altered gene for the process of GPI-anchoring. The mutant cell walls are abnormally weak, contain reduced amounts of protein, and have an altered carbohydrate composition. The mutant cell walls lack a number of GPI-anchored proteins, putatively involved in cell wall biogenesis and remodeling. From these studies, we conclude that the GPI anchor pathway is critical for proper cell wall structure and function in N. crassa.
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Affiliation(s)
- Shaun M Bowman
- Department of Biological Sciences, Cooke Hall, Room 109, The University at Buffalo, Buffalo, NY 14260, USA
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206
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Wang C, St. Leger RJ. A collagenous protective coat enables Metarhizium anisopliae to evade insect immune responses. Proc Natl Acad Sci U S A 2006; 103:6647-52. [PMID: 16614065 PMCID: PMC1458935 DOI: 10.1073/pnas.0601951103] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The ubiquitous fungal pathogen Metarhizium anisopliae kills a wide range of insects. Host hemocytes can recognize and ingest its conidia, but this capacity is lost on production of hyphal bodies. We show that the unusual ability of hyphal bodies to avoid detection depends on a gene (Mcl1) that is expressed within 20 min of the pathogen contacting hemolymph. A mutant disrupted in Mcl1 is rapidly attacked by hemocytes and shows a corresponding reduction of virulence to Manduca sexta. Mcl1 encodes a three domain protein comprising a hydrophilic, negatively charged N-terminal region with 14 cysteine residues, a central region comprising tandem repeats (GXY) characteristic of collagenous domains, and a C-terminal region that includes a glycosylphosphatidylinositol-dependent cell wall attachment site. Immunofluorescence assay showed that hyphal bodies are covered by the N-terminal domains of MCL1. The collagen domain became antibody accessible after treatment with DTT, suggesting that the N termini are linked by interchain disulfide bonds and are presented on the cell surface by extended collagenous fibers. Studies with staining reagents and hemocyte monolayers showed that MCL1 functions as an antiadhesive protective coat because it masks antigenic structural components of the cell wall such as beta-glucans, and because its hydrophilic negatively charged nature makes it unattractive to hemocytes. A survey of 54 fungal genomes revealed that seven other species have proteins with collagenous domains suggesting that MCL1 is a member of a patchily distributed gene family.
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Affiliation(s)
- Chengshu Wang
- Department of Entomology, University of Maryland, College Park, MD 20742
| | - Raymond J. St. Leger
- Department of Entomology, University of Maryland, College Park, MD 20742
- *To whom correspondence should be addressed. E-mail:
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207
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Brunke S, Hube B. MfLIP1, a gene encoding an extracellular lipase of the lipid-dependent fungus Malassezia furfur. Microbiology (Reading) 2006; 152:547-554. [PMID: 16436442 DOI: 10.1099/mic.0.28501-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Malassezia furfur is a dimorphic fungus and a member of the normal cutaneous microflora of humans. However, it is also a facultative pathogen, associated with a wide range of skin diseases. One unusual feature of M. furfur is an absolute dependency on externally provided lipids which the fungus hydrolyses by lipolytic activity to release fatty acids necessary for both growth and pathogenicity. In this study, the cloning and characterization of the first gene encoding a secreted lipase of M. furfur possibly associated with this activity are reported. The gene, MfLIP1, shows high sequence similarity to other known extracellular lipases, but is not a member of a lipase gene family in M. furfur. MfLIP1 consists of 1464 bp, encoding a protein with a molecular mass of 54·3 kDa, a conserved lipase motif and an N-terminal signal peptide of 26 aa. By using a genomic library, two other genes were identified flanking MfLIP1, one of them encoding a putative secreted catalase, the other a putative amine oxidase. The cDNA of MfLIP1 was expressed in Pichia pastoris and the biochemical properties of the recombinant lipase were analysed. MfLip1 is most active at 40 °C and the pH optimum was found to be 5·8. The lipase hydrolysed lipids, such as Tweens, frequently used as the source of fatty acids in M. furfur media, and had minor esterase activity. Furthermore, the lipase is inhibited by different bivalent metal ions. This is the first molecular description of a secreted lipase from M. furfur.
