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Yang C, Guo X, Shan Y, He Z, Jiang D, Wang X, Wang L. The expression profile of calnexin in Patinopecten yessoensis after acute high temperature stress. FISH AND SHELLFISH IMMUNOLOGY REPORTS 2021; 2:100016. [DOI: 10.1016/j.fsirep.2021.100016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/23/2021] [Accepted: 07/01/2021] [Indexed: 11/29/2022] Open
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2
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Gabriel R, Mueller R, Floerl L, Hopson C, Harth S, Schuerg T, Fleissner A, Singer SW. CAZymes from the thermophilic fungus Thermoascus aurantiacus are induced by C5 and C6 sugars. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:169. [PMID: 34384463 PMCID: PMC8359064 DOI: 10.1186/s13068-021-02018-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Filamentous fungi are excellent lignocellulose degraders, which they achieve through producing carbohydrate active enzymes (CAZymes). CAZyme production is highly orchestrated and gene expression analysis has greatly expanded understanding of this important biotechnological process. The thermophilic fungus Thermoascus aurantiacus secretes highly active thermostable enzymes that enable saccharifications at higher temperatures; however, the genome-wide measurements of gene expression in response to CAZyme induction are not understood. RESULTS A fed-batch system with plant biomass-derived sugars D-xylose, L-arabinose and cellobiose established that these sugars induce CAZyme expression in T. aurantiacus. The C5 sugars induced both cellulases and hemicellulases, while cellobiose specifically induced cellulases. A minimal medium formulation was developed to enable gene expression studies of T. aurantiacus with these inducers. It was found that d-xylose and L-arabinose strongly induced a wide variety of CAZymes, auxiliary activity (AA) enzymes and carbohydrate esterases (CEs), while cellobiose facilitated lower expression of mostly cellulase genes. Furthermore, putative orthologues of different unfolded protein response genes were up-regulated during the C5 sugar feeding together with genes in the C5 sugar assimilation pathways. CONCLUSION This work has identified two additional CAZyme inducers for T. aurantiacus, L-arabinose and cellobiose, along with D-xylose. A combination of biochemical assays and RNA-seq measurements established that C5 sugars induce a suite of cellulases and hemicellulases, providing paths to produce broad spectrum thermotolerant enzymatic mixtures.
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Affiliation(s)
- Raphael Gabriel
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Institut Für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Rebecca Mueller
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Institut Für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
| | - Lena Floerl
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna (BOKU), Muthgasse 18, 1190, Vienna, Austria
- Laboratory of Food Systems Biotechnology, Institute of Food, Nutrition and Health, ETH Zurich, Zurich, Switzerland
| | - Cynthia Hopson
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Department of Chemical Engineering and Materials, Faculty of Chemistry, Complutense University of Madrid, Av. Complutense s/n, 28040, Madrid, Spain
| | - Simon Harth
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
- Frankfurt Institute of Molecular Biosciences, Goethe University Frankfurt, 60438, Frankfurt am Main, Germany
| | - Timo Schuerg
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA
| | - Andre Fleissner
- Institut Für Genetik, Technische Universität Braunschweig, Spielmannstr. 7, 38106, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Rebenring 56, 38106, Braunschweig, Germany
| | - Steven W Singer
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 9720, USA.
- Joint BioEnergy Institute, Emeryville, CA, 94608, USA.
