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Duran Ş, Üstüntanir Dede AF, Dündar Orhan Y, Arslanyolu M. Genome-wide identification and in-silico analysis of papain-family cysteine protease encoding genes in Tetrahymena thermophila. Eur J Protistol 2024; 92:126033. [PMID: 38088016 DOI: 10.1016/j.ejop.2023.126033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/06/2023] [Accepted: 11/02/2023] [Indexed: 02/06/2024]
Abstract
Tetrahymena thermophila is a promising host for recombinant protein production, but its utilization in biotechnology is mostly limited due to the presence of intracellular and extracellular papain-family cysteine proteases (PFCPs). In this study, we employed bioinformatics approaches to investigate the T. thermophila PFCP genes and their encoded proteases (TtPFCPs), the most prominent protease family in the genome. Results from the multiple sequence alignment, protein modeling, and conserved motif analyses revealed that all TtPFCPs showed considerably high homology with mammalian cysteine cathepsins and contained conserved amino acid motifs. The total of 121 TtPFCP-encoding genes, 14 of which were classified as non-peptidase homologs, were found. Remaining 107 true TtPFCPs were divided into four distinct subgroups depending on their homology with mammalian lysosomal cathepsins: cathepsin L-like (TtCATLs), cathepsin B-like (TtCATBs), cathepsin C-like (TtCATCs), and cathepsin X-like (TtCATXs) PFCPs. The majority of true TtPFCPs (96 out of the total) were in TtCATL-like peptidase subgroup. Both phylogenetic and chromosomal localization analyses of TtPFCPs supported the hypothesis that TtPFCPs likely evolved through tandem gene duplication events and predominantly accumulated on micronuclear chromosome 5. Additionally, more than half of the identified TtPFCP genes are expressed in considerably low quantities compared to the rest of the TtPFCP genes, which are expressed at a higher level. However, their expression patterns fluctuate based on the stage of the life cycle. In conclusion, this study provides the first comprehensive in-silico analysis of TtPFCP genes and encoded proteases. The results would help designing an effective strategy for protease knockout mutant cell lines to discover biological function and to improve the recombinant protein production in T. thermophila.
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Affiliation(s)
- Şeyma Duran
- Department of Molecular Biology, Graduate School of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Türkiye.
| | - Ayça Fulya Üstüntanir Dede
- Department of Molecular Biology, Graduate School of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Türkiye.
| | - Yeliz Dündar Orhan
- Department of Advanced Technologies, Graduate School of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Türkiye.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunusemre Campus, Eskişehir 26470, Türkiye.
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2
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The C-Type Lysozyme from the upper Gastrointestinal Tract of Opisthocomus hoatzin, the Stinkbird. Int J Mol Sci 2019; 20:ijms20225531. [PMID: 31698762 PMCID: PMC6887759 DOI: 10.3390/ijms20225531] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 10/31/2019] [Accepted: 11/01/2019] [Indexed: 01/07/2023] Open
Abstract
Muramidases/lysozymes are important bio-molecules, which cleave the glycan backbone in the peptidoglycan polymer found in bacterial cell walls. The glycoside hydrolase (GH) family 22 C-type lysozyme, from the folivorous bird Opisthocomus hoazin (stinkbird), was expressed in Aspergillus oryzae, and a set of variants was produced. All variants were enzymatically active, including those designed to probe key differences between the Hoatzin enzyme and Hen Egg White lysozyme. Four variants showed improved thermostability at pH 4.7, compared to the wild type. The X-ray structure of the enzyme was determined in the apo form and in complex with chitin oligomers. Bioinformatic analysis of avian GH22 amino acid sequences showed that they separate out into three distinct subgroups (chicken-like birds, sea birds and other birds). The Hoatzin is found in the "other birds" group and we propose that this represents a new cluster of avian upper-gut enzymes.
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3
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Effect of pepA deletion and overexpression in Aspergillus luchuensis on sweet potato shochu brewing. J Biosci Bioeng 2019; 128:456-462. [PMID: 31031195 DOI: 10.1016/j.jbiosc.2019.03.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/12/2019] [Accepted: 03/28/2019] [Indexed: 11/20/2022]
Abstract
The mash of sweet potato shochu (Japanese distilled spirit) has a low pH value because the shochu koji mold produces a large amount of citric acid, which prevents germ contamination. In this study, we examined acid protease PepA's role in shochu production. For this purpose, we constructed pepA deletion and overexpression strains, using a black koji mold Aspergillus luchuensis RIB 2604 (NBRC 4314), with the Agrobacterium-mediated transformation method. The rice koji, prepared using a pepA disruptant (ΔpepA) and pepA-overexpressing strain (OEpepA), demonstrated 1/2- and 24-fold acid protease activities compared to that prepared using the parental strain, respectively. A small-scale test of sweet potato shochu brewing indicated the mash of ΔpepA had a lower amino acid concentration, while the mash of OEpepA had a higher concentration than that produced by the parental strain. Therefore, the mash amino acid concentrations were proportional to these strains' acid proteases activities. After distilling these mashes, we examined each shochu's aroma components. Shochu prepared using ΔpepA had relatively higher aroma components, such as alcohol and ester, compared to that prepared using parental strains. Meanwhile, shochu prepared using OEpepA had lower aroma components than that prepared using the parental strains. Based on these results, the amount of shochu aroma components showed an inverse correlation to the acid protease activity in the mash. Thus, the koji mold's acid protease content had a greater influence on the aroma qualities of sweet potato shochu. Accordingly, we have discussed the possibility of the breeding of shochu koji mold with acid protease as an indicator.
