1
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Roots CT, Barrick JE. CryptKeeper: a negative design tool for reducing unintentional gene expression in bacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.05.611466. [PMID: 39282447 PMCID: PMC11398486 DOI: 10.1101/2024.09.05.611466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/20/2024]
Abstract
Foundational techniques in molecular biology-such as cloning genes, tagging biomolecules for purification or identification, and overexpressing recombinant proteins-rely on introducing non-native or synthetic DNA sequences into organisms. These sequences may be recognized by the transcription and translation machinery in their new context in unintended ways. The cryptic gene expression that sometimes results has been shown to produce genetic instability and mask experimental signals. Computational tools have been developed to predict individual types of gene expression elements, but it can be difficult for researchers to contextualize their collective output. Here, we introduce CryptKeeper, a software pipeline that visualizes predictions of bacterial gene expression signals and estimates the translational burden possible from a DNA sequence. We investigate several published examples where cryptic gene expression in E. coli interfered with experiments. CryptKeeper accurately postdicts unwanted gene expression from both eukaryotic virus infectious clones and individual proteins that led to genetic instability. It also identifies off-target gene expression elements that resulted in truncations that confounded protein purification. Incorporating negative design using CryptKeeper into reverse genetics and synthetic biology workflows can help to mitigate cloning challenges and avoid unexplained failures and complications that arise from unintentional gene expression.
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Affiliation(s)
- Cameron T Roots
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, U.S.A
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, U.S.A
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2
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Kim K, Choe D, Cho S, Palsson B, Cho BK. Reduction-to-synthesis: the dominant approach to genome-scale synthetic biology. Trends Biotechnol 2024; 42:1048-1063. [PMID: 38423803 DOI: 10.1016/j.tibtech.2024.02.008] [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: 12/14/2023] [Revised: 02/09/2024] [Accepted: 02/12/2024] [Indexed: 03/02/2024]
Abstract
Advances in systems and synthetic biology have propelled the construction of reduced bacterial genomes. Genome reduction was initially focused on exploring properties of minimal genomes, but more recently it has been deployed as an engineering strategy to enhance strain performance. This review provides the latest updates on reduced genomes, focusing on dual-track approaches of top-down reduction and bottom-up synthesis for their construction. Using cases from studies that are based on established industrial workhorse strains, we discuss the construction of a series of synthetic phenotypes that are candidates for biotechnological applications. Finally, we address the possible uses of reduced genomes for biotechnological applications and the needed future research directions that may ultimately lead to the total synthesis of rationally designed genomes.
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Affiliation(s)
- Kangsan Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea; KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Donghui Choe
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA
| | - Suhyung Cho
- KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Bernhard Palsson
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Kongens, Lyngby, Denmark
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea; KI for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea; Graduate School of Engineering Biology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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3
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Radde N, Mortensen GA, Bhat D, Shah S, Clements JJ, Leonard SP, McGuffie MJ, Mishler DM, Barrick JE. Measuring the burden of hundreds of BioBricks defines an evolutionary limit on constructability in synthetic biology. Nat Commun 2024; 15:6242. [PMID: 39048554 PMCID: PMC11269670 DOI: 10.1038/s41467-024-50639-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 07/18/2024] [Indexed: 07/27/2024] Open
Abstract
Engineered DNA will slow the growth of a host cell if it redirects limiting resources or otherwise interferes with homeostasis. Escape mutants that alleviate this burden can rapidly evolve and take over cell populations, making genetic engineering less reliable and predictable. Synthetic biologists often use genetic parts encoded on plasmids, but their burden is rarely characterized. We measured how 301 BioBrick plasmids affected Escherichia coli growth and found that 59 (19.6%) were burdensome, primarily because they depleted the limited gene expression resources of host cells. Overall, no BioBricks reduced the growth rate of E. coli by >45%, which agreed with a population genetic model that predicts such plasmids should be unclonable. We made this model available online for education ( https://barricklab.org/burden-model ) and added our burden measurements to the iGEM Registry. Our results establish a fundamental limit on what DNA constructs and genetic modifications can be successfully engineered into cells.
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Affiliation(s)
- Noor Radde
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Genevieve A Mortensen
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Diya Bhat
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Shireen Shah
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Joseph J Clements
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Sean P Leonard
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Matthew J McGuffie
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Dennis M Mishler
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
- The Freshman Research Initiative, College of Natural Sciences, The University of Texas at Austin, Austin, TX, USA
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA.
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4
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Ma S, Su T, Lu X, Qi Q. Bacterial genome reduction for optimal chassis of synthetic biology: a review. Crit Rev Biotechnol 2024; 44:660-673. [PMID: 37380345 DOI: 10.1080/07388551.2023.2208285] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/13/2022] [Accepted: 02/20/2023] [Indexed: 06/30/2023]
Abstract
Bacteria with streamlined genomes, that harbor full functional genes for essential metabolic networks, are able to synthesize the desired products more effectively and thus have advantages as production platforms in industrial applications. To obtain streamlined chassis genomes, a large amount of effort has been made to reduce existing bacterial genomes. This work falls into two categories: rational and random reduction. The identification of essential gene sets and the emergence of various genome-deletion techniques have greatly promoted genome reduction in many bacteria over the past few decades. Some of the constructed genomes possessed desirable properties for industrial applications, such as: increased genome stability, transformation capacity, cell growth, and biomaterial productivity. The decreased growth and perturbations in physiological phenotype of some genome-reduced strains may limit their applications as optimized cell factories. This review presents an assessment of the advancements made to date in bacterial genome reduction to construct optimal chassis for synthetic biology, including: the identification of essential gene sets, the genome-deletion techniques, the properties and industrial applications of artificially streamlined genomes, the obstacles encountered in constructing reduced genomes, and the future perspectives.