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3
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Jin FJ, Hu S, Wang BT, Jin L. Advances in Genetic Engineering Technology and Its Application in the Industrial Fungus Aspergillus oryzae. Front Microbiol 2021; 12:644404. [PMID: 33708187 PMCID: PMC7940364 DOI: 10.3389/fmicb.2021.644404] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/05/2021] [Indexed: 12/19/2022] Open
Abstract
The filamentous fungus Aspergillus oryzae is an important strain in the traditional fermentation and food processing industries and is often used in the production of soy sauce, soybean paste, and liquor-making. In addition, A. oryzae has a strong capacity to secrete large amounts of hydrolytic enzymes; therefore, it has also been used in the enzyme industry as a cell factory for the production of numerous native and heterologous enzymes. However, the production and secretion of foreign proteins by A. oryzae are often limited by numerous bottlenecks that occur during transcription, translation, protein folding, translocation, degradation, transport, secretion, etc. The existence of these problems makes it difficult to achieve the desired target in the production of foreign proteins by A. oryzae. In recent years, with the decipherment of the whole genome sequence, basic research and genetic engineering technologies related to the production and utilization of A. oryzae have been well developed, such as the improvement of homologous recombination efficiency, application of selectable marker genes, development of large chromosome deletion technology, utilization of hyphal fusion techniques, and application of CRISPR/Cas9 genome editing systems. The development and establishment of these genetic engineering technologies provided a great deal of technical support for the industrial production and application of A. oryzae. This paper reviews the advances in basic research and genetic engineering technologies of the fermentation strain A. oryzae mentioned above to open up more effective ways and research space for the breeding of A. oryzae production strains in the future.
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Affiliation(s)
- Feng-Jie Jin
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Shuang Hu
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Bao-Teng Wang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
| | - Long Jin
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing, China
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4
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Boppidi KR, Ribeiro LFC, Iambamrung S, Nelson SM, Wang Y, Momany M, Richardson EA, Lincoln S, Srivastava R, Harris SD, Marten MR. Altered secretion patterns and cell wall organization caused by loss of PodB function in the filamentous fungus Aspergillus nidulans. Sci Rep 2018; 8:11433. [PMID: 30061727 PMCID: PMC6065416 DOI: 10.1038/s41598-018-29615-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 07/12/2018] [Indexed: 12/27/2022] Open
Abstract
Filamentous fungi are widely used in the production of a variety of industrially relevant enzymes and proteins as they have the unique ability to secrete tremendous amounts of proteins. However, the secretory pathways in filamentous fungi are not completely understood. Here, we investigated the role of a mutation in the POlarity Defective (podB) gene on growth, protein secretion, and cell wall organization in Aspergillus nidulans using a temperature sensitive (Ts) mutant. At restrictive temperature, the mutation resulted in lack of biomass accumulation, but led to a significant increase in specific protein productivity. Proteomic analysis of the secretome showed that the relative abundance of 584 (out of 747 identified) proteins was altered due to the mutation. Of these, 517 were secreted at higher levels. Other phenotypic differences observed in the mutant include up-regulation of unfolded protein response (UPR), deformation of Golgi apparatus and uneven cell wall thickness. Furthermore, proteomic analysis of cell wall components in the mutant revealed the presence of intracellular proteins in higher abundance accompanied by lower levels of most cell wall proteins. Taken together, results from this study suggest the importance of PodB as a target when engineering fungal strains for enhanced secretion of valuable biomolecules.
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Affiliation(s)
- Karthik R Boppidi
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Liliane Fraga Costa Ribeiro
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Sirasa Iambamrung
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Sidney M Nelson
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA
| | - Yan Wang
- University of Maryland - College Park, Department of Cell Biology and Molecular Genetics, College Park, MD, USA
| | - Michelle Momany
- University of Georgia, Fungal Biology Group and Department of Plant Biology, Athens, GA, USA
| | | | - Stephen Lincoln
- University of Connecticut, Department of Chemical and Biomolecular Engineering, Storrs, CT, USA
| | - Ranjan Srivastava
- University of Connecticut, Department of Chemical and Biomolecular Engineering, Storrs, CT, USA
| | - Steven D Harris
- University of Manitoba, Department of Biological Sciences, Winnipeg, MB, Canada
| | - Mark R Marten
- University of Maryland - Baltimore County, Department of Chemical Biochemical and Environmental Engineering, Baltimore, MD, USA.