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Affiliation(s)
- Sascha Brunke
- Robert Koch-Institut, Nordufer 20, D-13353, Berlin, Germany
| | - Bernhard Hube
- Robert Koch-Institut, Nordufer 20, D-13353, Berlin, Germany
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208
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Albrecht A, Felk A, Pichova I, Naglik JR, Schaller M, de Groot P, Maccallum D, Odds FC, Schäfer W, Klis F, Monod M, Hube B. Glycosylphosphatidylinositol-anchored Proteases of Candida albicans Target Proteins Necessary for Both Cellular Processes and Host-Pathogen Interactions. J Biol Chem 2006; 281:688-94. [PMID: 16269404 DOI: 10.1074/jbc.m509297200] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Intracellular and secreted proteases fulfill multiple functions in microorganisms. In pathogenic microorganisms extracellular proteases may be adapted to interactions with host cells. Here we describe two cell surface-associated aspartic proteases, Sap9 and Sap10, which have structural similarities to yapsins of Saccharomyces cerevisiae and are produced by the human pathogenic yeast Candida albicans. Sap9 and Sap10 are glycosylphosphatidylinositol-anchored and located in the cell membrane or the cell wall. Both proteases are glycosylated, cleave at dibasic or basic processing sites similar to yapsins and Kex2-like proteases, and have functions in cell surface integrity and cell separation during budding. Overexpression of SAP9 in mutants lacking KEX2 or SAP10, or of SAP10 in mutants lacking KEX2 or SAP9, only partially restored these phenotypes, suggesting distinct target proteins of fungal origin for each of the three proteases. In addition, deletion of SAP9 and SAP10 modified the adhesion properties of C. albicans to epithelial cells and caused attenuated epithelial cell damage during experimental oral infection suggesting a unique role for these proteases in both cellular processes and host-pathogen interactions.
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209
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O'Toole N, Min XJ, Butler G, Storms R, Tsang A. Sequence-Based Analysis of Fungal Secretomes. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1874-5334(06)80015-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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210
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Phalip V, Delalande F, Carapito C, Goubet F, Hatsch D, Leize-Wagner E, Dupree P, Dorsselaer AV, Jeltsch JM. Diversity of the exoproteome of Fusarium graminearum grown on plant cell wall. Curr Genet 2005; 48:366-79. [PMID: 16283313 DOI: 10.1007/s00294-005-0040-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Revised: 10/25/2005] [Accepted: 10/25/2005] [Indexed: 11/30/2022]
Abstract
The exoproteome of the fungus Fusarium graminearum grown on glucose and on hop (Humulus lupulus, L.) cell wall has been investigated. The culture medium was found to contain a higher quantity of proteins and the proteins are more diverse when the fungus is grown on cell wall. Using both 1D and 2D electrophoresis followed by mass spectrometry analysis and protein identification based on similarity searches, 84 unique proteins were identified in the cell wall-grown fungal exoproteome. Many are putatively implicated in carbohydrate metabolism, mainly in cell wall polysaccharide degradation. The predicted carbohydrate-active enzymes fell into 24 different enzymes classes, and up to eight different proteins within a same class are secreted. This indicates that fungal metabolism becomes oriented towards synthesis and secretion of a whole arsenal of enzymes able to digest almost the complete plant cell wall. Cellobiohydrolase is one of the only four proteins found both after growth on glucose and on plant cell wall and we propose that this enzyme could act as a sensor of the extracellular environment. Extensive knowledge of this very diverse F. graminearum exoproteome is an important step towards the full understanding of Fusarium/plants interactions.
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Affiliation(s)
- Vincent Phalip
- UMR 7175-Laboratoire de Phytopathologie, Université Louis Pasteur, Illkirch, France.