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Affiliation(s)
- Shuai Ma
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Tianyuan Su
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Xuemei Lu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
| | - Qingsheng Qi
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, P. R. China
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5
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Philipp LA, Bühler K, Ulber R, Gescher J. Beneficial applications of biofilms. Nat Rev Microbiol 2024; 22:276-290. [PMID: 37957398 DOI: 10.1038/s41579-023-00985-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/05/2023] [Indexed: 11/15/2023]
Abstract
Many microorganisms live in the form of a biofilm. Although they are feared in the medical sector, biofilms that are composed of non-pathogenic organisms can be highly beneficial in many applications, including the production of bulk and fine chemicals. Biofilm systems are natural retentostats in which the biocatalysts can adapt and optimize their metabolism to different conditions over time. The adherent nature of biofilms allows them to be used in continuous systems in which the hydraulic retention time is much shorter than the doubling time of the biocatalysts. Moreover, the resilience of organisms growing in biofilms, together with the potential of uncoupling growth from catalytic activity, offers a wide range of opportunities. The ability to work with continuous systems using a potentially self-advancing whole-cell biocatalyst is attracting interest from a range of disciplines, from applied microbiology to materials science and from bioengineering to process engineering. The field of beneficial biofilms is rapidly evolving, with an increasing number of applications being explored, and the surge in demand for sustainable and biobased solutions and processes is accelerating advances in the field. This Review provides an overview of the research topics, challenges, applications and future directions in beneficial and applied biofilm research.
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Affiliation(s)
- Laura-Alina Philipp
- Hamburg University of Technology, Institute of Technical Microbiology, Hamburg, Germany
| | - Katja Bühler
- Department of Environmental Microbiology, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Roland Ulber
- RPTU Kaiserslautern-Landau, Institute of Bioprocess Engineering, Kaiserslautern, Germany
| | - Johannes Gescher
- Hamburg University of Technology, Institute of Technical Microbiology, Hamburg, Germany.
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Hitomi K, Ishii Y, Ying BW. Experimental evolution for the recovery of growth loss due to genome reduction. eLife 2024; 13:RP93520. [PMID: 38690805 PMCID: PMC11062635 DOI: 10.7554/elife.93520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024] Open
Abstract
As the genome encodes the information crucial for cell growth, a sizeable genomic deficiency often causes a significant decrease in growth fitness. Whether and how the decreased growth fitness caused by genome reduction could be compensated by evolution was investigated here. Experimental evolution with an Escherichia coli strain carrying a reduced genome was conducted in multiple lineages for approximately 1000 generations. The growth rate, which largely declined due to genome reduction, was considerably recovered, associated with the improved carrying capacity. Genome mutations accumulated during evolution were significantly varied across the evolutionary lineages and were randomly localized on the reduced genome. Transcriptome reorganization showed a common evolutionary direction and conserved the chromosomal periodicity, regardless of highly diversified gene categories, regulons, and pathways enriched in the differentially expressed genes. Genome mutations and transcriptome reorganization caused by evolution, which were found to be dissimilar to those caused by genome reduction, must have followed divergent mechanisms in individual evolutionary lineages. Gene network reconstruction successfully identified three gene modules functionally differentiated, which were responsible for the evolutionary changes of the reduced genome in growth fitness, genome mutation, and gene expression, respectively. The diversity in evolutionary approaches improved the growth fitness associated with the homeostatic transcriptome architecture as if the evolutionary compensation for genome reduction was like all roads leading to Rome.
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Affiliation(s)
- Kenya Hitomi
- School of Life and Environmental Sciences, University of TsukubaTsukubaJapan
| | - Yoichiro Ishii
- School of Life and Environmental Sciences, University of TsukubaTsukubaJapan
| | - Bei-Wen Ying
- School of Life and Environmental Sciences, University of TsukubaTsukubaJapan
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7
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Aida H, Ying BW. Efforts to Minimise the Bacterial Genome as a Free-Living Growing System. BIOLOGY 2023; 12:1170. [PMID: 37759570 PMCID: PMC10525146 DOI: 10.3390/biology12091170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/17/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023]
Abstract
Exploring the minimal genetic requirements for cells to maintain free living is an exciting topic in biology. Multiple approaches are employed to address the question of the minimal genome. In addition to constructing the synthetic genome in the test tube, reducing the size of the wild-type genome is a practical approach for obtaining the essential genomic sequence for living cells. The well-studied Escherichia coli has been used as a model organism for genome reduction owing to its fast growth and easy manipulation. Extensive studies have reported how to reduce the bacterial genome and the collections of genomic disturbed strains acquired, which were sufficiently reviewed previously. However, the common issue of growth decrease caused by genetic disturbance remains largely unaddressed. This mini-review discusses the considerable efforts made to improve growth fitness, which was decreased due to genome reduction. The proposal and perspective are clarified for further accumulated genetic deletion to minimise the Escherichia coli genome in terms of genome reduction, experimental evolution, medium optimization, and machine learning.
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Affiliation(s)
| | - Bei-Wen Ying
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Ibaraki, Japan
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8
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Heieck K, Brück T. Localization of Insertion Sequences in Plasmids for L-Cysteine Production in E. coli. Genes (Basel) 2023; 14:1317. [PMID: 37510222 PMCID: PMC10379815 DOI: 10.3390/genes14071317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/19/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Insertion sequence elements (ISE) are often found to be responsible for the collapse of production in synthetically engineered Escherichia coli. By the transposition of ISE into the open reading frame of the synthetic pathway, E. coli cells gain selection advantage over cells expressing the metabolic burdensome production genes. Here, we present the exact entry sites of insertion sequence (IS) families 3 and 5 within plasmids for l-cysteine production in evolved E. coli populations. Furthermore, we identified an uncommon occurrence of an 8-bp direct repeat of IS5 which is atypical for this particular family, potentially indicating a new IS5 target site.