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5
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Functional and transcriptomic analysis of the key unfolded protein response transcription factor HacA in Aspergillus oryzae. Gene 2016; 593:143-153. [DOI: 10.1016/j.gene.2016.08.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 08/04/2016] [Accepted: 08/08/2016] [Indexed: 12/31/2022]
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6
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Heimel K. Unfolded protein response in filamentous fungi-implications in biotechnology. Appl Microbiol Biotechnol 2014; 99:121-32. [PMID: 25384707 DOI: 10.1007/s00253-014-6192-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/24/2014] [Accepted: 10/27/2014] [Indexed: 01/16/2023]
Abstract
The unfolded protein response (UPR) represents a mechanism to preserve endoplasmic reticulum (ER) homeostasis that is conserved in eukaryotes. ER stress caused by the accumulation of potentially toxic un- or misfolded proteins in the ER triggers UPR activation and the induction of genes important for protein folding in the ER, ER expansion, and transport from and to the ER. Along with this adaptation, the overall capacity for protein secretion is markedly increased by the UPR. In filamentous fungi, various approaches to employ the UPR for improved production of homologous and heterologous proteins have been investigated. As the effects on protein production were strongly dependent on the expressed protein, generally applicable strategies have to be developed. A combination of transcriptomic approaches monitoring secretion stress and basic research on the UPR mechanism provided novel and important insight into the complex regulatory cross-connections between UPR signalling, cellular physiology, and developmental processes. It will be discussed how this increasing knowledge on the UPR might stimulate the development of novel strategies for using the UPR as a tool in biotechnology.
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Affiliation(s)
- Kai Heimel
- Institut für Mikrobiologie & Genetik, Georg-August-Universität, Grisebachstr. 8, 37077, Göttingen, Germany,
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7
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Kwon MJ, Jørgensen TR, Nitsche BM, Arentshorst M, Park J, Ram AFJ, Meyer V. The transcriptomic fingerprint of glucoamylase over-expression in Aspergillus niger. BMC Genomics 2012; 13:701. [PMID: 23237452 PMCID: PMC3554566 DOI: 10.1186/1471-2164-13-701] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 12/06/2012] [Indexed: 12/11/2022] Open
Abstract
Background Filamentous fungi such as Aspergillus niger are well known for their exceptionally high capacity for secretion of proteins, organic acids, and secondary metabolites and they are therefore used in biotechnology as versatile microbial production platforms. However, system-wide insights into their metabolic and secretory capacities are sparse and rational strain improvement approaches are therefore limited. In order to gain a genome-wide view on the transcriptional regulation of the protein secretory pathway of A. niger, we investigated the transcriptome of A. niger when it was forced to overexpression the glaA gene (encoding glucoamylase, GlaA) and secrete GlaA to high level. Results An A. niger wild-type strain and a GlaA over-expressing strain, containing multiple copies of the glaA gene, were cultivated under maltose-limited chemostat conditions (specific growth rate 0.1 h-1). Elevated glaA mRNA and extracellular GlaA levels in the over-expressing strain were accompanied by elevated transcript levels from 772 genes and lowered transcript levels from 815 genes when compared to the wild-type strain. Using GO term enrichment analysis, four higher-order categories were identified in the up-regulated gene set: i) endoplasmic reticulum (ER) membrane translocation, ii) protein glycosylation, iii) vesicle transport, and iv) ion homeostasis. Among these, about 130 genes had predicted functions for the passage of proteins through the ER and those genes included target genes of the HacA transcription factor that mediates the unfolded protein response (UPR), e.g. bipA, clxA, prpA, tigA and pdiA. In order to identify those genes that are important for high-level secretion of proteins by A. niger, we compared the transcriptome of the GlaA overexpression strain of A. niger with six other relevant transcriptomes of A. niger. Overall, 40 genes were found to have either elevated (from 36 genes) or lowered (from 4 genes) transcript levels under all conditions that were examined, thus defining the core set of genes important for ensuring high protein traffic through the secretory pathway. Conclusion We have defined the A. niger genes that respond to elevated secretion of GlaA and, furthermore, we have defined a core set of genes that appear to be involved more generally in the intensified traffic of proteins through the secretory pathway of A. niger. The consistent up-regulation of a gene encoding the acetyl-coenzyme A transporter suggests a possible role for transient acetylation to ensure correct folding of secreted proteins.