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Mullaney EJ. Survey of theAspergillus NigerGroup for Dna Sequences Cross Hybridizing to the Five Prime Region of the Fungal Phytase Gene. Mycologia 2018. [DOI: 10.1080/00275514.1993.12026248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Edward J. Mullaney
- Southern Regional Research Center, ARS, USDA, P.O. Box 19687. New Orleans, Louisiana 70179
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5
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Reilly MC, Magnuson JK, Baker SE. Approaches to understanding protein hypersecretion in fungi. FUNGAL BIOL REV 2016. [DOI: 10.1016/j.fbr.2016.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Identification of potential cell wall component that allows Taka-amylase A adsorption in submerged cultures of Aspergillus oryzae. Appl Microbiol Biotechnol 2011; 92:961-9. [DOI: 10.1007/s00253-011-3422-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Revised: 06/02/2011] [Accepted: 06/03/2011] [Indexed: 11/26/2022]
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7
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Salame TM, Ziv C, Hadar Y, Yarden O. RNAi as a potential tool for biotechnological applications in fungi. Appl Microbiol Biotechnol 2010; 89:501-12. [DOI: 10.1007/s00253-010-2928-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 09/29/2010] [Accepted: 09/29/2010] [Indexed: 12/28/2022]
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8
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Adav SS, Li AA, Manavalan A, Punt P, Sze SK. Quantitative iTRAQ Secretome Analysis of Aspergillus niger Reveals Novel Hydrolytic Enzymes. J Proteome Res 2010; 9:3932-40. [DOI: 10.1021/pr100148j] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Sunil S. Adav
- School of Biological Sciences, Nanyang Technological Universiy, 60 Nanyang Drive, Singapore 637551, and Department of Molecular Genetics and Gene Technology, TNO Nutrition and Food Research Institute, Utrechtseweg 48, PO Box 360, 3700 AJ Zeist, The Netherlands
| | - An A. Li
- School of Biological Sciences, Nanyang Technological Universiy, 60 Nanyang Drive, Singapore 637551, and Department of Molecular Genetics and Gene Technology, TNO Nutrition and Food Research Institute, Utrechtseweg 48, PO Box 360, 3700 AJ Zeist, The Netherlands
| | - Arulmani Manavalan
- School of Biological Sciences, Nanyang Technological Universiy, 60 Nanyang Drive, Singapore 637551, and Department of Molecular Genetics and Gene Technology, TNO Nutrition and Food Research Institute, Utrechtseweg 48, PO Box 360, 3700 AJ Zeist, The Netherlands
| | - Peter Punt
- School of Biological Sciences, Nanyang Technological Universiy, 60 Nanyang Drive, Singapore 637551, and Department of Molecular Genetics and Gene Technology, TNO Nutrition and Food Research Institute, Utrechtseweg 48, PO Box 360, 3700 AJ Zeist, The Netherlands
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological Universiy, 60 Nanyang Drive, Singapore 637551, and Department of Molecular Genetics and Gene Technology, TNO Nutrition and Food Research Institute, Utrechtseweg 48, PO Box 360, 3700 AJ Zeist, The Netherlands
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9
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Ribeiro O, Wiebe M, Ilmén M, Domingues L, Penttilä M. Expression of Trichoderma reesei cellulases CBHI and EGI in Ashbya gossypii. Appl Microbiol Biotechnol 2010; 87:1437-46. [DOI: 10.1007/s00253-010-2610-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 04/08/2010] [Accepted: 04/09/2010] [Indexed: 12/17/2022]
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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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Construction of quintuple protease gene disruptant for heterologous protein production in Aspergillus oryzae. Appl Microbiol Biotechnol 2009; 82:691-701. [DOI: 10.1007/s00253-008-1815-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2008] [Revised: 11/27/2008] [Accepted: 12/07/2008] [Indexed: 10/21/2022]
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12
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Punt PJ, Schuren FH, Lehmbeck J, Christensen T, Hjort C, van den Hondel CA. Characterization of the Aspergillus niger prtT, a unique regulator of extracellular protease encoding genes. Fungal Genet Biol 2008; 45:1591-9. [DOI: 10.1016/j.fgb.2008.09.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 09/12/2008] [Accepted: 09/22/2008] [Indexed: 11/28/2022]
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13
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Monitoring global gene expression of proteases and improvement of human lysozyme production in the nptB gene disruptant of Aspergillus oryzae. Biosci Biotechnol Biochem 2008; 72:499-505. [PMID: 18256487 DOI: 10.1271/bbb.70582] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Aspergillus oryzae has numerous protease genes that might cause proteolytic degradation of heterologously-produced proteins. The productivity of the heterologous protein can be improved by protease gene disruption, but it is difficult to select disruption targets efficiently. In this study, we monitored the expression of 132 protease genes by DNA microarray. A group of protease genes up-regulated during cultivation was identified by clustering analysis. In this protease group, the nptB gene encoding neutral protease II was included as well as the alpA, tppA, and pepA genes, disruption of which has improved human lysozyme (HLY) production. The nptB gene was disrupted to investigate its involvement in HLY production, and nptB disruptants showed an improvement in the production. These observations suggest that monitoring the expression of protease genes is an efficient strategy in screening potential disruption targets for heterologous protein production in A. oryzae.