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Affiliation(s)
- Kevin Heieck
- School of Natural Sciences, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Thomas Brück
- School of Natural Sciences, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
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9
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English MA, Alcantar MA, Collins JJ. A self‐propagating, barcoded transposon system for the dynamic rewiring of genomic networks. Mol Syst Biol 2023:e11398. [DOI: 10.15252/msb.202211398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/29/2023] Open
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10
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Heieck K, Arnold ND, Brück TB. Metabolic stress constrains microbial L-cysteine production in Escherichia coli by accelerating transposition through mobile genetic elements. Microb Cell Fact 2023; 22:10. [PMID: 36642733 PMCID: PMC9841684 DOI: 10.1186/s12934-023-02021-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/09/2023] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND L-cysteine is an essential chemical building block in the pharmaceutical-, cosmetic-, food and agricultural sector. Conventionally, L-cysteine production relies on the conversion of keratinous biomass mediated by hydrochloric acid. Today, fermentative production based on recombinant E. coli, where L-cysteine production is streamlined and facilitated by synthetic plasmid constructs, is an alternative process at industrial scale. However, metabolic stress and the resulting production escape mechanisms in evolving populations are severely limiting factors during industrial biomanufacturing. We emulate high generation numbers typically reached in industrial fermentation processes with Escherichia coli harbouring L-cysteine production plasmid constructs. So far no genotypic and phenotypic alterations in early and late L-cysteine producing E. coli populations have been studied. RESULTS In a comparative experimental design, the E. coli K12 production strain W3110 and the reduced genome strain MDS42, almost free of insertion sequences, were used as hosts. Data indicates that W3110 populations acquire growth fitness at the expense of L-cysteine productivity within 60 generations, while production in MDS42 populations remains stable. For the first time, the negative impact of predominantly insertion sequence family 3 and 5 transposases on L-cysteine production is reported, by combining differential transcriptome analysis with NGS based deep plasmid sequencing. Furthermore, metabolic clustering of differentially expressed genes supports the hypothesis, that metabolic stress induces rapid propagation of plasmid rearrangements, leading to reduced L-cysteine yields in evolving populations over industrial fermentation time scales. CONCLUSION The results of this study implicate how selective deletion of insertion sequence families could be a new route for improving industrial L-cysteine or even general amino acid production using recombinant E. coli hosts. Instead of using minimal genome strains, a selective deletion of certain IS families could offer the benefits of adaptive laboratory evolution (ALE) while maintaining enhanced L-cysteine production stability.
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Affiliation(s)
- Kevin Heieck
- grid.6936.a0000000123222966Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Nathanael David Arnold
- grid.6936.a0000000123222966Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Thomas Bartholomäus Brück
- grid.6936.a0000000123222966Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Germany
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11
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Scholz SA, Lindeboom CD, Freddolino PL. Genetic context effects can override canonical cis regulatory elements in Escherichia coli. Nucleic Acids Res 2022; 50:10360-10375. [PMID: 36134716 PMCID: PMC9561378 DOI: 10.1093/nar/gkac787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 08/10/2022] [Accepted: 09/02/2022] [Indexed: 11/12/2022] Open
Abstract
Recent experiments have shown that in addition to control by cis regulatory elements, the local chromosomal context of a gene also has a profound impact on its transcription. Although this chromosome-position dependent expression variation has been empirically mapped at high-resolution, the underlying causes of the variation have not been elucidated. Here, we demonstrate that 1 kb of flanking, non-coding synthetic sequences with a low frequency of guanosine and cytosine (GC) can dramatically reduce reporter expression compared to neutral and high GC-content flanks in Escherichia coli. Natural and artificial genetic context can have a similarly strong effect on reporter expression, regardless of cell growth phase or medium. Despite the strong reduction in the maximal expression level from the fully-induced reporter, low GC synthetic flanks do not affect the time required to reach the maximal expression level after induction. Overall, we demonstrate key determinants of transcriptional propensity that appear to act as tunable modulators of transcription, independent of regulatory sequences such as the promoter. These findings provide insight into the regulation of naturally occurring genes and an independent control for optimizing expression of synthetic biology constructs.
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Affiliation(s)
- Scott A Scholz
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Chase D Lindeboom
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
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12
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Iketani S, Hong SJ, Sheng J, Bahari F, Culbertson B, Atanaki FF, Aditham AK, Kratz AF, Luck MI, Tian R, Goff SP, Montazeri H, Sabo Y, Ho DD, Chavez A. Functional map of SARS-CoV-2 3CL protease reveals tolerant and immutable sites. Cell Host Microbe 2022; 30:1354-1362.e6. [PMID: 36029764 PMCID: PMC9365866 DOI: 10.1016/j.chom.2022.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/20/2022] [Accepted: 08/05/2022] [Indexed: 01/03/2023]
Abstract
The SARS-CoV-2 3CL protease (3CLpro) is an attractive therapeutic target, as it is essential to the virus and highly conserved among coronaviruses. However, our current understanding of its tolerance to mutations is limited. Here, we develop a yeast-based deep mutational scanning approach to systematically profile the activity of all possible single mutants of the 3CLpro and validate a subset of our results within authentic viruses. We reveal that the 3CLpro is highly malleable and is capable of tolerating mutations throughout the protein. Yet, we also identify specific residues that appear immutable, suggesting that these may be targets for future 3CLpro inhibitors. Finally, we utilize our screening as a basis to identify E166V as a resistance-conferring mutation against the clinically used 3CLpro inhibitor, nirmatrelvir. Collectively, the functional map presented herein may serve as a guide to better understand the biological properties of the 3CLpro and for drug development against coronaviruses.
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Affiliation(s)
- Sho Iketani
- Aaron Diamond AIDS Research Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Department of Microbiology and Immunology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Seo Jung Hong
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Jenny Sheng
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Irving Medical Center, New York, NY, USA
| | - Farideh Bahari
- Department of Bioinformatics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Bruce Culbertson
- Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Irving Medical Center, New York, NY, USA; Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY, USA
| | - Fereshteh Fallah Atanaki
- Department of Bioinformatics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Arjun K Aditham
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Alexander F Kratz
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Irving Medical Center, New York, NY, USA
| | - Maria I Luck
- Aaron Diamond AIDS Research Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Ruxiao Tian
- Department of Microbiology and Immunology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Stephen P Goff
- Aaron Diamond AIDS Research Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Department of Microbiology and Immunology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Department of Biochemistry and Molecular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Hesam Montazeri
- Department of Bioinformatics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Yosef Sabo
- Aaron Diamond AIDS Research Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - David D Ho
- Aaron Diamond AIDS Research Center, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Department of Microbiology and Immunology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Alejandro Chavez
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.
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13
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Cloning of Maize TED Transposon into Escherichia coli Reveals the Polychromatic Sequence Landscape of Refractorily Propagated Plasmids. Int J Mol Sci 2022; 23:ijms231911993. [PMID: 36233292 PMCID: PMC9569675 DOI: 10.3390/ijms231911993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/27/2022] [Accepted: 10/06/2022] [Indexed: 11/05/2022] Open
Abstract
MuDR, the founder member of the Mutator superfamily and its MURA transcripts, has been identified as toxic sequences to Escherichia coli (E. coli), which heavily hindered the elucidation of the biochemical features of MURA transposase and confined the broader application of the Mutator system in other organisms. To harness less constrained systems as alternatives, we attempted to clone TED and Jittery, two recently isolated autonomous Mutator-like elements (MULEs) from maize, respectively. Their full-length transcripts and genomic copies are successfully cloned when the incubation time for bacteria to recover from heat shock is extended appropriately prior to plating. However, during their proliferation in E. coli, TED transformed plasmids are unstable, as evidenced by derivatives from which frameshift, deletion mutations, or IS transposon insertions are readily detected. Our results suggest that neither leaky expression of the transposase nor the presence of terminal inverse repeats (TIRs) are responsible for the cloning barriers, which were once ascribed to the presence of the Shine–Dalgarno-like sequence. Instead, the internal sequence of TED (from 1250 to 2845 bp), especially the exons in this region, was the most likely causer. The findings provide novel insights into the property and function of the Mutator superfamily and shed light on the dissection of toxic effects on cloning from MULEs.
