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Arentshorst M, Kooloth Valappil P, Mózsik L, Regensburg-Tuïnk TJG, Seekles SJ, Tjallinks G, Fraaije MW, Visser J, Ram AFJ. A CRISPR/Cas9-based multicopy integration system for protein production in Aspergillus niger. FEBS J 2023; 290:5127-5140. [PMID: 37335926 DOI: 10.1111/febs.16891] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 04/25/2023] [Accepted: 06/16/2023] [Indexed: 06/21/2023]
Abstract
The filamentous fungus Aspergillus niger is well known for its high protein secretion capacity and a preferred host for homologous and heterologous protein production. To improve the protein production capacity of A. niger even further, a set of dedicated protein production strains was made containing up to 10 glucoamylase landing sites (GLSs) at predetermined sites in the genome. These GLSs replace genes encoding enzymes abundantly present or encoding unwanted functions. Each GLS contains the promotor and terminator region of the glucoamylase gene (glaA), one of the highest expressed genes in A. niger. Integrating multiple gene copies, often realized by random integration, is known to boost protein production yields. In our approach the GLSs allow for rapid targeted gene replacement using CRISPR/Cas9-mediated genome editing. By introducing the same or different unique DNA sequences (dubbed KORE sequences) in each GLS and designing Cas9-compatible single guide RNAs, one is able to select at which GLS integration of a target gene occurs. In this way a set of identical strains with different copy numbers of the gene of interest can be easily and rapidly made to compare protein production levels. As an illustration of its potential, we successfully used the expression platform to generate multicopy A. niger strains producing the Penicillium expansum PatE::6xHis protein catalysing the final step in patulin biosynthesis. The A. niger strain expressing 10 copies of the patE::6xHis expression cassette produced about 70 μg·mL-1 PatE protein in the culture medium with a purity just under 90%.
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Affiliation(s)
- Mark Arentshorst
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Prajeesh Kooloth Valappil
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - László Mózsik
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Tonny J G Regensburg-Tuïnk
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Sjoerd J Seekles
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Gwen Tjallinks
- Molecular Enzymology, University of Groningen, The Netherlands
| | - Marco W Fraaije
- Molecular Enzymology, University of Groningen, The Netherlands
| | - Jaap Visser
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
| | - Arthur F J Ram
- Microbial Sciences, Fungal Genetics and Biotechnology, Institute of Biology Leiden, Leiden University, The Netherlands
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Sgro M, Chow N, Olyaei F, Arentshorst M, Geoffrion N, Ram AFJ, Powlowski J, Tsang A. Functional analysis of the protocatechuate branch of the β-ketoadipate pathway in Aspergillus niger. J Biol Chem 2023; 299:105003. [PMID: 37399977 PMCID: PMC10406623 DOI: 10.1016/j.jbc.2023.105003] [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: 02/06/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/05/2023] Open
Abstract
Bacteria and fungi catabolize plant-derived aromatic compounds by funneling into one of seven dihydroxylated aromatic intermediates, which then undergo ring fission and conversion to TCA cycle intermediates. Two of these intermediates, protocatechuic acid and catechol, converge on β-ketoadipate which is further cleaved to succinyl-CoA and acetyl-CoA. These β-ketoadipate pathways have been well characterized in bacteria. The corresponding knowledge of these pathways in fungi is incomplete. Characterization of these pathways in fungi would expand our knowledge and improve the valorization of lignin-derived compounds. Here, we used homology to characterize bacterial or fungal genes to predict the genes involved in the β-ketoadipate pathway for protocatechuate utilization in the filamentous fungus Aspergillus niger. We further used the following approaches to refine the assignment of the pathway genes: whole transcriptome sequencing to reveal genes upregulated in the presence of protocatechuic acid; deletion of candidate genes to observe their ability to grow on protocatechuic acid; determination by mass spectrometry of metabolites accumulated by deletion mutants; and enzyme assays of the recombinant proteins encoded by candidate genes. Based on the aggregate experimental evidence, we assigned the genes for the five pathway enzymes as follows: NRRL3_01405 (prcA) encodes protocatechuate 3,4-dioxygenase; NRRL3_02586 (cmcA) encodes 3-carboxy-cis,cis-muconate cyclase; NRRL3_01409 (chdA) encodes 3-carboxymuconolactone hydrolase/decarboxylase; NRRL3_01886 (kstA) encodes β-ketoadipate:succinyl-CoA transferase; and NRRL3_01526 (kctA) encodes β-ketoadipyl-CoA thiolase. Strain carrying ΔNRRL3_00837 could not grow on protocatechuic acid, suggesting that it is essential for protocatechuate catabolism. Its function is unknown as recombinant NRRL3_00837 did not affect the in vitro conversion of protocatechuic acid to β-ketoadipate.