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Affiliation(s)
- Min Jin Kwon
- Department Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
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8
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Powers-Fletcher MV, Jambunathan K, Brewer JL, Krishnan K, Feng X, Galande AK, Askew DS. Impact of the lectin chaperone calnexin on the stress response, virulence and proteolytic secretome of the fungal pathogen Aspergillus fumigatus. PLoS One 2011; 6:e28865. [PMID: 22163332 PMCID: PMC3233604 DOI: 10.1371/journal.pone.0028865] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 11/16/2011] [Indexed: 11/18/2022] Open
Abstract
Calnexin is a membrane-bound lectin chaperone in the endoplasmic reticulum (ER) that is part of a quality control system that promotes the accurate folding of glycoproteins entering the secretory pathway. We have previously shown that ER homeostasis is important for virulence of the human fungal pathogen Aspergillus fumigatus, but the contribution of calnexin has not been explored. Here, we determined the extent to which A. fumigatus relies on calnexin for growth under conditions of environmental stress and for virulence. The calnexin gene, clxA, was deleted from A. fumigatus and complemented by reconstitution with the wild type gene. Loss of clxA altered the proteolytic secretome of the fungus, but had no impact on growth rates in either minimal or complex media at 37°C. However, the ΔclxA mutant was growth impaired at temperatures above 42°C and was hypersensitive to acute ER stress caused by the reducing agent dithiothreitol. In contrast to wild type A. fumigatus, ΔclxA hyphae were unable to grow when transferred to starvation medium. In addition, depleting the medium of cations by chelation prevented ΔclxA from sustaining polarized hyphal growth, resulting in blunted hyphae with irregular morphology. Despite these abnormal stress responses, the ΔclxA mutant remained virulent in two immunologically distinct models of invasive aspergillosis. These findings demonstrate that calnexin functions are needed for growth under conditions of thermal, ER and nutrient stress, but are dispensable for surviving the stresses encountered in the host environment.
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Affiliation(s)
- Margaret V. Powers-Fletcher
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | | | - Jordan L. Brewer
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Karthik Krishnan
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Xizhi Feng
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Amit K. Galande
- SRI International, Harrisonburg, Virginia, United States of America
| | - David S. Askew
- Department of Pathology & Laboratory Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
- * E-mail:
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9
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Ohno A, Maruyama JI, Nemoto T, Arioka M, Kitamoto K. A carrier fusion significantly induces unfolded protein response in heterologous protein production by Aspergillus oryzae. Appl Microbiol Biotechnol 2011; 92:1197-206. [PMID: 21822643 DOI: 10.1007/s00253-011-3487-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 07/14/2011] [Indexed: 11/26/2022]
Abstract
In heterologous protein production by filamentous fungi, target proteins are expressed as fusions with homologous secretory proteins, called carriers, for higher production yields. Although carrier fusion is thought to overcome the bottleneck in transcriptional and (post)translational processes during heterologous protein production, there is limited knowledge of its physiological effects on the host strain. In this study, we performed DNA microarray analysis by comparing gene expression patterns of two Aspergillus oryzae strains expressing either carrier- or non-carrier-fused bovine chymosin (CHY). When CHY was expressed as a fusion with α-amylase (AmyB), the production level increased by approximately 2-fold as compared with the non-carrier-fused CHY. DNA microarray analysis revealed that the carrier fusion significantly up-regulated many genes involved in endoplasmic reticulum (ER) protein-folding and secretion. Consistently, hacA transcripts were efficiently spliced in the strain expressing the carrier-fused CHY, indicating an unfolded protein response (UPR). The carrier-fused CHY was detected intracellularly without processing at the Kex2 cleavage site, which is likely recognized in the Golgi, and the carrier fusion delayed extracellular CHY production in the early growth phase as compared with the non-carrier-fused expression. Taken together, our data suggest a proposal that the carrier fusion temporarily accumulates the carrier-fused CHY in the ER and significantly induces UPR.