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211
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Damveld RA, Arentshorst M, VanKuyk PA, Klis FM, van den Hondel CAMJJ, Ram AFJ. Characterisation of CwpA, a putative glycosylphosphatidylinositol-anchored cell wall mannoprotein in the filamentous fungus Aspergillus niger. Fungal Genet Biol 2005; 42:873-85. [PMID: 16154783 DOI: 10.1016/j.fgb.2005.06.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 06/22/2005] [Accepted: 06/22/2005] [Indexed: 11/28/2022]
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins in fungi are found at the cell surface, either as plasma membrane proteins (GPI-PMPs) or attached by a remnant of the GPI-anchor to the cell wall (GPI-CWPs). GPI-CWPs can be extracted from the cell wall by treatment with hydrofluoric acid (HF), which cleaves the phosphodiester bond that is present in the remnant of the GPI-anchor. The filamentous fungus Aspergillus niger contains at least seven HF-extractable cell wall mannoproteins. One gene encoding an HF-extractable cell wall mannoprotein, cwpA, was cloned and further characterised. The protein sequence of CwpA indicated the presence of two hydrophobic signal sequences both at the N-terminus and C-terminus of the protein, for entering the ER and the addition of a GPI-anchor, respectively. A CwpA-specific antiserum was raised and in combination with fractionation experiments, we show that this protein was abundantly present as an HF-extractable protein in the cell wall of A. niger.
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Affiliation(s)
- Robbert A Damveld
- Institute of Biology, Clusius Laboratory, Leiden University, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
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212
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De Groot PWJ, Ram AF, Klis FM. Features and functions of covalently linked proteins in fungal cell walls. Fungal Genet Biol 2005; 42:657-75. [PMID: 15896991 DOI: 10.1016/j.fgb.2005.04.002] [Citation(s) in RCA: 194] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 04/04/2005] [Accepted: 04/05/2005] [Indexed: 10/25/2022]
Abstract
The cell walls of many ascomycetous yeasts consist of an internal network of stress-bearing polysaccharides, which serve as a scaffold for a dense external layer of glycoproteins. GPI-modified proteins are the most abundant cell wall proteins and often display a common organization. Their C-terminus can link them covalently to the polysaccharide network, they possess an internal serine- and threonine-rich spacer domain, and the N-terminal region contains a functional domain. Other proteins bind to the polysaccharide network through a mild-alkali-sensitive linkage. Many cell wall proteins are carbohydrate/glycan-modifying enzymes; adhesion proteins are prominent; proteins involved in iron uptake are present, and also specialized proteins that probably help the fungus to survive in its natural environment. The protein composition of the cell wall depends on environmental conditions and developmental stage. We present evidence that the cell wall of mycelial species of the Ascomycotina is similarly organized and contains glycoproteins with comparable functions.
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Affiliation(s)
- Piet W J De Groot
- Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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213
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Braun BR, van het Hoog M, d'Enfert C, Martchenko M, Dungan J, Kuo A, Inglis DO, Uhl MA, Hogues H, Berriman M, Lorenz M, Levitin A, Oberholzer U, Bachewich C, Harcus D, Marcil A, Dignard D, Iouk T, Zito R, Frangeul L, Tekaia F, Rutherford K, Wang E, Munro CA, Bates S, Gow NA, Hoyer LL, Köhler G, Morschhäuser J, Newport G, Znaidi S, Raymond M, Turcotte B, Sherlock G, Costanzo M, Ihmels J, Berman J, Sanglard D, Agabian N, Mitchell AP, Johnson AD, Whiteway M, Nantel A. A human-curated annotation of the Candida albicans genome. PLoS Genet 2005; 1:36-57. [PMID: 16103911 PMCID: PMC1183520 DOI: 10.1371/journal.pgen.0010001] [Citation(s) in RCA: 252] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2005] [Accepted: 03/14/2005] [Indexed: 11/24/2022] Open
Abstract
Recent sequencing and assembly of the genome for the fungal pathogen Candida albicans used simple automated procedures for the identification of putative genes. We have reviewed the entire assembly, both by hand and with additional bioinformatic resources, to accurately map and describe 6,354 genes and to identify 246 genes whose original database entries contained sequencing errors (or possibly mutations) that affect their reading frame. Comparison with other fungal genomes permitted the identification of numerous fungus-specific genes that might be targeted for antifungal therapy. We also observed that, compared to other fungi, the protein-coding sequences in the C. albicans genome are especially rich in short sequence repeats. Finally, our improved annotation permitted a detailed analysis of several multigene families, and comparative genomic studies showed that C. albicans has a far greater catabolic range, encoding respiratory Complex 1, several novel oxidoreductases and ketone body degrading enzymes, malonyl-CoA and enoyl-CoA carriers, several novel amino acid degrading enzymes, a variety of secreted catabolic lipases and proteases, and numerous transporters to assimilate the resulting nutrients. The results of these efforts will ensure that the Candida research community has uniform and comprehensive genomic information for medical research as well as for future diagnostic and therapeutic applications.