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Affiliation(s)
- Michael Sgro
- Department of Biology, Concordia University, Montreal, Quebec, Canada; Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Nicholas Chow
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Farnaz Olyaei
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Mark Arentshorst
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, The Netherlands
| | - Nicholas Geoffrion
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
| | - Arthur F J Ram
- Institute of Biology Leiden, Microbial Sciences, Leiden University, Leiden, The Netherlands
| | - Justin Powlowski
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada; Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Adrian Tsang
- Department of Biology, Concordia University, Montreal, Quebec, Canada; Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada.
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Cairns TC, de Kanter T, Zheng XZ, Zheng P, Sun J, Meyer V. Regression modelling of conditional morphogene expression links and quantifies the impact of growth rate, fitness and macromorphology with protein secretion in Aspergillus niger. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:95. [PMID: 37268954 DOI: 10.1186/s13068-023-02345-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/18/2023] [Indexed: 06/04/2023]
Abstract
BACKGROUND Filamentous fungi are used as industrial cell factories to produce a diverse portfolio of proteins, organic acids, and secondary metabolites in submerged fermentation. Generating optimized strains for maximum product titres relies on a complex interplay of molecular, cellular, morphological, and macromorphological factors that are not yet fully understood. RESULTS In this study, we generate six conditional expression mutants in the protein producing ascomycete Aspergillus niger and use them as tools to reverse engineer factors which impact total secreted protein during submerged growth. By harnessing gene coexpression network data, we bioinformatically predicted six morphology and productivity associated 'morphogenes', and placed them under control of a conditional Tet-on gene switch using CRISPR-Cas genome editing. Strains were phenotypically screened on solid and liquid media following titration of morphogene expression, generating quantitative measurements of growth rate, filamentous morphology, response to various abiotic perturbations, Euclidean parameters of submerged macromorphologies, and total secreted protein. These data were built into a multiple linear regression model, which identified radial growth rate and fitness under heat stress as positively correlated with protein titres. In contrast, diameter of submerged pellets and cell wall integrity were negatively associated with productivity. Remarkably, our model predicts over 60% of variation in A. niger secreted protein titres is dependent on these four variables, suggesting that they play crucial roles in productivity and are high priority processes to be targeted in future engineering programs. Additionally, this study suggests A. niger dlpA and crzA genes are promising new leads for enhancing protein titres during fermentation. CONCLUSIONS Taken together this study has identified several potential genetic leads for maximizing protein titres, delivered a suite of chassis strains with user controllable macromorphologies during pilot fermentation studies, and has quantified four crucial factors which impact secreted protein titres in A. niger.
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Affiliation(s)
- Timothy C Cairns
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße Des 17. Juni 135, 10623, Berlin, Germany.
| | - Tom de Kanter
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße Des 17. Juni 135, 10623, Berlin, Germany
| | - Xiaomei Z Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China
| | - Vera Meyer
- Chair of Applied and Molecular Microbiology, Institute of Biotechnology, Technische Universität Berlin, Straße Des 17. Juni 135, 10623, Berlin, Germany.