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Affiliation(s)
- Ayako Ohno
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Japan
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10
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Approaches for refining heterologous protein production in filamentous fungi. World J Microbiol Biotechnol 2009. [DOI: 10.1007/s11274-009-0128-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Genomic analysis of the secretion stress response in the enzyme-producing cell factory Aspergillus niger. BMC Genomics 2007; 8:158. [PMID: 17561995 PMCID: PMC1894978 DOI: 10.1186/1471-2164-8-158] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 06/11/2007] [Indexed: 11/29/2022] Open
Abstract
Background Filamentous fungi such as Aspergillus niger have a high capacity secretory system and are therefore widely exploited for the industrial production of native and heterologous proteins. However, in most cases the yields of non-fungal proteins are significantly lower than those obtained for fungal proteins. One well-studied bottleneck appears to be the result of mis-folding of heterologous proteins in the ER during early stages of secretion, with related stress responses in the host, including the unfolded protein response (UPR). This study aims at uncovering transcriptional and translational responses occurring in A. niger exposed to secretion stress. Results A genome-wide transcriptional analysis of protein secretion-related stress responses was determined using Affymetrix DNA GeneChips and independent verification for selected genes. Endoplasmic reticulum (ER)-associated stress was induced either by chemical treatment of the wild-type cells with dithiothreitol (DTT) or tunicamycin, or by expressing a human protein, tissue plasminogen activator (t-PA). All of these treatments triggered the UPR, as shown by the expression levels of several well-known UPR target genes. The predicted proteins encoded by most of the up-regulated genes function as part of the secretory system including chaperones, foldases, glycosylation enzymes, vesicle transport proteins, and ER-associated degradation proteins. Several genes were down-regulated under stress conditions and these included several genes that encode secreted enzymes. Moreover, translational regulation under ER stress was investigated by polysomal fractionation. This analysis confirmed the post-transcriptional control of hacA expression and highlighted that differential translation also occurs during ER stress, in particular for some genes encoding secreted proteins or proteins involved in ribosomal biogenesis and assembly. Conclusion This is first genome-wide analysis of both transcriptional and translational events following protein secretion stress. Insight has been gained into the molecular basis of protein secretion and secretion-related stress in an effective protein-secreting fungus, and provides an opportunity to identify target genes for manipulation in strain improvement strategies.
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12
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dos Santos Feitosa L, de Almeida Soares CM, Dos Santos MRM, Bailão AM, Xander P, Mortara RA, Lopes JD. Cloning, characterization and expression of a calnexin homologue from the pathogenic fungusParacoccidioides brasiliensis. Yeast 2007; 24:79-87. [PMID: 17173330 DOI: 10.1002/yea.1438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
We report the cloning of a Paracoccidioides brasiliensis cDNA, here named PbCnx, encoding the homologue of the endoplasmic reticulum molecular chaperone calnexin. Calnexin specifically recognizes monoglucosylated glycoproteins in the endoplasmic reticulum, thus being an essential component of the complex that interacts with the folded state of nascent secreted glycoproteins. The PbCnx open reading frame was found in a 1701 base pair (bp) fragment that encodes a 567 amino acid protein with an estimated mass of 62 680 Da. Northern and Southern blot hybridizations showed that PbCnx is encoded by a single, or a low number of, gene copies. PbCnx contains the hallmark KPEDWD motifs that are found in all members of the calnexin/calreticulin family proteins. A cDNA-encoding PbCnx was overexpressed as recombinant protein in Escherichia coli. The purified recombinant PbCnx was recognized by 6 out of 10 sera from PCM patients, a result that rules out its possible consideration for further use in diagnosis. Using confocal microscopy with anti-PbCnx mouse serum against yeast forms, a cytoplasmic staining pattern was observed.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Blotting, Western