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14
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Kwak S, Crook N, Yoneda A, Ahn N, Ning J, Cheng J, Dantas G. Functional mining of novel terpene synthases from metagenomes. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:104. [PMID: 36209178 PMCID: PMC9548185 DOI: 10.1186/s13068-022-02189-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 07/29/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND Terpenes are one of the most diverse and abundant classes of natural biomolecules, collectively enabling a variety of therapeutic, energy, and cosmetic applications. Recent genomics investigations have predicted a large untapped reservoir of bacterial terpene synthases residing in the genomes of uncultivated organisms living in the soil, indicating a vast array of putative terpenoids waiting to be discovered. RESULTS We aimed to develop a high-throughput functional metagenomic screening system for identifying novel terpene synthases from bacterial metagenomes by relieving the toxicity of terpene biosynthesis precursors to the Escherichia coli host. The precursor toxicity was achieved using an inducible operon encoding the prenyl pyrophosphate synthetic pathway and supplementation of the mevalonate precursor. Host strain and screening procedures were finely optimized to minimize false positives arising from spontaneous mutations, which avoid the precursor toxicity. Our functional metagenomic screening of human fecal metagenomes yielded a novel β-farnesene synthase, which does not show amino acid sequence similarity to known β-farnesene synthases. Engineered S. cerevisiae expressing the screened β-farnesene synthase produced 120 mg/L β-farnesene from glucose (2.86 mg/g glucose) with a productivity of 0.721 g/L∙h. CONCLUSIONS A unique functional metagenomic screening procedure was established for screening terpene synthases from metagenomic libraries. This research proves the potential of functional metagenomics as a sequence-independent avenue for isolating targeted enzymes from uncultivated organisms in various environmental habitats.
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Affiliation(s)
- Suryang Kwak
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, 4515 McKinley Avenue, Room 5121, Campus Box 8510, Saint Louis, MO 63110 USA
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO 63110 USA
| | - Nathan Crook
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, 4515 McKinley Avenue, Room 5121, Campus Box 8510, Saint Louis, MO 63110 USA
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO 63110 USA
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 USA
| | - Aki Yoneda
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, 4515 McKinley Avenue, Room 5121, Campus Box 8510, Saint Louis, MO 63110 USA
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO 63110 USA
| | - Naomi Ahn
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, 4515 McKinley Avenue, Room 5121, Campus Box 8510, Saint Louis, MO 63110 USA
| | - Jie Ning
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, 4515 McKinley Avenue, Room 5121, Campus Box 8510, Saint Louis, MO 63110 USA
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO 63110 USA
| | - Jiye Cheng
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, 4515 McKinley Avenue, Room 5121, Campus Box 8510, Saint Louis, MO 63110 USA
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO 63110 USA
| | - Gautam Dantas
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, 4515 McKinley Avenue, Room 5121, Campus Box 8510, Saint Louis, MO 63110 USA
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO 63110 USA
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO 63130 USA
- Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, Saint Louis, MO 63110 USA
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15
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Iketani S, Hong SJ, Sheng J, Bahari F, Culbertson B, Atanaki FF, Aditham AK, Kratz AF, Luck MI, Tian R, Goff SP, Montazeri H, Sabo Y, Ho DD, Chavez A. The Functional Landscape of SARS-CoV-2 3CL Protease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.06.23.497404. [PMID: 35860222 PMCID: PMC9298129 DOI: 10.1101/2022.06.23.497404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) as the etiologic agent of COVID-19 (coronavirus disease 2019) has drastically altered life globally. Numerous efforts have been placed on the development of therapeutics to treat SARS-CoV-2 infection. One particular target is the 3CL protease (3CL pro ), which holds promise as it is essential to the virus and highly conserved among coronaviruses, suggesting that it may be possible to find broad inhibitors that treat not just SARS-CoV-2 but other coronavirus infections as well. While the 3CL protease has been studied by many groups for SARS-CoV-2 and other coronaviruses, our understanding of its tolerance to mutations is limited, knowledge which is particularly important as 3CL protease inhibitors become utilized clinically. Here, we develop a yeast-based deep mutational scanning approach to systematically profile the activity of all possible single mutants of the SARS-CoV-2 3CL pro , and validate our results both in yeast and in authentic viruses. We reveal that the 3CL pro is highly malleable and is capable of tolerating mutations throughout the protein, including within the substrate binding pocket. Yet, we also identify specific residues that appear immutable for function of the protease, suggesting that these interactions may be novel targets for the design of future 3CL pro inhibitors. Finally, we utilize our screening results as a basis to identify E166V as a resistance-conferring mutation against the therapeutic 3CL pro inhibitor, nirmatrelvir, in clinical use. Collectively, the functional map presented herein may serve as a guide for further understanding of the biological properties of the 3CL protease and for drug development for current and future coronavirus pandemics.
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16
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Brkljacic J, Wittler B, Lindsey BE, Ganeshan VD, Sovic MG, Niehaus J, Ajibola W, Bachle SM, Fehér T, Somers DE. Frequency, composition and mobility of Escherichia coli-derived transposable elements in holdings of plasmid repositories. Microb Biotechnol 2022; 15:455-468. [PMID: 34875147 PMCID: PMC8867978 DOI: 10.1111/1751-7915.13962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022] Open
Abstract
By providing the scientific community with uniform and standardized resources of consistent quality, plasmid repositories play an important role in enabling scientific reproducibility. Plasmids containing insertion sequence elements (IS elements) represent a challenge from this perspective, as they can change the plasmid structure and function. In this study, we conducted a systematic analysis of a subset of plasmid stocks distributed by plasmid repositories (The Arabidopsis Biological Resource Center and Addgene) which carry unintended integrations of bacterial mobile genetic elements. The integration of insertion sequences was most often found in, but not limited to, pBR322-derived vectors, and did not affect the function of the specific plasmids. In certain cases, the entire stock was affected, but the majority of the stocks tested contained a mixture of the wild-type and the mutated plasmids, suggesting that the acquisition of IS elements likely occurred after the plasmids were acquired by the repositories. However, comparison of the sequencing results of the original samples revealed that some plasmids already carried insertion mutations at the time of donation. While an extensive BLAST analysis of 47 877 plasmids sequenced from the Addgene repository uncovered IS elements in only 1.12%, suggesting that IS contamination is not widespread, further tests showed that plasmid integration of IS elements can propagate in conventional Escherichia coli hosts over a few tens of generations. Use of IS-free E. coli hosts prevented the emergence of IS insertions as well as that of small indels, suggesting that the use of IS-free hosts by donors and repositories could help limit unexpected and unwanted IS integrations into plasmids.