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The effects of bioprocess parameters on extracellular proteases in a recombinant Aspergillus niger B1-D. Appl Microbiol Biotechnol 2008; 78:333-41. [DOI: 10.1007/s00253-007-1298-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 11/10/2007] [Accepted: 11/22/2007] [Indexed: 11/27/2022]
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15
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Wang Y, Xue W, Sims AH, Zhao C, Wang A, Tang G, Qin J, Wang H. Isolation of four pepsin-like protease genes from Aspergillus niger and analysis of the effect of disruptions on heterologous laccase expression. Fungal Genet Biol 2008; 45:17-27. [DOI: 10.1016/j.fgb.2007.09.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2007] [Revised: 09/24/2007] [Accepted: 09/24/2007] [Indexed: 10/22/2022]
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16
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Jin FJ, Watanabe T, Juvvadi PR, Maruyama JI, Arioka M, Kitamoto K. Double disruption of the proteinase genes, tppA and pepE, increases the production level of human lysozyme by Aspergillus oryzae. Appl Microbiol Biotechnol 2007; 76:1059-68. [PMID: 17622525 DOI: 10.1007/s00253-007-1088-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 06/09/2007] [Accepted: 06/10/2007] [Indexed: 10/23/2022]
Abstract
In this study, we investigated the effects of proteinase gene disruption on heterologous protein production by Aspergillus oryzae. The human lysozyme (HLY) was selected for recombinant production as a model for the heterologous protein. A tandem HLY construct fused with alpha-amylase (AmyB) was expressed by A. oryzae in which the Kex2 cleavage site was inserted at the upstream of HLY. HLY was successfully processed from AmyB and produced in the medium. We performed a systematic disruption analysis of five proteinase genes (pepA, pepE, alpA, tppA, and palB) in the HLY-producing strain with the adeA selectable marker. Comparative analysis indicated that disruption of the tppA gene encoding a tripeptidyl peptidase resulted in the highest increase (36%) in the HLY production. We further deleted the tppA gene in the pepE or palB disruptant with another selectable marker, argB. Consequently, a double disruption of the tppA and pepE genes led to a 63% increase in the HLY production compared to the control strain. This is the first study to report that the double disruption of the tppA and pepE genes improved the production level of a heterologous protein by filamentous fungi.
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Affiliation(s)
- Feng Jie Jin
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Tokyo 113-8657, Japan
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17
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El-Enshasy H, Kleine J, Rinas U. Agitation effects on morphology and protein productive fractions of filamentous and pelleted growth forms of recombinant Aspergillus niger. Process Biochem 2006. [DOI: 10.1016/j.procbio.2006.05.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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18
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Kim YS, Cha HJ. Solubility dependency of co-expression effects of stress-induced protein Dps on foreign protein expression in Escherichia coli. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2005.11.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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19
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Joosten V, Roelofs MS, van den Dries N, Goosen T, Verrips CT, van den Hondel CAMJJ, Lokman BC. Production of bifunctional proteins by Aspergillus awamori: Llama variable heavy chain antibody fragment (VHH) R9 coupled to Arthromyces ramosus peroxidase (ARP). J Biotechnol 2005; 120:347-59. [PMID: 16169108 DOI: 10.1016/j.jbiotec.2005.06.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Revised: 06/02/2005] [Accepted: 06/21/2005] [Indexed: 10/25/2022]
Abstract
The Arthromyces ramosus peroxidase gene (arp) was genetically fused to either the 5'- or 3'-terminal ends of the gene encoding llama variable heavy chain antibody fragment V(HH) R9, resulting in the fusion expression cassettes ARP-R9 or R9-ARP. Aspergillus awamori transformants were obtained which produced up to 30 mgl(-1) fusion protein in the culture medium. Both fusion proteins showed peroxidase activity in an ABTS activity test. Considerable amounts of fusion protein were detected intracellularly, suggesting that the fungus encounters problems in secreting these kind of proteins. ELISA experiments showed that ARP-R9 was less able to bind its antigen, the azo-dye RR6, as compared to R9-ARP. Furthermore, in contrast to R9-ARP, ARP-R9 bound to RR6 did not show peroxidase activity anymore. These results indicate that fusion of ARP to the C-terminus of the antibody fragment V(HH) R9 (R9-ARP) is the preferred orientation.
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Affiliation(s)
- Vivi Joosten
- TNO Quality of Life, Department of Microbiology, Utrechtseweg 48, P.O.Box 360, 3700 AJ Zeist, The Netherlands.
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20
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Parra R, Aldred D, Magan N. A novel immobilised design for the production of the heterologous protein lysozyme by a genetically engineered Aspergillus niger strain. Appl Microbiol Biotechnol 2004; 67:336-44. [PMID: 15480630 DOI: 10.1007/s00253-004-1742-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2004] [Revised: 08/19/2004] [Accepted: 08/31/2004] [Indexed: 10/26/2022]
Abstract
A novel immobilisation design for increasing the final concentration of the heterologous protein lysozyme by a genetically engineered fungus, Aspergillus niger B1, was developed. A central composition design was used to investigate different immobilised polymer types (alginate and pectate), polymer concentration [24% and 4% (w/v)], inoculum support ratios (1:2 and 1:4) and gel-inducing agent concentration [CaCl(2), 2% and 3.5% (w/v)]. Studies of the kinetics of production showed that optimum lysozyme productivity occurred after 10 days. Lysozyme production was significantly affected by polymer type, polymer concentration, and inoculum support ratio. Overall, immobilisation in Ca-pectate resulted in higher lysozyme production compared to that in Ca-alginate. Similar effects were observed when the polymer concentration was reduced. Regardless of polymer type and concentration, increasing the fungal inoculum level increased lysozyme production. A significantly higher lysozyme yield was achieved with Ca-pectate in comparison to Ca-alginate (approximately 20-23 mg l(-1) and 0.5-2 mg l(-1), respectively). The maximum lysozyme yield achieved was about 23 mg l(-1) by immobilisation in Ca-pectate 2% (w/v) with 33% (v/v) mycelium and 3.5% (w/v) gel-inducing agent (CaCl(2)). Response surface methodology was used to investigate the effect of pH and water activity (a(w)). The best medium pH was 4.5-5.0, and bead a(w) for optimum lysozyme yield was 0.94, regardless of polymer type.
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Affiliation(s)
- Roberto Parra
- Applied Mycology Group, Institute of BioScience and Technology, Cranfield University, Silsoe, Bedford MK45 4DT, UK
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21
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Joosten V, Gouka RJ, van den Hondel CAMJJ, Verrips CT, Lokman BC. Expression and production of llama variable heavy-chain antibody fragments (VHHs) by Aspergillus awamori. Appl Microbiol Biotechnol 2004; 66:384-92. [PMID: 15378291 DOI: 10.1007/s00253-004-1689-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 06/11/2004] [Accepted: 06/11/2004] [Indexed: 10/26/2022]
Abstract
We report the expression and production of llama variable heavy-chain antibody fragments (V(HH)s) by Aspergillus awamori. Fragments encoding V(HH)s were cloned in a suitable Aspergillus expression vector and transformants secreting V(HH) fragments were analysed for integrated gene copy-numbers, mRNA levels and protein production. Functional V(HH)s were detected in the culture medium, indicating the feasibility of producing this type of protein in a fungal expression system. Secreted V(HH)s were subjected to (extracellular) degradation, which could be partially prevented by the addition of BSA to the culture medium.