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Orekhova A, De Angelis M, Cacciotti A, Reverberi M, Rotili D, Giorgi A, Protto V, Bonincontro G, Fiorentino F, Zgoda V, Mai A, Palamara AT, Simonetti G. Modulation of Virulence-Associated Traits in Aspergillus fumigatus by BET Inhibitor JQ1. Microorganisms 2022; 10:2292. [PMID: 36422362 PMCID: PMC9698166 DOI: 10.3390/microorganisms10112292] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/13/2022] [Accepted: 11/15/2022] [Indexed: 08/18/2024] Open
Abstract
Aspergillus fumigatus is a disease-causing, opportunistic fungus that can establish infection due to its capacity to respond to a wide range of environmental conditions. Secreted proteins and metabolites, which play a critical role in fungal-host interactions and pathogenesis, are modulated by epigenetic players, such as bromodomain and extraterminal domain (BET) proteins. In this study, we evaluated the in vitro and in vivo capability of the BET inhibitor JQ1 to modulate the extracellular proteins and virulence of A. fumigatus. The abundance of 25 of the 76 extracellular proteins identified through LC-MS/MS proteomic analysis changed following JQ1 treatment. Among them, a ribonuclease, a chitinase, and a superoxide dismutase were dramatically downregulated. Moreover, the proteomic analysis of A. fumigatus intracellular proteins indicated that Abr2, an intracellular laccase involved in the last step of melanin synthesis, was absent in the JQ1-treated group. To investigate at which level this downregulation occurred and considering the ability of JQ1 to modulate gene expression we checked the level of ABR2, Chitinase, and Superoxide dismutase mRNA expression by qRT-PCR. Finally, the capacity of JQ1 to reduce the virulence of A. fumigatus has been proved using Galleria mellonella larvae, which are an in vivo model to evaluate fungal virulence. Overall, the promising activity exhibited by JQ1 suggests that A. fumigatus is sensitive to BET inhibition and BET proteins may be a viable target for developing antifungal agents.
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Affiliation(s)
- Anastasia Orekhova
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Marta De Angelis
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Andrea Cacciotti
- Department of Environmental Biology, “Sapienza” University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
| | - Massimo Reverberi
- Department of Environmental Biology, “Sapienza” University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
| | - Dante Rotili
- Department of Drug Chemistry and Technologies, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Alessandra Giorgi
- Department of Biochemical Sciences, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Virginia Protto
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Graziana Bonincontro
- Department of Environmental Biology, “Sapienza” University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
| | - Francesco Fiorentino
- Department of Drug Chemistry and Technologies, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Victor Zgoda
- Institute of Biomedical Chemistry, Moscow, 10 Pogodinskaya Street, Moscow 119121, Russia
| | - Antonello Mai
- Department of Drug Chemistry and Technologies, “Sapienza” University of Rome, 00185 Rome, Italy
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, “Sapienza” University of Rome, 00185 Rome, Italy
- Department of Infectious Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Giovanna Simonetti
- Department of Environmental Biology, “Sapienza” University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy
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Seekles SJ, Punt M, Savelkoel N, Houbraken J, Wösten HAB, Ohm RA, Ram AFJ. Genome sequences of 24 Aspergillus niger sensu stricto strains to study strain diversity, heterokaryon compatibility, and sexual reproduction. G3 (BETHESDA, MD.) 2022; 12:jkac124. [PMID: 35608315 PMCID: PMC9258588 DOI: 10.1093/g3journal/jkac124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 05/10/2022] [Indexed: 12/02/2022]
Abstract