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Affiliation(s)
| | - Bettina Wittler
- Arabidopsis Biological Resource CenterColumbusOHUSA
- Present address:
Department of Molecular BiologyPrinceton UniversityPrincetonNJUSA
| | | | | | - Michael G. Sovic
- Center For Applied Plant SciencesThe Ohio State UniversityColumbusOHUSA
| | | | - Walliyulahi Ajibola
- Systems and Synthetic Biology UnitInstitute of BiochemistryBiological Research Centre of the Eötvös Lóránd Research NetworkSzegedHungary
- Doctoral School in BiologyUniversity of SzegedSzegedHungary
| | | | - Tamás Fehér
- Systems and Synthetic Biology UnitInstitute of BiochemistryBiological Research Centre of the Eötvös Lóránd Research NetworkSzegedHungary
| | - David E. Somers
- Arabidopsis Biological Resource CenterColumbusOHUSA
- Center For Applied Plant SciencesThe Ohio State UniversityColumbusOHUSA
- Department of Molecular GeneticsThe Ohio State UniversityColumbusOHUSA
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17
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Intracellular Transposition and Capture of Mobile Genetic Elements following Intercellular Conjugation of Multidrug Resistance Conjugative Plasmids from Clinical Enterobacteriaceae Isolates. Microbiol Spectr 2022; 10:e0214021. [PMID: 35044219 PMCID: PMC8768599 DOI: 10.1128/spectrum.02140-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mobile genetic elements (MGEs) are often associated with antimicrobial resistance genes (ARGs). They are responsible for intracellular transposition between different replicons and intercellular conjugation and are therefore important agents of ARG dissemination. Detection and characterization of functional MGEs, especially in clinical isolates, would increase our understanding of the underlying pathways of transposition and recombination and allow us to determine interventional strategies to interrupt this process. Entrapment vectors can be used to capture active MGEs, as they contain a positive selection genetic system conferring a selectable phenotype upon the insertion of an MGE within certain regions of that system. Previously, we developed the pBACpAK entrapment vector that results in a tetracycline-resistant phenotype when MGEs translocate and disrupt the cI repressor gene. We have previously used pBACpAK to capture MGEs in clinical Escherichia coli isolates following transformation with pBACpAK. In this study, we aimed to extend the utilization of pBACpAK to other bacterial taxa. We utilized an MGE-free recipient E. coli strain containing pBACpAK to capture MGEs on conjugative, ARG-containing plasmids following conjugation from clinical Enterobacteriaceae donors. Following the conjugative transfer of multiple conjugative plasmids and screening for tetracycline resistance in these transconjugants, we captured several insertion sequence (IS) elements and novel transposons (Tn7350 and Tn7351) and detected the de novo formation of novel putative composite transposons where the pBACpAK-located tet(A) is flanked by ISKpn25 from the transferred conjugative plasmid, as well as the ISKpn14-mediated integration of an entire 119-kb, blaNDM-1-containing conjugative plasmid from Klebsiella pneumoniae. IMPORTANCE By analyzing transposition activity within our MGE-free recipient, we can gain insights into the interaction and evolution of multidrug resistance-conferring MGEs following conjugation, including the movement of multiple ISs, the formation of composite transposons, and cointegration and/or recombination between different replicons in the same cell. This combination of recipient and entrapment vector will allow fine-scale experimental studies of factors affecting intracellular transposition and MGE formation in and from ARG-encoding MGEs from multiple species of clinically relevant Enterobacteriaceae.
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18
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Qiao W, Liu F, Wan X, Qiao Y, Li R, Wu Z, Saris PEJ, Xu H, Qiao M. Genomic Features and Construction of Streamlined Genome Chassis of Nisin Z Producer Lactococcus lactis N8. Microorganisms 2021; 10:microorganisms10010047. [PMID: 35056496 PMCID: PMC8779420 DOI: 10.3390/microorganisms10010047] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/03/2021] [Accepted: 12/13/2021] [Indexed: 12/02/2022] Open
Abstract
Lactococcus lactis is a commonly used fermenting bacteria in cheese, beverages and meat products. Due to the lack of simplified chassis strains, it has not been widely used in the fields of synthetic biology. Thus, the construction of lactic acid bacteria chassis strains becomes more and more important. In this study, we performed whole genome sequencing, annotation and analysis of L. lactis N8. Based on the genome analysis, we found that L. lactis N8 contains two large plasmids, and the function prediction of the plasmids shows that some regions are related to carbohydrate transport/metabolism, multi-stress resistance and amino acid uptake. L. lactis N8 contains a total of seven prophage-related fragments and twelve genomic islands. A gene cluster encoding a hybrid NRPS–PKS system that was found in L. lactis N8 reveals that the strain has the potential to synthesize novel secondary metabolites. Furthermore, we have constructed a simplified genome chassis of L. lactis N8 and achieved the largest amount of deletion of L. lactis so far. Taken together, the present study offers further insights into the function and potential role of L. lactis N8 as a model strain of lactic acid bacteria and lays the foundation for its application in the field of synthetic biology.
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Affiliation(s)
- Wanjin Qiao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; (W.Q.); (F.L.); (Y.Q.)
| | - Fulu Liu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; (W.Q.); (F.L.); (Y.Q.)
| | - Xing Wan
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, 00014 Helsinki, Finland; (X.W.); (R.L.); (P.E.J.S.)