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Affiliation(s)
- Vivi Joosten
- Department of Microbiology, TNO Nutrition and Food Research, P.O. Box 360, 3700 AJ, Zeist, The Netherlands
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22
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Valkonen M, Ward M, Wang H, Penttilä M, Saloheimo M. Improvement of foreign-protein production in Aspergillus niger var. awamori by constitutive induction of the unfolded-protein response. Appl Environ Microbiol 2004; 69:6979-86. [PMID: 14660339 PMCID: PMC309985 DOI: 10.1128/aem.69.12.6979-6986.2003] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Unfolded-protein response (UPR) denotes the upregulation of endoplasmic reticulum (ER)-resident chaperone and foldase genes and numerous other genes involved in secretory functions during the accumulation of unfolded proteins into the ER. Overexpression of individual foldases and chaperones has been used in attempts to improve protein production in different production systems. We describe here a novel strategy to improve foreign-protein production. We show that the constitutive induction of the UPR pathway in Aspergillus niger var. awamori can be achieved by expressing the activated form of the transcription factor hacA. This induction enhances the production of Trametes versicolor laccase by up to sevenfold and of bovine preprochymosin by up to 2.8-fold in this biotechnically important fungus. The regulatory range of UPR was studied by analyzing the mRNA levels of novel A. niger var. awamori genes involved in different secretory functions. This revealed both similarities and differences to corresponding studies in Saccharomyces cerevisiae.
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Paloheimo M, Mäntylä A, Kallio J, Suominen P. High-yield production of a bacterial xylanase in the filamentous fungus Trichoderma reesei requires a carrier polypeptide with an intact domain structure. Appl Environ Microbiol 2004; 69:7073-82. [PMID: 14660351 PMCID: PMC309970 DOI: 10.1128/aem.69.12.7073-7082.2003] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A bacterial xylanase gene, Nonomuraea flexuosa xyn11A, was expressed in the filamentous fungus Trichoderma reesei from the strong cellobiohydrolase 1 promoter as fusions to a variety of carrier polypeptides. By using single-copy isogenic transformants, it was shown that production of this xylanase was clearly increased (up to 820 mg/liter) when it was produced as a fusion protein with a carrier polypeptide having an intact domain structure compared to the production (150 to 300 mg/liter) of fusions to the signal sequence alone or to carriers having incomplete domain structures. The carriers tested were the T. reesei mannanase I (Man5A, or MANI) core-hinge and a fragment thereof and the cellulose binding domain of T. reesei cellobiohydrolase II (Cel6A, or CBHII) with and without the hinge region(s) and a fragment thereof. The flexible hinge region was shown to have a positive effect on both the production of Xyn11A and the efficiency of cleavage of the fusion polypeptide. The recombinant Xyn11A produced had properties similar to those of the native xylanase. It constituted 6 to 10% of the total proteins secreted by the transformants. About three times more of the Man5A core-hinge carrier polypeptide than of the recombinant Xyn11A was observed. Even in the best Xyn11A producers, the levels of the fusion mRNAs were only approximately 10% of the level of cel7A (cbh1) mRNA in the untransformed host strain.
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Enhancement of heterologous protein expression in Escherichia coli by co-expression of nonspecific DNA-binding stress protein, Dps. Enzyme Microb Technol 2003. [DOI: 10.1016/s0141-0229(03)00148-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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25
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Affiliation(s)
- Masayuki Machida
- Research Center for Glycoscience, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1, Higashi, Tsukuba, Ibaraki, 305-8566, Japan
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Abstract
Fungal autolysis is the natural process of self-digestion of aged hyphal cultures, occurring as a result of hydrolase activity, causing vacuolation and disruption of organelle and cell wall structure. Previously, authors have considered individual aspects of fungal lysis, in terms of either an enzyme, a process or an organism. This review considers both the physiology and morphology of fungal autolysis, with an emphasis on correlations between enzymological profiles and the morphological changes occurring during culture degeneration. The involvement of the main groups of autolytic hydrolases is examined (i.e., proteases, glucanases, and chitinases), in addition to the effects of autolysis on the morphology and products of industrial bioprocesses. We call for a concerted approach to the study of autolysis, as this will be fundamental for research to progress in this field. Increased understanding will allow for greater control of the prevention, or induction of fungal autolysis. Such advances will be applicable in the development of antifungal medicines and enable increased productivity and yields in industrial bioprocesses. Using paradigms in existing model systems, including mammalian cell death and aging in yeast, areas for future study are suggested in order to advance the study of fungal cell death.
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Affiliation(s)
- Stewart White
- Eli Lilly and Company, Fleming Road, Speke, Liverpool, UK.