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Affiliation(s)
- Burkhard R Braun
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Marco van het Hoog
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Christophe d'Enfert
- Unité Postulante Biologie et Pathogénicité Fongiques, INRA USC 2019, Institut Pasteur, Paris, France
| | - Mikhail Martchenko
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Jan Dungan
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Alan Kuo
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Diane O Inglis
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - M. Andrew Uhl
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Hervé Hogues
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | | | - Michael Lorenz
- Department of Microbiology and Molecular Genetics, Utah-Houston Medical School, Houston, Texas, United States of America
| | - Anastasia Levitin
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Ursula Oberholzer
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Catherine Bachewich
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Doreen Harcus
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Anne Marcil
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Daniel Dignard
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Tatiana Iouk
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Rosa Zito
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Lionel Frangeul
- Plate-Forme Intégration et Analyse Génomique, Institut Pasteur, Paris, France
| | - Fredj Tekaia
- Unité de Génétique Moléculaire des Levures, Institut Pasteur, Paris, France
| | | | - Edwin Wang
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - Carol A Munro
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Steve Bates
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Neil A Gow
- School of Medical Sciences, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Lois L Hoyer
- Department of Veterinary Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Gerwald Köhler
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Joachim Morschhäuser
- Institut für Molekulare Infektionsbiologie, Universität Wurzburg, Wurzburg, Germany
| | - George Newport
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Sadri Znaidi
- Institut de Recherches Cliniques de Montreal, Montreal, Quebec, Canada
| | - Martine Raymond
- Institut de Recherches Cliniques de Montreal, Montreal, Quebec, Canada
| | - Bernard Turcotte
- Department of Medicine, Royal Victoria Hospital, McGill University, Montreal, Quebec, Canada
| | - Gavin Sherlock
- Department of Genetics, Stanford University School of Medicine, Palo Alto, California, United States of America
| | - Maria Costanzo
- Department of Genetics, Stanford University School of Medicine, Palo Alto, California, United States of America
| | - Jan Ihmels
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Judith Berman
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Dominique Sanglard
- Institute of Microbiology, University Hospital Lausanne, Lausanne, Switzerland
| | - Nina Agabian
- Department of Stomatology, University of California, San Francisco, California, United States of America
| | - Aaron P Mitchell
- Department of Microbiology and Institute of Cancer Research, Columbia University, New York, New York, United States of America
| | - Alexander D Johnson
- Department of Microbiology and Immunology, University of California, San Francisco, California, United States of America
| | - Malcolm Whiteway
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
| | - André Nantel
- Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, Canada
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214
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Werten MWT, de Wolf FA. Reduced proteolysis of secreted gelatin and Yps1-mediated alpha-factor leader processing in a Pichia pastoris kex2 disruptant. Appl Environ Microbiol 2005; 71:2310-7. [PMID: 15870316 PMCID: PMC1087524 DOI: 10.1128/aem.71.5.2310-2317.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heterologous proteins secreted by yeast and fungal expression hosts are occasionally degraded at basic amino acids. We cloned Pichia pastoris homologs of the Saccharomyces cerevisiae basic residue-specific endoproteases Kex2 and Yps1 to evaluate their involvement in the degradation of a secreted mammalian gelatin. Disruption of the P. pastoris KEX2 gene prevented proteolysis of the foreign protein at specific monoarginylic sites. The S. cerevisiae alpha-factor preproleader used to direct high-level gelatin secretion was correctly processed at its dibasic site in the absence of the prototypical proprotein convertase Kex2. Disruption of the YPS1 gene had no effect on gelatin degradation or processing of the alpha-factor propeptide. When both the KEX2 and YPS1 genes were disrupted, correct precursor maturation no longer occurred. The different substrate specificities of both proteases and their mutual redundancy for propeptide processing indicate that P. pastoris kex2 and yps1 single-gene disruptants can be used for the alpha-factor leader-directed secretion of heterologous proteins otherwise degraded at basic residues.