- Department of Bacteriology and Immunology, Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Yu Qiao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; (W.Q.); (F.L.); (Y.Q.)
| | - Ran Li
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, 00014 Helsinki, Finland; (X.W.); (R.L.); (P.E.J.S.)
| | - Zhenzhou Wu
- State Key Laboratory of Medicinal Chemical Biology and Tianjin Key Laboratory of Protein Sciences, College of Life Sciences, Nankai University, Tianjin 300071, China;
| | - Per Erik Joakim Saris
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, 00014 Helsinki, Finland; (X.W.); (R.L.); (P.E.J.S.)
| | - Haijin Xu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; (W.Q.); (F.L.); (Y.Q.)
- Correspondence: (H.X.); (M.Q.)
| | - Mingqiang Qiao
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China; (W.Q.); (F.L.); (Y.Q.)
- School of Life Sciences, Shanxi University, Taiyuan 030006, China
- Correspondence: (H.X.); (M.Q.)
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19
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Linder M, Haak M, Botes A, Kalinowski J, Rückert C. Construction of an IS-Free Corynebacterium glutamicum ATCC 13 032 Chassis Strain and Random Mutagenesis Using the Endogenous ISCg1 Transposase. Front Bioeng Biotechnol 2021; 9:751334. [PMID: 34976962 PMCID: PMC8715038 DOI: 10.3389/fbioe.2021.751334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 11/02/2021] [Indexed: 11/22/2022] Open
Abstract
Mobile genetic elements (MGEs) contribute to instability of the host genome and plasmids. Previously, removal of the prophages in the industrial amino acid producer Corynebacterium glutamicum ATCC 13 032 resulted in strain MB001 which showed better survival under stress conditions and increased transformability. Still, eight families of Insertion Sequence (IS) elements with 27 potentially active members remain in MB001, two of which were demonstrated to be detrimental in biotechnological processes. In this study, systematical deletion of all complete IS elements in MB001 resulted in the MGE-free strain CR101. CR101 shows growth characteristics identical to the wildtype and the increased transformability of MB001. Due to its improved genome stability, we consider this strain to be an optimal host for basic research and biotechnology. As a “zero-background” host, it is also an ideal basis to study C. glutamicum IS elements. Re-sequencing of CR101 revealed that only five spontaneous point mutations had occurred during the construction process, highlighting the low mutation rate of C. glutamicum on the nucleotide level. In a second step, we developed an easily applicable ISCg1-based transposon mutagenesis system to randomly transpose a selectable marker. For optimal plasmid stability during cloning in Escherichia coli, the system utilizes a genetic switch based on the phage integrase Bxb1. Use of this integrase revealed the presence of a functional attB site in the C. glutamicum genome. To avoid cross-talk with our system and increase ease-of-use, we removed the attB site and also inserted the Bxb1 encoding gene into the chromosome of CR101. Successful insertion of single markers was verified by sequencing randomly selected mutants. Sequencing pooled mutant libraries revealed only a weak target site specificity, seemingly random distribution of insertion sites and no general strand bias. The resulting strain, ML103, together with plasmid pML10 provides a easily customizable system for random mutagenesis in an otherwise genomically stable C. glutamicum. Taken together, the MGE-free C. glutamicum strain CR101, the derivative ML103, and the plasmid pML10 provide a useful set of tools to study C. glutamicum in the future.
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Affiliation(s)
- Marten Linder
- CeBiTec Bielefeld, Technology Platform Genomics, Bielefeld University, Bielefeld, Germany
| | - Markus Haak
- CeBiTec Bielefeld, Technology Platform Genomics, Bielefeld University, Bielefeld, Germany
| | - Angela Botes
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, South Africa
| | - Jörn Kalinowski
- CeBiTec Bielefeld, Technology Platform Genomics, Bielefeld University, Bielefeld, Germany
| | - Christian Rückert
- CeBiTec Bielefeld, Technology Platform Genomics, Bielefeld University, Bielefeld, Germany
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
- *Correspondence: Christian Rückert ,
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20
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Decrulle AL, Frénoy A, Meiller-Legrand TA, Bernheim A, Lotton C, Gutierrez A, Lindner AB. Engineering gene overlaps to sustain genetic constructs in vivo. PLoS Comput Biol 2021; 17:e1009475. [PMID: 34624014 PMCID: PMC8528312 DOI: 10.1371/journal.pcbi.1009475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 10/20/2021] [Accepted: 09/23/2021] [Indexed: 11/20/2022] Open
Abstract
Evolution is often an obstacle to the engineering of stable biological systems due to the selection of mutations inactivating costly gene circuits. Gene overlaps induce important constraints on sequences and their evolution. We show that these constraints can be harnessed to increase the stability of costly genes by purging loss-of-function mutations. We combine computational and synthetic biology approaches to rationally design an overlapping reading frame expressing an essential gene within an existing gene to protect. Our algorithm succeeded in creating overlapping reading frames in 80% of E. coli genes. Experimentally, scoring mutations in both genes of such overlapping construct, we found that a significant fraction of mutations impacting the gene to protect have a deleterious effect on the essential gene. Such an overlap thus protects a costly gene from removal by natural selection by associating the benefit of this removal with a larger or even lethal cost. In our synthetic constructs, the overlap converts many of the possible mutants into evolutionary dead-ends, reducing the evolutionary potential of the system and thus increasing its stability over time. Genomes are translated by triplets of nucleotides on two different strands, allowing for six different reading frames. This permits the existence of gene overlaps, often observed in microbial genomes, where two different proteins are encoded on the same piece of DNA, but in different reading frames. Gene overlaps are classically considered an obstacle for both evolution and genetic engineering, as mutations in overlapping regions likely have pleitrotropic effects on several genes. In 2013, we identified specific evolutionary scenarios where the decrease in evolutionary potential caused by gene overlaps could instead be advantageous and selected for. In this work, we demonstrate the use of gene overlaps in another context where reducing evolutionary potential can be useful: preventing evolution from inactivating synthetic circuits. We show that gene overlaps can be engineered to increase the evolutionary stability of genes that are costly to their hosts, by entangling these costly genes with essential genes.