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Moralejo FJ, Cardoza RE, Gutierrez S, Lombraña M, Fierro F, Martín JF. Silencing of the aspergillopepsin B (pepB) gene of Aspergillus awamori by antisense RNA expression or protease removal by gene disruption results in a large increase in thaumatin production. Appl Environ Microbiol 2002; 68:3550-9. [PMID: 12089041 PMCID: PMC126795 DOI: 10.1128/aem.68.7.3550-3559.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillopepsin B was identified in culture broths of Aspergillus awamori by in situ detection of its proteolytic activity and by immunodetection with anti-aspergillopepsin B antibodies. Severe thaumatin degradation was observed after in vitro treatment of thaumatin with purified aspergillopepsin B. The pepB gene encoding aspergillopepsin B of A. awamori was cloned and characterized. It is located in chromosome IV of A. awamori, as shown by pulsed-field gel electrophoresis, and encodes a protein of 282 amino acids with high similarity to the aspergillopepsin B of Aspergillus niger var. macrosporus. The pepB gene is expressed at high rates as a monocistronic 1.0-kb transcript in media with casein at acidic pH values. An antisense cassette constructed by inserting the pepB gene in the antisense orientation downstream from the gpdA promoter resulted in a good level of antisense mRNA, as shown by reverse transcription-PCR. Partial silencing of the pepB gene by the antisense mRNA resulted in a 31% increase in thaumatin yield. However, significant residual degradation of thaumatin still occurred. To completely remove aspergillopepsin B, the pepB gene was deleted by double crossover. Two of the selected transformants lacked the endogenous pepB gene and did not form aspergillopepsin B. Thaumatin yields increased by between 45% in transformant APB 7/25 and 125% in transformant 7/36 with respect to the parental strain. Reduction of proteolytic degradation by gene silencing with antisense mRNA or total removal of the aspergillopepsin B by directed gene deletion was a very useful method for improving thaumatin production in A. awamori.
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Affiliation(s)
- Francisco J Moralejo
- Instituto de Biotecnología de León INBIOTEC, Parque Científico de León, Aveñida del Real no. 1, 24006 León, Spain
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Abstract
In the mid-1970s, information technology and recombinant DNA technology were considered as the breakthrough technologies of the final quarter of the 20th century. Now, about 25 years later, information technology has penetrated deeply into our society and nearly everyone uses this technology. Compared to the formidable success of information technology, the progress in the commercialization of recombinant DNA technology is moderate, even when taking into account that all that is related to the technological application of biological sciences needs extensive safety testing. However, there are signs that the speed of this commercialization will increase in the first decade of the 21st century. Moreover, new breakthroughs in our understanding of the complete genetic make up of eukaryotes will contribute to this increase in speed. An important aspect of the commercialization of this technology is the development of cells as factories for the production of valuable and/or useful molecules. Lower eukaryotes, such as yeasts and molds, are the most promising candidates to become the factories of the future, but at present these factories still contains a lot of process lines that may be superfluous under the well controlled conditions in fermentors. On the other hand, the speed and yield of these cellular production lines can be increased by eliminating the rate-determining steps of these process lines. In this contribution to the European Union symposium from Cell to Factory, some steps in the improvement of S. cerevisiae as cell factories for (heterologous) hydrophobic molecules are presented.
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Dubey AK, Suresh C, Kavitha R, Karanth NG, Umesh-Kumar S. Evidence that the glucoamylases and alpha-amylase secreted by Aspergillus niger are proteolytically processed products of a precursor enzyme. FEBS Lett 2000; 471:251-5. [PMID: 10767433 DOI: 10.1016/s0014-5793(00)01410-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A 125-kDa starch hydrolysing enzyme of Aspergillus niger characterised by its ability to dextrinise and saccharify starch [Suresh et al. (1999) Appl. Microbiol. Biotechnol. 51, 673-675] was also found to possess activity towards raw starch. Segregation of these activities in the 71-kDa glucoamylase and a 53-kDa alpha-amylase-like enzyme supported by antibody cross-reactivity studies and the isolation of mutants based on assay screens for the secretion of particular enzyme forms revealed the 125-kDa starch hydrolysing enzyme as their precursor. N-terminal sequence analysis further revealed that the 71-kDa glucoamylase was the N-terminal product of the precursor enzyme. Immunological cross reactivity of the 53-kDa amylase with antibodies raised against the precursor enzyme but not with the 71- and 61-kDa glucoamylase antibodies suggested that this enzyme activity is represented by the C-terminal fragment of the precursor. The N-terminal sequence of the 53-kDa protein showed similarity to the reported Taka amylase of Aspergillus oryzae. Antibody cross-reactivity to a 10-kDa non-enzymic peptide and a 61-kDa glucoamylase described these proteins as products of the 71-kDa glucoamylase. Identification of only the precursor starch hydrolysing enzyme in the protein extracts of fungal protoplasts suggested proteolytic processing in the cellular periplasmic space as the cause for the secretion of multiple forms of amylases by A. niger.
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Affiliation(s)
- A K Dubey
- Department of Food Microbiology, Central Food Technological Research Institute, Mysore, India.
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30
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Asgeirsdóttir SA, Scholtmeijer K, Wessels JG. A sandwiched-culture technique for evaluation of heterologous protein production in a filamentous fungus. Appl Environ Microbiol 1999; 65:2250-2. [PMID: 10224030 PMCID: PMC91327 DOI: 10.1128/aem.65.5.2250-2252.1999] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aspergillus niger is known for its efficient excretion machinery. However, problems have often arisen in obtaining high amounts of heterologous proteins in the culture medium. Here we present a quick method using sandwiched colonies to evaluate transgenic strains for secretion of heterologous proteins. Expressing the ABH1 hydrophobin of Agaricus bisporus in A. niger, we showed that low production levels of the heterologous protein are probably due to extracellular proteolytic degradation of the protein.
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Affiliation(s)
- S A Asgeirsdóttir
- Molecular Plant Biology Laboratory, Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9751 NN Haren, The Netherlands.