- Calnexin/biosynthesis
- Calnexin/genetics
- Calnexin/immunology
- Cloning, Molecular
- DNA, Complementary/genetics
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- Epitopes/immunology
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Humans
- Mice
- Mice, Inbred BALB C
- Microscopy, Confocal
- Molecular Sequence Data
- Paracoccidioides/genetics
- Paracoccidioides/metabolism
- Paracoccidioidomycosis/blood
- Paracoccidioidomycosis/immunology
- RNA, Fungal/chemistry
- RNA, Fungal/genetics
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Sequence Homology
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Affiliation(s)
- Luciano dos Santos Feitosa
- Departamento de Microbiologia, Imunologia e Parasitologia da Universidade Federal de São Paulo, UNIFESP, São Paulo, Brazil
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13
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MacKenzie DA, Guillemette T, Al-Sheikh H, Watson AJ, Jeenes DJ, Wongwathanarat P, Dunn-Coleman NS, van Peij N, Archer DB. UPR-independent dithiothreitol stress-induced genes in Aspergillus niger. Mol Genet Genomics 2005; 274:410-8. [PMID: 16160852 DOI: 10.1007/s00438-005-0034-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Accepted: 07/08/2005] [Indexed: 10/25/2022]
Abstract
A subtraction library was prepared from cultures of Aspergillus niger that had or had not been exposed to dithiothreitol (DTT), in order to identify genes involved in the unfolded protein response (UPR) or in the response to reductive stress. A large fraction of the clones in the library (40%) encoded two putative methyltransferases (MTs) whose function has yet to be determined. Other stress-responsive genes included a homologue of the Mn2+-containing superoxide dismutase gene (sodB) and a number of genes predicted to code for products that function in protein turnover and in intra- and extracellular transport of molecules. Transcriptional microarray analysis was carried out with a group of 15 genes, comprising 11 from the cDNA library, two genes linked to the putative MT genes but not represented in the library, and two UPR control genes (bipA and pdiA). Eleven of the 15 genes were inducible with DTT. This was either reflected by the presence of transcripts in cells subjected to DTT stress compared to absence under control conditions, or by an induction ratio of between 1.4 and 8.0 in cases where transcripts were already detectable under control conditions. The MT genes were among the four most highly induced. None of the genes, apart from bipA and pdiA, showed significant induction in response to other stresses that are known to induce the UPR in fungi. We conclude that DTT alone does not provide for specific induction of UPR genes and that other stress conditions must also be examined.
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Affiliation(s)
- D A MacKenzie
- Department of Food Safety Science, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, UK.
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14
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Nevalainen KMH, Te'o VSJ, Bergquist PL. Heterologous protein expression in filamentous fungi. Trends Biotechnol 2005; 23:468-74. [PMID: 15967521 DOI: 10.1016/j.tibtech.2005.06.002] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 05/06/2005] [Accepted: 06/07/2005] [Indexed: 10/25/2022]
Abstract
Filamentous fungi are commonly used in the fermentation industry for the large-scale production of proteins--mainly industrial enzymes. Recent advances in fungal genomics and related experimental technologies such as gene arrays and proteomics are rapidly changing the approaches to the development and use of filamentous fungi as hosts for the production of both homologous and heterologous gene products. The emphasis is moving towards sourcing new genes of interest through database mining and unravelling the circuits related to fungal gene regulation, applying, for example, transcriptomics. However, although heterologous fungal proteins are efficiently expressed, expression of gene products from other organisms is subject to several bottlenecks that reduce yield. Current approaches emphasize the study of pathways involved in protein modification and degradation in general rather than gene-by-gene approaches.
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Affiliation(s)
- K M Helena Nevalainen
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney NSW 2109, Australia.