Mating-type distribution within a phylogenetic tree, heterokaryon compatibility, and subsequent diploid formation were studied in 24 Aspergillus niger sensu stricto strains. The genomes of the 24 strains were sequenced and analyzed revealing an average of 6.1 ± 2.0 variants/kb between Aspergillus niger sensu stricto strains. The genome sequences were used together with available genome data to generate a phylogenetic tree revealing 3 distinct clades within Aspergillus niger sensu stricto. The phylogenetic tree revealed that both MAT1-1 and MAT1-2 mating types were present in each of the 3 clades. The phylogenetic differences were used to select for strains to analyze heterokaryon compatibility. Conidial color markers (fwnA and brnA) and auxotrophic markers (pyrG and nicB) were introduced via CRISPR/Cas9-based genome editing in a selection of strains. Twenty-three parasexual crosses using 11 different strains were performed. Only a single parasexual cross between genetically highly similar strains resulted in a successful formation of heterokaryotic mycelium and subsequent diploid formation, indicating widespread heterokaryon incompatibility as well as multiple active heterokaryon incompatibility systems between Aspergillus niger sensu stricto strains. The 2 vegetatively compatible strains were of 2 different mating types and a stable diploid was isolated from this heterokaryon. Sclerotium formation was induced on agar media containing Triton X-100; however, the sclerotia remained sterile and no ascospores were observed. Nevertheless, this is the first report of a diploid Aspergillus niger sensu stricto strain with 2 different mating types, which offers the unique possibility to screen for conditions that might lead to ascospore formation in A. niger.
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Affiliation(s)
- Sjoerd J Seekles
- TIFN, 6708 PW, Wageningen, the Netherlands
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, 2333 BE, Leiden, the Netherlands
| | - Maarten Punt
- TIFN, 6708 PW, Wageningen, the Netherlands
- Microbiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Niki Savelkoel
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, 2333 BE, Leiden, the Netherlands
| | - Jos Houbraken
- TIFN, 6708 PW, Wageningen, the Netherlands
- Applied & Industrial Mycology, Westerdijk Fungal Biodiversity Institute, 3584 CT, Utrecht, the Netherlands
| | - Han A B Wösten
- TIFN, 6708 PW, Wageningen, the Netherlands
- Microbiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Robin A Ohm
- TIFN, 6708 PW, Wageningen, the Netherlands
- Microbiology, Department of Biology, Utrecht University, 3584 CH, Utrecht, the Netherlands
| | - Arthur F J Ram
- TIFN, 6708 PW, Wageningen, the Netherlands
- Department Molecular Microbiology and Biotechnology, Institute of Biology, Leiden University, 2333 BE, Leiden, the Netherlands
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A Special Phenotype of Aconidial Aspergillus niger SH2 and Its Mechanism of Formation via CRISPRi. J Fungi (Basel) 2022; 8:jof8070679. [PMID: 35887436 PMCID: PMC9319794 DOI: 10.3390/jof8070679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 11/17/2022] Open
Abstract
The complex morphological structure of Aspergillus niger influences its production of proteins, metabolites, etc., making the genetic manipulation and clonal purification of this species increasingly difficult, especially in aconidial Aspergillus niger. In this study, we found that N-acetyl-D-glucosamine (GlcNAc) could induce the formation of spore-like propagules in the aconidial Aspergillus niger SH2 strain. The spore-like propagules possessed life activities such as drug resistance, genetic transformation, and germination. Transcriptomic analysis indicated that the spore-like propagules were resting conidia entering dormancy and becoming more tolerant to environmental stresses. The Dac1 gene and the metabolic pathway of GlcNAc converted to glycolysis are related to the formation of the spore-like propagules, as evidenced by the CRISPRi system, qPCR, and semi-quantitative RT-PCR. Moreover, a method based on the CRISPR-Cas9 tool to rapidly recycle screening tags and recover genes was suitable for Aspergillus niger SH2. To sum up, this suggests that the spore-like propagules are resting conidia and the mechanism of their formation is the metabolic pathway of GlcNAc converted to glycolysis, particularly the Dac1 gene. This study can improve our understanding of the critical factors involved in mechanisms of phenotypic change and provides a good model for researching phenotypic change in filamentous fungi.
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