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31
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van Gemeren IA, Beijersbergen A, van den Hondel CA, Verrips CT. Expression and secretion of defined cutinase variants by Aspergillus awamori. Appl Environ Microbiol 1998; 64:2794-9. [PMID: 9687432 PMCID: PMC106774 DOI: 10.1128/aem.64.8.2794-2799.1998] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Several cutinase variants derived by molecular modelling and site-directed mutagenesis of a cutinase gene from Fusarium solani pisi are poorly secreted by Saccharomyces cerevisiae. The majority of these variants are successfully produced by the filamentous fungus Aspergillus awamori. However, the L51S and T179Y mutations caused reductions in the levels of extracellular production of two cutinase variants by A. awamori. Metabolic labelling studies were performed to analyze the bottleneck in enzyme production by the fungus in detail. These studies showed that because of the single L51S substitution, rapid extracellular degradation of cutinase occurred. The T179Y substitution did not result in enhanced sensitivity towards extracellular proteases. Presumably, the delay in the extracellular accumulation of this cutinase variant is caused by the enhanced hydrophobicity of the molecule. Overexpression of the A. awamori gene encoding the chaperone BiP in the cutinase-producing A. awamori strains had no significant effect on the secretion efficiency of the cutinases. A cutinase variant with the amino acid changes G28A, A85F, V184I, A185L, and L189F that was known to aggregate in the endoplasmic reticulum of S. cerevisiae, resulting in low extracellular protein levels, was successfully produced by A. awamori. An initial bottleneck in secretion occurred before or during translocation into the endoplasmic reticulum but was rapidly overcome by the fungus.
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Affiliation(s)
- I A van Gemeren
- Department of Biotechnology, Unilever Research, 3133 AT Vlaardingen, The Netherlands.
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32
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Griffen AM, Novakova M, Mokhtar SI, Wiebe MG, Robson GD, Trinci AP. Protease-deficient mutants of the Quorn® mycoprotein fungus, Fusarium graminearumA3/5. FEMS Microbiol Lett 1998. [DOI: 10.1111/j.1574-6968.1998.tb12825.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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33
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Abstract
Enzymes from filamentous fungi are already widely exploited, but new applications for known enzymes and new enzymic activities continue to be found. In addition, enzymes from less amenable non-fungal sources require heterologous production and fungi are being used as the production hosts. In each case there is a need to improve production and to ensure quality of product. While conventional, mutagenesis-based, strain improvement methods will continue to be applied to enzyme production from filamentous fungi the application of recombinant DNA techniques is beginning to reveal important information on the molecular basis of fungal enzyme production and this knowledge is now being applied both in the laboratory and commercially. We review the current state of knowledge on the molecular basis of enzyme production by filamentous fungi. We focus on transcriptional and post-transcriptional regulation of protein production, the transit of proteins through the secretory pathway and the structure of the proteins produced including glycosylation.
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Affiliation(s)
- D B Archer
- Genetics and Microbiology Department, Institute of Food Research, Norwich, UK
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34
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Griffen AM, Wiebe MG, Robson GD, Trinci APJ. Extracellular proteases produced by the Quorn® myco-protein fungus Fusarium graminearum in batch and chemostat culture. Microbiology (Reading) 1997; 143:3007-3013. [DOI: 10.1099/00221287-143-9-3007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Summary: Fusarium graminearum was grown in batch and continuous (chemostat) culture on a glucose-mineral salts medium in the presence and absence of casein. In the absence of casein no protease activity was detected in the culture filtrate from either batch or chemostat culture. For batch cultures grown on medium containing casein, most of the proteolytic activity detected in the supernatant during exponential growth had an optimum at ca pH 5.0. However, as the cultures passed from late exponential into stationary phase, the pH profile of the protease activity broadened until most of it was in the alkaline pH region. For glucose-limited chemostat cultures grown on media containing casein, protease activity had a narrow pH optimum with maximum activity at pH 5.0. For all concentrations of casein examined, protease activity was greater in chemostat culture than in batch culture. Extracellular proteases from batch and chemostat cultures were purified by bacitracin-Sepharose affinity chromatography. At least seven proteins were purified from batch cultures but chemostat cultures contained only a single aspartic protease with a molecular mass of 40 kDa.
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Affiliation(s)
- Alison M. Griffen
- The School of Biological Sciences, 1.800 Stopford Building, University of Manchester, Manchester M13 9PT, UK
| | - Marilyn G. Wiebe
- The School of Biological Sciences, 1.800 Stopford Building, University of Manchester, Manchester M13 9PT, UK
| | - Geoffrey D. Robson
- The School of Biological Sciences, 1.800 Stopford Building, University of Manchester, Manchester M13 9PT, UK
| | - Anthony P. J. Trinci
- The School of Biological Sciences, 1.800 Stopford Building, University of Manchester, Manchester M13 9PT, UK
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35
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van den Hombergh JP, van de Vondervoort PJ, Fraissinet-Tachet L, Visser J. Aspergillus as a host for heterologous protein production: the problem of proteases. Trends Biotechnol 1997; 15:256-63. [PMID: 9237405 DOI: 10.1016/s0167-7799(97)01020-2] [Citation(s) in RCA: 146] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Homologous and heterologous protein production by filamentous fungi is often limited by the expression of proteases at high levels. By eliminating specific protease activities, protein production in Aspergillus niger can be improved considerably. Both classical mutagenesis and gene disruption techniques have yielded strains with reduced protease expression. Combinations of these mutations and disruptions result in a further reduction of protease activity. The coupling of efficient promoters to target genes allows their expression under conditions that repress the expression of several proteases, which further improves product yields. The strategies used have led to the development of a set of tester strains from which the appropriate genetic background for production can be selected.