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Geysens S, Pakula T, Uusitalo J, Dewerte I, Penttilä M, Contreras R. Cloning and characterization of the glucosidase II alpha subunit gene of Trichoderma reesei: a frameshift mutation results in the aberrant glycosylation profile of the hypercellulolytic strain Rut-C30. Appl Environ Microbiol 2005; 71:2910-24. [PMID: 15932985 PMCID: PMC1151825 DOI: 10.1128/aem.71.6.2910-2924.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We describe isolation and characterization of the gene encoding the glucosidase II alpha subunit (GIIalpha) of the industrially important fungus Trichoderma reesei. This subunit is the catalytic part of the glucosidase II heterodimeric enzyme involved in the structural modification within the endoplasmic reticulum (ER) of N-linked oligosaccharides present on glycoproteins. The gene encoding GIIalpha (gls2alpha) in the hypercellulolytic strain Rut-C30 contains a frameshift mutation resulting in a truncated gene product. Based on the peculiar monoglucosylated N-glycan pattern on proteins produced by the strain, we concluded that the truncated protein can still hydrolyze the first alpha-1,3-linked glucose residue but not the innermost alpha-1,3-linked glucose residue from the Glc2Man9GlcNAc2 N-glycan ER structure. Transformation of the Rut-C30 strain with a repaired T. reesei gls2alpha gene changed the glycosylation profile significantly, decreasing the amount of monoglucosylated structures and increasing the amount of high-mannose N-glycans. Full conversion to high-mannose carbohydrates was not obtained, and this was probably due to competition between the endogenous mutant subunit and the introduced wild-type GIIalpha protein. Since glucosidase II is also involved in the ER quality control of nascent polypeptide chains, its transcriptional regulation was studied in a strain producing recombinant tissue plasminogen activator (tPA) and in cultures treated with the stress agents dithiothreitol (DTT) and brefeldin A (BFA), which are known to block protein transport and to induce the unfolded protein response. While the mRNA levels were clearly upregulated upon tPA production or BFA treatment, no such enhancement was observed after DTT addition.
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Affiliation(s)
- Steven Geysens
- Fundamental and Applied Molecular Biology, Department for Molecular Biomedical Research, Ghent University and VIB (Flemish Interuniversity Institute for Biotechnology), Ghent-Zwijnaarde, Belgium
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Sims AH, Gent ME, Lanthaler K, Dunn-Coleman NS, Oliver SG, Robson GD. Transcriptome analysis of recombinant protein secretion by Aspergillus nidulans and the unfolded-protein response in vivo. Appl Environ Microbiol 2005; 71:2737-47. [PMID: 15870366 PMCID: PMC1087583 DOI: 10.1128/aem.71.5.2737-2747.2005] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Filamentous fungi have a high capacity for producing large amounts of secreted proteins, a property that has been exploited for commercial production of recombinant proteins. However, the secretory pathway, which is key to the production of extracellular proteins, is rather poorly characterized in filamentous fungi compared to yeast. We report the effects of recombinant protein secretion on gene expression levels in Aspergillus nidulans by directly comparing a bovine chymosin-producing strain with its parental wild-type strain in continuous culture by using expressed sequence tag microarrays. This approach demonstrated more subtle and specific changes in gene expression than those observed when mimicking the effects of protein overproduction by using a secretion blocker. The impact of overexpressing a secreted recombinant protein more closely resembles the unfolded-protein response in vivo.
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Affiliation(s)
- Andrew H Sims
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester M13 9PT, UK
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Ward OP, Qin WM, Dhanjoon J, Ye J, Singh A. Physiology and Biotechnology of Aspergillus. ADVANCES IN APPLIED MICROBIOLOGY 2005; 58C:1-75. [PMID: 16543029 DOI: 10.1016/s0065-2164(05)58001-8] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- O P Ward
- Department of Biology, University of Waterloo Waterloo, Ontario, Canada N2L 3G1
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