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Affiliation(s)
| | - Antoine Frénoy
- Université de Paris, INSERM U1001, Paris, France
- Université Grenoble Alpes, CNRS UMR5525, Grenoble, France
- * E-mail: (AF); (ABL)
| | | | | | | | | | - Ariel B. Lindner
- Université de Paris, INSERM U1001, Paris, France
- Université de Paris, INSERM U1284, Center for Research and Interdisciplinarity (CRI), Paris, France
- * E-mail: (AF); (ABL)
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21
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Sutton G, Fogel GB, Abramson B, Brinkac L, Michael T, Liu ES, Thomas S. A pan-genome method to determine core regions of the Bacillus subtilis and Escherichia coli genomes. F1000Res 2021; 10:286. [PMID: 34113437 PMCID: PMC8156514 DOI: 10.12688/f1000research.51873.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/17/2021] [Indexed: 11/22/2022] Open
Abstract
Background: Synthetic engineering of bacteria to produce industrial products is a burgeoning field of research and application. In order to optimize genome design, designers need to understand which genes are essential, which are optimal for growth, and locations in the genome that will be tolerated by the organism when inserting engineered cassettes. Methods: We present a pan-genome based method for the identification of core regions in a genome that are strongly conserved at the species level. Results: We show that the core regions determined by our method contain all or almost all essential genes. This demonstrates the accuracy of our method as essential genes should be core genes. We show that we outperform previous methods by this measure. We also explain why there are exceptions to this rule for our method. Conclusions: We assert that synthetic engineers should avoid deleting or inserting into these core regions unless they understand and are manipulating the function of the genes in that region. Similarly, if the designer wishes to streamline the genome, non-core regions and in particular low penetrance genes would be good targets for deletion. Care should be taken to remove entire cassettes with similar penetrance of the genes within cassettes as they may harbor toxin/antitoxin genes which need to be removed in tandem. The bioinformatic approach introduced here saves considerable time and effort relative to knockout studies on single isolates of a given species and captures a broad understanding of the conservation of genes that are core to a species.
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Affiliation(s)
- Granger Sutton
- J. Craig Venter Institute, Rockville, Maryland, 20850, USA
| | - Gary B Fogel
- Natural Selection, Inc., San Diego, CA, 92121, USA
| | | | | | - Todd Michael
- J. Craig Venter Institute, Rockville, Maryland, 20850, USA
| | - Enoch S Liu
- Natural Selection, Inc., San Diego, CA, 92121, USA
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22
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23
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Rational engineering strategies for achieving high-yield, high-quality and high-stability of natural product production in actinomycetes. Metab Eng 2021; 67:198-215. [PMID: 34166765 DOI: 10.1016/j.ymben.2021.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/30/2021] [Accepted: 06/19/2021] [Indexed: 12/11/2022]
Abstract
Actinomycetes are recognized as excellent producers of microbial natural products, which have a wide range of applications, especially in medicine, agriculture and stockbreeding. The three main indexes of industrialization (titer, purity and stability) must be taken into overall consideration in the manufacturing process of natural products. Over the past decades, synthetic biology techniques have expedited the development of industrially competitive strains with excellent performances. Here, we summarize various rational engineering strategies for upgrading the performance of industrial actinomycetes, which include enhancing the yield of natural products, eliminating the by-products and improving the genetic stability of engineered strains. Furthermore, the current challenges and future perspectives for optimizing the industrial strains more systematically through combinatorial engineering strategies are also discussed.
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24
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Son HI, Weiss A, You L. Design patterns for engineering genetic stability. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2021; 19. [PMID: 34308010 DOI: 10.1016/j.cobme.2021.100297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The past 20 years have witnessed enormous progress in synthetic biology in the development of engineered cells for diverse applications, including biomanufacturing, materials fabrication, and potential therapeutics and diagnostics. However, it still remains a major challenge to maintain long-term performance of synthetic gene circuits, due to the emergence of mutants that lose circuit function. Here, we highlight major vulnerabilities of synthetic gene circuits resulting in circuit failure and mutant escape. We also discuss engineering strategies to enhance long-term circuit stability and performance. These approaches can be divided into two strategies: the suppression of the emergence of mutants and the suppression of their relative fitness if mutants do emerge. We anticipate that mechanistic understanding of the modes of circuit failure will facilitate future efforts to design evolutionarily robust synthetic biology-inspired applications.
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Affiliation(s)
- Hye-In Son
- Department of Biomedical Engineering, Duke University
| | - Andrea Weiss
- Department of Biomedical Engineering, Duke University
| | - Lingchong You
- Department of Biomedical Engineering, Duke University.,Center for Genomic and Computational Biology, Duke University.,Department of Molecular Genetics and Microbiology, Duke University School of Medicine
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25
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Castle SD, Grierson CS, Gorochowski TE. Towards an engineering theory of evolution. Nat Commun 2021; 12:3326. [PMID: 34099656 PMCID: PMC8185075 DOI: 10.1038/s41467-021-23573-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/04/2021] [Indexed: 02/07/2023] Open
Abstract
Biological technologies are fundamentally unlike any other because biology evolves. Bioengineering therefore requires novel design methodologies with evolution at their core. Knowledge about evolution is currently applied to the design of biosystems ad hoc. Unless we have an engineering theory of evolution, we will neither be able to meet evolution's potential as an engineering tool, nor understand or limit its unintended consequences for our biological designs. Here, we propose the evotype as a helpful concept for engineering the evolutionary potential of biosystems, or other self-adaptive technologies, potentially beyond the realm of biology.
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Affiliation(s)
- Simeon D Castle
- School of Biological Sciences, University of Bristol, Bristol, UK
| | - Claire S Grierson
- School of Biological Sciences, University of Bristol, Bristol, UK
- BrisSynBio, University of Bristol, Bristol, UK
| | - Thomas E Gorochowski
- School of Biological Sciences, University of Bristol, Bristol, UK.
- BrisSynBio, University of Bristol, Bristol, UK.
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26
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Sutton G, Fogel GB, Abramson B, Brinkac L, Michael T, Liu ES, Thomas S. A pan-genome method to determine core regions of the Bacillus subtilis and Escherichia coli genomes. F1000Res 2021; 10:286. [DOI: 10.12688/f1000research.51873.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/31/2021] [Indexed: 11/20/2022] Open
Abstract
Background: Synthetic engineering of bacteria to produce industrial products is a burgeoning field of research and application. In order to optimize genome design, designers need to understand which genes are essential, which are optimal for growth, and locations in the genome that will be tolerated by the organism when inserting engineered cassettes. Methods: We present a pan-genome based method for the identification of core regions in a genome that are strongly conserved at the species level. Results: We show that the core regions determined by our method contain all or almost all essential genes. This demonstrates the accuracy of our method as essential genes should be core genes. We show that we outperform previous methods by this measure. We also explain why there are exceptions to this rule for our method. Conclusions: We assert that synthetic engineers should avoid deleting or inserting into these core regions unless they understand and are manipulating the function of the genes in that region. Similarly, if the designer wishes to streamline the genome, non-core regions and in particular low penetrance genes would be good targets for deletion. Care should be taken to remove entire cassettes with similar penetrance of the genes within cassettes as they may harbor toxin/antitoxin genes which need to be removed in tandem. The bioinformatic approach introduced here saves considerable time and effort relative to knockout studies on single isolates of a given species and captures a broad understanding of the conservation of genes that are core to a species.