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Affiliation(s)
- J P van den Hombergh
- Molecular Genetics of Industrial Microorganisms Section, Wagenigen Agricultural University, The Netherlands
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36
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Gouka RJ, Punt PJ, Hessing JG, van den Hondel CA. Analysis of heterologous protein production in defined recombinant Aspergillus awamori strains. Appl Environ Microbiol 1996; 62:1951-7. [PMID: 8787393 PMCID: PMC167973 DOI: 10.1128/aem.62.6.1951-1957.1996] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A study was carried out to obtain more insight into the parameters that determine the secretion of heterologous proteins from filamentous fungi. A strategy was chosen in which the mRNA levels and protein levels of a number of heterologous genes of different origins were compared. All genes were under control of the Aspergillus awamori 1,4-beta-endoxylanase A (exlA) expression signals and were integrated in a single copy at the A. awamori pyrG locus. A Northern (RNA) analysis showed that large differences occurred in the steady-state mRNA levels obtained with the various genes; those levels varied from high values for genes of fungal origin (A. awamori 1,4-beta-endoxylanase A, Aspergillus niger glucoamylase, and Thermomyces lanuginosa lipase) to low values for genes of nonfungal origin (human interleukin 6 and Cyamopsis tetragonoloba [guar] alpha-galactosidase). With the C. tetragonoloba alpha-galactosidase wild-type gene full-length mRNA was even undetectable. Surprisingly, small amounts of full-length mRNA could be detected when a C. tetragonoloba alpha-galactosidase gene with an optimized Saccharomyces cerevisiae codon preference was expressed. In all cases except human interleukin 6, the protein levels corresponded to the amounts expected on basis of the mRNA levels. For human interleukin 6, very low protein levels were observed, whereas relatively high steady-state mRNA levels were obtained. Our data suggest that intracellular protein degradation is the most likely explanation for the low levels of secreted human interleukin 6.
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Affiliation(s)
- R J Gouka
- TNO Nutrition and Food Research Institute, Department of Molecular Genetics and Gene Technology, Rijswijk, The Netherlands
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37
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MacKenzie DA, Spencer JA, Le Gal-Coëffet MF, Archer DB. Efficient production from Aspergillus niger of a heterologous protein and an individual protein domain, heavy isotope-labelled, for structure-function analysis. J Biotechnol 1996; 46:85-93. [PMID: 8672288 DOI: 10.1016/0168-1656(95)00179-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Aspergillus niger has been used successfully to secrete proteins labelled with 13C and/or 15N to a specific activity of > 99% for high resolution NMR analysis. In the case of a heterologous protein, hen egg-white lysozyme, 15N single-labelled and 13C, 15N double-labelled forms were secreted at yields of 100-200 mg l-1 by optimising the type of carbon source used and the ratio of carbon to nitrogen. Another protein, the glucoamylase starch-binding domain from A. niger, was also produced as the 15N single-labelled form at 20-40 mg l-1.
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Affiliation(s)
- D A MacKenzie
- Institute of Food Research, Norwich Research Park, Colney, UK
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38
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Effect of culture conditions and induction strategies on production of human interleukin-6 by a recombinant Aspergillus nidulans strain. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s0953-7562(96)80169-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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39
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Jara P, Gilbert S, Delmas P, Guillemot JC, Kaghad M, Ferrara P, Loison G. Cloning and characterization of the eapB and eapC genes of Cryphonectria parasitica encoding two new acid proteinases, and disruption of eapC. MOLECULAR & GENERAL GENETICS : MGG 1996; 250:97-105. [PMID: 8569693 DOI: 10.1007/bf02191829] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Two new proteinases secreted by Cryphonectria parasitica, namely EapB and EapC, have been purified. The corresponding structural genes were isolated by screening a cosmid library, and sequenced. Comparison of genomic and cDNA sequences revealed that the eapB and eapC genes contain three and two introns, respectively. The products of the eapB and eapC genes as deduced from the nucleotide sequences, are 268 and 269 residues long, respectively. N-terminal amino acid sequencing data indicates that EapC is synthesized as a zymogen, which yields a mature 206-amino acid enzyme after cleavage of the prepro sequence. Similarly, sequence alignment studies suggest that EapB is secreted as a 203-residue form which shares extensive similarities not only with EapC but also with two other acid fungal proteinases. However, they display distinct structural features; for example, no cysteine residue is found in EapC. The eapC gene was mutated using a two-step gene replacement strategy which allowed the specific introduction of several stop codons at the beginning of the eapC coding sequence in an endothiapepsin-deficient (EapA-) C. parasitica strain. Although the resulting strain did not secrete EapC, it still exhibited residual extracellular proteolytic activity, which could be due to EapB.
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Affiliation(s)
- P Jara
- Sanofi Recherche, Centre de Labège, France
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40
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Archer DB, MacKenzie DA, Ridout MJ. Heterologous protein secretion by Aspergillus niger growing in submerged culture as dispersed or aggregated mycelia. Appl Microbiol Biotechnol 1995; 44:157-60. [PMID: 8579829 DOI: 10.1007/bf00164495] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The secreted production of a heterologous enzyme, hen egg-white lysozyme, by Aspergillus niger was studied in shake flasks containing media of different initial viscosities. Raising the viscosity of the medium by addition of polyvinylpyrrolidone (PVP) brought about a transition in the form of growth from aggregated mycelia (pellets) to dispersed mycelia. The specific yield of lysozyme in cultures containing an initial concentration of 5% (w/v) starch was 8 mg lysozyme/g dry weight. Addition of 2% (w/v) PVP to the medium resulted in a specific yield of 14 mg lysozyme/g dry weight.
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Affiliation(s)
- D B Archer
- Institute of Food Research, Colney, Norwich, UK
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41
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van den Hombergh JP, van de Vondervoort PJ, van der Heijden NC, Visser J. New protease mutants in Aspergillus niger result in strongly reduced in vitro degradation of target proteins; genetical and biochemical characterization of seven complementation groups. Curr Genet 1995; 28:299-308. [PMID: 8590475 DOI: 10.1007/bf00326427] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Several mutants of Aspergillus niger, deficient in extracellular protease expression, have been isolated and characterized both genetically and biochemically. The mutant strains, obtained after in vivo UV-mutagenesis of conidiospores and selected by haloscreening on a new dual-substrate plate assay, belong to at least seven different complementation groups. These seven prt loci were assigned to linkage groups using master strains with marked chromosomes. One prt locus (prtC) could be assigned to linkage group I, three (prtB, prtE and prtG) to linkage group III, one (prtF) to linkage group V and the two remaining loci (prtA and prtD) to linkage group VIII. Extracellular proteolytic activities varied from 2 to 3% up to 80% of the protease activity of the parental strain. Assigning the different prt mutants to structural or regulatory genes is difficult since only one structural gene, pepA, has been mapped unambiguously on linkage group I but is not identical to prtC. All prt mutants except for prtC are likely to be regulatory mutants or else belong to a proteolytic cascade because residual activities showed that more proteolytic activities were affected simultaneously. Double mutants were constructed both by recombination and by a second round of mutagenesis. In both cases mutants with further reduced extracellular proteolytic activities were isolated. A sensitive in vitro degradation assay, based on the homologous pectin lyase B (PELB) protein to analyze proteolytic degradation in A. niger, was developed and used to show extremely reduced proteolytic PELB degradation in the culture media of some of these mutants.
