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Konishi K, Yasutake Y, Muramatsu S, Murata S, Yoshida K, Ishiya K, Aburatani S, Sakasegawa SI, Tamura T. Disruption of SMC-related genes promotes recombinant cholesterol esterase production in Burkholderia stabilis. Appl Microbiol Biotechnol 2022; 106:8093-8110. [PMID: 36399168 DOI: 10.1007/s00253-022-12277-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 11/01/2022] [Accepted: 11/04/2022] [Indexed: 11/19/2022]
Abstract
Burkholderia stabilis strain FERMP-21014 secretes cholesterol esterase (BsChe), which is used in clinical settings to determine serum cholesterol levels. Previously, we constructed an expression plasmid with an endogenous constitutive promoter to enable the production of recombinant BsChe. In this study, we obtained one mutant strain with 13.1-fold higher BsChe activity than the wild type, using N-methyl-N'-nitro-N-nitrosoguanidine as a mutagen. DNA-sequencing analysis revealed that the strain had lost chromosome 3 (∆Chr3), suggesting that the genes hindering BsChe production may be encoded on Chr3. We also identified common mutations in the functionally unknown BSFP_068720/30 genes in the top 10 active strains generated during transposon mutagenesis. As BSFP_068720/30/40 comprised an operon on Chr3, we created the BSFP_068720/30/40 disruption mutant and confirmed that each disruption mutant containing the expression plasmid exhibited ~ 16.1-fold higher BsChe activity than the wild type. Quantitative PCR showed that each disruption mutant and ΔChr3 had a ~ 9.4-fold higher plasmid copy number than the wild type. Structural prediction models indicate that BSFP_068730/40 is structurally homologous to the structural maintenance of chromosomes (SMC) protein MukBE, which is responsible for chromosome segregation during cell division. Conversely, BSFP_068720/30/40 disruption did not lead to a Chr3 drop-out. These results imply that BSFP_068720/30/40 is not a SMC protein but is involved in destabilizing foreign plasmids to prevent the influx of genetic information from the environment. In conclusion, the disruption of BSFP_068720/30/40 improved plasmid stability and copy number, resulting in exceptionally high BsChe production. KEY POINTS: • Disruption of BSFP_068720/30/40 enabled mass production of Burkholderia Che/Lip. • BSFP_068730/40 is an SMC protein homolog not involved in chromosome retention. • BSFP_068720/30/40 is likely responsible for the exclusion of exogenous plasmids.
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Affiliation(s)
- Kenji Konishi
- Asahi Kasei Pharma Corporation, Shizuoka, 410-2321, Japan.,Laboratory of Molecular Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan
| | - Yoshiaki Yasutake
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan.,Computational Bio Big-Data Open Innovation Laboratory (CBBD-OIL), AIST, Tokyo, 169-8555, Japan
| | | | - Satomi Murata
- Asahi Kasei Pharma Corporation, Shizuoka, 410-2321, Japan
| | - Keitaro Yoshida
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan
| | - Koji Ishiya
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan
| | - Sachiyo Aburatani
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan
| | | | - Tomohiro Tamura
- Laboratory of Molecular Environmental Microbiology, Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan. .,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, 062-8517, Japan.