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Affiliation(s)
- Marc W T Werten
- Agrotechnology & Food Innovations B.V., Wageningen UR, Bornsesteeg 59, NL-6708 PD Wageningen, The Netherlands.
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215
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Latgé JP, Mouyna I, Tekaia F, Beauvais A, Debeaupuis JP, Nierman W. Specific molecular features in the organization and biosynthesis of the cell wall ofAspergillus fumigatus. Med Mycol 2005; 43 Suppl 1:S15-22. [PMID: 16110787 DOI: 10.1080/13693780400029155] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The cell wall of Aspergillus fumigatus is composed of a branched beta1,3 glucan covalently bound to chitin, beta1,3, beta1,4 glucans, and galactomannan, that is embedded in an amorphous cement composed of alpha1,3 glucan, galactomannan and polygalactosamin. The mycelial cell wall of A. fumigatus is very different from the yeast Saccharomyces cerevisiae cell wall, and in particular lacks beta1,6 glucans and proteins covalently bound to cell wall polysaccharides. The differences in cell wall composition between the mould A. fumigatus and the yeast S. cerevisiae are also reflected at the genomic level where unique features have been identified in A. fumigatus. A single gene codes for the glucan synthase catalytic subumit; this finding has lead to the development of a RNAi methodology for the disruption of essential genes in A. fumigatus. In contrast to the glucan synthase, multiple genes have been found in the chitin synthase and the alpha glucan synthase families; in spite of homologous sequences, each gene in each family have very different function. Similarly homologous mannosyltransferase genes are found in yeast and moulds but they lead to the synthesis of very different N-mannan structures. This chemo-genomic comparative analysis has also suggested that GPI-anchored proteins do not have a role of linker in the three dimensional organization of the fungal cell wall.
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Affiliation(s)
- J P Latgé
- Unité des Aspergillus, Institut Pasteur, Paris, France.
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216
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Ten Have A, Dekkers E, Kay J, Phylip LH, van Kan JAL. An aspartic proteinase gene family in the filamentous fungus Botrytis cinerea contains members with novel features. MICROBIOLOGY-SGM 2004; 150:2475-2489. [PMID: 15256589 DOI: 10.1099/mic.0.27058-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Botrytis cinerea, an important fungal plant pathogen, secretes aspartic proteinase (AP) activity in axenic cultures. No cysteine, serine or metalloproteinase activity could be detected. Proteinase activity was higher in culture medium containing BSA or wheat germ extract, as compared to minimal medium. A proportion of the enzyme activity remained in the extracellular glucan sheath. AP was also the only type of proteinase activity in fluid obtained from B. cinerea-infected tissue of apple, pepper, tomato and zucchini. Five B. cinerea genes encoding an AP were cloned and denoted Bcap1-5. Features of the encoded proteins are discussed. BcAP1, especially, has novel characteristics. A phylogenetic analysis was performed comprising sequences originating from different kingdoms. BcAP1 and BcAP5 did not cluster in a bootstrap-supported clade. BcAP2 clusters with vacuolar APs. BcAP3 and BcAP4 cluster with secreted APs in a clade that also contains glycosylphosphatidylinositol-anchored proteinases from Saccharomyces cerevisiae and Candida albicans. All five Bcap genes are expressed in liquid cultures. Transcript levels of Bcap1, Bcap2, Bcap3 and Bcap4 are subject to glucose and peptone repression. Transcripts from all five Bcap genes were detected in infected plant tissue, indicating that at least part of the AP activity in planta originates from the pathogen.
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Affiliation(s)
- Arjen Ten Have
- Laboratory of Phytopathology, Wageningen University, Binnenhaven 5, PO Box 8025, 6700 EE Wageningen, The Netherlands
| | - Ester Dekkers
- Laboratory of Phytopathology, Wageningen University, Binnenhaven 5, PO Box 8025, 6700 EE Wageningen, The Netherlands
| | - John Kay
- Cardiff School of Biosciences, Cardiff University, PO Box 911, Cardiff CF10 3US, UK
| | - Lowri H Phylip
- Cardiff School of Biosciences, Cardiff University, PO Box 911, Cardiff CF10 3US, UK
| | - Jan A L van Kan
- Laboratory of Phytopathology, Wageningen University, Binnenhaven 5, PO Box 8025, 6700 EE Wageningen, The Netherlands
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