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Affiliation(s)
- J P van den Hombergh
- Molecular Genetics of Industrial Microorganisms Agricultural University, HA Wageningen, The Netherlands
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42
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MacKenzie DA, Gendron LC, Jeenes DJ, Archer DB. Physiological optimization of secreted protein production by Aspergillus niger. Enzyme Microb Technol 1994; 16:276-80. [PMID: 7764633 DOI: 10.1016/0141-0229(94)90166-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Physiological factors affecting hen eggwhite lysozyme and native glucoamylase production by Aspergillus niger have been examined in batch culture. Expression of the genes encoding both proteins was controlled by the glucoamylase promoter. In standard expression medium (ACMS/N/P), secreted lysozyme yields were found to be maximal at 20-25 degrees C (8-10 mg l-1) and markedly reduced at 30-37 degrees C (3-5 mg l-1). Production of lysozyme exhibited similar induction or repression profiles to that of endogenous glucoamylase such that secreted lysozyme yields could be ordered with respect to growth on the following carbon sources: soluble starch > maltose > glucose >> xylose. Significantly higher yields of up to 30-60 mg l-1 were obtained in a richer medium containing soya milk, although in contrast to growth in ACMS/N/P, the highest levels of secreted lysozyme were achieved at 37 degrees C. This improvement is attributed partly to an increase in culture biomass concentration and to a reduction in medium acidification. Growth in this medium produced a markedly different pellet morphology.
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Affiliation(s)
- D A MacKenzie
- Department of Genetics and Microbiology, Agricultural and Food Research Council, Norwich Laboratory, UK
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43
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Archer DB, Jeenes DJ, Mackenzie DA. Strategies for improving heterologous protein production from filamentous fungi. Antonie Van Leeuwenhoek 1994; 65:245-50. [PMID: 7847891 DOI: 10.1007/bf00871952] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Despite the naturally high capacity for protein secretion by many species of filamentous fungi, secreted yields of many heterologous proteins have been comparatively low. The strategies for yield improvement have included the use of strong homologous promoters, increased gene copy number, gene fusions with a gene encoding a naturally well-secreted protein, protease-deficient host strains and screening for high yields following random mutagenesis. Such approaches have been effective with some target heterologous proteins but not others. Approaches used in heterologous protein production from filamentous fungi are discussed and a perspective on emerging strategies is presented.
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Affiliation(s)
- D B Archer
- Institute of Food Research, Colney, Norwich, UK
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44
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Swinkels BW, van Ooyen AJ, Bonekamp FJ. The yeast Kluyveromyces lactis as an efficient host for heterologous gene expression. Antonie Van Leeuwenhoek 1993; 64:187-201. [PMID: 8092859 DOI: 10.1007/bf00873027] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several different yeast species have been developed into systems for efficient heterologous gene expression. In this paper we review foreign gene expression in the dairy yeast Kluyveromyces lactis. This yeast presents several advantageous properties in comparison to other yeast species. These include its impressive secretory capacities, its excellent fermentation characteristics on large scale, its food grade status and the availability of both episomal and integrative expression vectors. Moreover, in contrast to the methylotrophic yeasts that are frequently used for the expression of foreign genes, K. lactis does not require explosion-proof fermentation equipment. Here, we present an overview of the available tools for heterologous gene expression in K. lactis (available promoters, vector systems, etc). Also, the production of prochymosin, human serum albumin and pancreatic phospholipase by K. lactis is discussed in more detail, and used to rate the achievements of K. lactis with respect to other micro-organisms in which these proteins have been produced.
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Affiliation(s)
- B W Swinkels
- Gist-Brocades B.V., Research and Development, Delft, The Netherlands
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45
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Roberts IN, Jeenes DJ, MacKenzie DA, Wilkinson AP, Sumner IG, Archer DB. Heterologous gene expression in Aspergillus niger: a glucoamylase-porcine pancreatic prophospholipase A2 fusion protein is secreted and processed to yield mature enzyme. Gene X 1992; 122:155-61. [PMID: 1452022 DOI: 10.1016/0378-1119(92)90043-o] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The cDNA gene encoding porcine pancreatic prophospholipase A2 (proPLA2) was cloned into an Aspergillus niger expression vector downstream of the glucoamylase (glaA) gene promoter region. When this construct was transformed into A. niger, no detectable PLA2 was produced. Evidence was obtained showing that the PLA2 gene was transcribed and that PLA2 is extremely susceptible to both intracellular and extracellular proteases of A. niger, thus indicating that translation products would be rapidly degraded. By fusing the proPLA2-encoding sequence to the entire glaA gene, secreted yields of PLA2 up to 10 micrograms/ml were obtained from a transformed protease-deficient strain of A. niger. PLA2 was secreted in young cultures as a fusion protein, but in older cultures, it was processed from the glucoamylase carrier protein. Secreted PLA2 was shown to be enzymatically active and to have the correct N-terminal amino acid (aa) sequence, although another form of processed PLA2 was also produced. This form included two aa of the proregion from PLA2. The potential for improving yields of secreted heterologous proteins from A. niger still further is discussed.
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Affiliation(s)
- I N Roberts
- AFRC Institute of Food Research, Norwich Laboratory, UK
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