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Slović A, Košutić-Gulija T, Forčić D, Šantak M, Jagušić M, Jurković M, Pali D, Ivančić-Jelečki J. Population Variability Generated during Rescue Process and Passaging of Recombinant Mumps Viruses. Viruses 2021; 13:2550. [PMID: 34960819 PMCID: PMC8707793 DOI: 10.3390/v13122550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/10/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
Recombinant mumps viruses (MuVs) based on established vaccine strains represent attractive vector candidates as they have known track records for high efficacy and the viral genome does not integrate in the host cells. We developed a rescue system based on the consensus sequence of the L-Zagreb vaccine and generated seven different recombinant MuVs by (a) insertion of one or two additional transcription units (ATUs), (b) lengthening of a noncoding region to the extent that the longest noncoding region in MuV genome is created, or (c) replacement of original L-Zagreb sequences with sequences rich in CG and AT dinucleotides. All viruses were successfully rescued and faithfully matched sequences of input plasmids. In primary rescued stocks, low percentages of heterogeneous positions were found (maximum 0.12%) and substitutions were predominantly obtained in minor variants, with maximally four substitutions seen in consensus. ATUs did not accumulate more mutations than the natural MuV genes. Six substitutions characteristic for recombinant viruses generated in our system were defined, as they repetitively occurred during rescue processes. In subsequent passaging of primary rescue stocks in Vero cells, different inconsistencies within quasispecies structures were observed. In order to assure that unwanted mutations did not emerge and accumulate, sub-consensus variability should be closely monitored. As we show for Pro408Leu mutation in L gene and a stop codon in one of ATUs, positively selected variants can rise to frequencies over 85% in only few passages.
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Affiliation(s)
- Anamarija Slović
- Centre for Research and Knowledge Transfer in Biotechnology, University of Zagreb, 10000 Zagreb, Croatia; (A.S.); (T.K.-G.); (D.F.); (M.J.); (M.J.); (D.P.)
| | - Tanja Košutić-Gulija
- Centre for Research and Knowledge Transfer in Biotechnology, University of Zagreb, 10000 Zagreb, Croatia; (A.S.); (T.K.-G.); (D.F.); (M.J.); (M.J.); (D.P.)
| | - Dubravko Forčić
- Centre for Research and Knowledge Transfer in Biotechnology, University of Zagreb, 10000 Zagreb, Croatia; (A.S.); (T.K.-G.); (D.F.); (M.J.); (M.J.); (D.P.)
| | - Maja Šantak
- Ruđer Bošković Institute, 10000 Zagreb, Croatia;
| | - Maja Jagušić
- Centre for Research and Knowledge Transfer in Biotechnology, University of Zagreb, 10000 Zagreb, Croatia; (A.S.); (T.K.-G.); (D.F.); (M.J.); (M.J.); (D.P.)
| | - Mirna Jurković
- Centre for Research and Knowledge Transfer in Biotechnology, University of Zagreb, 10000 Zagreb, Croatia; (A.S.); (T.K.-G.); (D.F.); (M.J.); (M.J.); (D.P.)
| | - Dorotea Pali
- Centre for Research and Knowledge Transfer in Biotechnology, University of Zagreb, 10000 Zagreb, Croatia; (A.S.); (T.K.-G.); (D.F.); (M.J.); (M.J.); (D.P.)
| | - Jelena Ivančić-Jelečki
- Centre for Research and Knowledge Transfer in Biotechnology, University of Zagreb, 10000 Zagreb, Croatia; (A.S.); (T.K.-G.); (D.F.); (M.J.); (M.J.); (D.P.)
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Burton TD, Eyre NS. Applications of Deep Mutational Scanning in Virology. Viruses 2021; 13:1020. [PMID: 34071591 PMCID: PMC8227372 DOI: 10.3390/v13061020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/26/2021] [Accepted: 05/26/2021] [Indexed: 12/20/2022] Open
Abstract
Several recently developed high-throughput techniques have changed the field of molecular virology. For example, proteomics studies reveal complete interactomes of a viral protein, genome-wide CRISPR knockout and activation screens probe the importance of every single human gene in aiding or fighting a virus, and ChIP-seq experiments reveal genome-wide epigenetic changes in response to infection. Deep mutational scanning is a relatively novel form of protein science which allows the in-depth functional analysis of every nucleotide within a viral gene or genome, revealing regions of importance, flexibility, and mutational potential. In this review, we discuss the application of this technique to RNA viruses including members of the Flaviviridae family, Influenza A Virus and Severe Acute Respiratory Syndrome Coronavirus 2. We also briefly discuss the reverse genetics systems which allow for analysis of viral replication cycles, next-generation sequencing technologies and the bioinformatics tools that facilitate this research.
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Affiliation(s)
| | - Nicholas S. Eyre
- College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia;
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