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27
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Ferenczi S, Solymosi N, Horváth I, Szeőcs N, Grózer Z, Kuti D, Juhász B, Winkler Z, Pankotai T, Sükösd F, Stágel A, Paholcsek M, Dóra D, Nagy N, Kovács KJ, Zanoni I, Szallasi Z. Efficient treatment of a preclinical inflammatory bowel disease model with engineered bacteria. Mol Ther Methods Clin Dev 2021; 20:218-226. [PMID: 33426148 PMCID: PMC7782194 DOI: 10.1016/j.omtm.2020.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 11/12/2020] [Indexed: 01/02/2023]
Abstract
We developed an orally administered, engineered, bacterium-based, RNA interference-mediated therapeutic method to significantly reduce the symptoms in the most frequently used animal model of inflammatory bowel disease. This bacterium-mediated RNA interference strategy was based on the genomically stable, non-pathogenic E. coli MDS42 strain, which was engineered to constitutively produce invasin and the listeriolysin O cytolysin. These proteins enabled the bacteria first to invade the colon epithelium and then degrade in the phagosome. This allowed the delivery of a plasmid encoding small hairpin RNA (shRNA) targeting tumor necrosis factor (TNF) into the cytoplasm of the target cells. The expression levels of TNF and other cytokines significantly decreased upon this treatment in dextran sulfate sodium (DSS)-induced colitis, and the degree of inflammation was significantly reduced. With further safety modifications this method could serve as a safe and side effect-free alternative to biologicals targeting TNF or other inflammatory mediators.
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Affiliation(s)
- Szilamer Ferenczi
- Institute of Experimental Medicine, Laboratory of Molecular Neuroendocrinology, Budapest, Hungary
- Central European Biosystems, Gödöllő, Hungary
| | - Norbert Solymosi
- Centre for Bioinformatics, University of Veterinary Medicine Budapest, Budapest, Hungary
| | | | | | | | - Dániel Kuti
- Institute of Experimental Medicine, Laboratory of Molecular Neuroendocrinology, Budapest, Hungary
| | - Balázs Juhász
- Institute of Experimental Medicine, Laboratory of Molecular Neuroendocrinology, Budapest, Hungary
| | - Zsuzsanna Winkler
- Institute of Experimental Medicine, Laboratory of Molecular Neuroendocrinology, Budapest, Hungary
| | - Tibor Pankotai
- Department of Biochemistry and Molecular Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Farkas Sükösd
- Department of Pathology, Laboratory of Molecular Pathology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Anikó Stágel
- Department of Human Genetics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Melinda Paholcsek
- Department of Human Genetics, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Dávid Dóra
- Department of Anatomy, Faculty of Medicine, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Nándor Nagy
- Department of Anatomy, Faculty of Medicine, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - Krisztina J. Kovács
- Institute of Experimental Medicine, Laboratory of Molecular Neuroendocrinology, Budapest, Hungary
| | - Ivan Zanoni
- Divisions of Immunology and Gastroenterology, Harvard Medical School, Boston Children’s Hospital, Boston, MA, USA
| | - Zoltan Szallasi
- Danish Cancer Society Research Center, Copenhagen, Denmark
- Computational Health Informatics Program, Boston Children’s Hospital, Boston, MA, USA
- 2nd Department of Pathology, MTA-SE NAP, Brain Metastasis Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
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Zhang C, Zheng W, Cheng M, Omenn GS, Freddolino PL, Zhang Y. Functions of Essential Genes and a Scale-Free Protein Interaction Network Revealed by Structure-Based Function and Interaction Prediction for a Minimal Genome. J Proteome Res 2021; 20:1178-1189. [PMID: 33393786 PMCID: PMC7867644 DOI: 10.1021/acs.jproteome.0c00359] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
When the JCVI-syn3.0 genome was designed and implemented in 2016 as the minimal genome of a free-living organism, approximately one-third of the 438 protein-coding genes had no known function. Subsequent refinement into JCVI-syn3A led to inclusion of 16 additional protein-coding genes, including several unknown functions, resulting in an improved growth phenotype. Here, we seek to unveil the biological roles and protein-protein interaction (PPI) networks for these poorly characterized proteins using state-of-the-art deep learning contact-assisted structure prediction, followed by structure-based annotation of functions and PPI predictions. Our pipeline is able to confidently assign functions for many previously unannotated proteins such as putative vitamin transporters, which suggest the importance of nutrient uptake even in a minimized genome. Remarkably, despite the artificial selection of genes in the minimal syn3 genome, our reconstructed PPI network still shows a power law distribution of node degrees typical of naturally evolved bacterial PPI networks. Making use of our framework for combined structure/function/interaction modeling, we are able to identify both fundamental aspects of network biology that are retained in a minimal proteome and additional essential functions not yet recognized among the poorly annotated components of the syn3.0 and syn3A proteomes.
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Affiliation(s)
- Chengxin Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Wei Zheng
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Micah Cheng
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Gilbert S Omenn
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Departments of Internal Medicine and Human Genetics and School of Public Health, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Peter L Freddolino
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yang Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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Fan X, Zhang Y, Zhao F, Liu Y, Zhao Y, Wang S, Liu R, Yang C. Genome reduction enhances production of polyhydroxyalkanoate and alginate oligosaccharide in Pseudomonas mendocina. Int J Biol Macromol 2020; 163:2023-2031. [DOI: 10.1016/j.ijbiomac.2020.09.067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/11/2020] [Accepted: 09/10/2020] [Indexed: 12/15/2022]
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Fan C, Davison PA, Habgood R, Zeng H, Decker CM, Gesell Salazar M, Lueangwattanapong K, Townley HE, Yang A, Thompson IP, Ye H, Cui Z, Schmidt F, Hunter CN, Huang WE. Chromosome-free bacterial cells are safe and programmable platforms for synthetic biology. Proc Natl Acad Sci U S A 2020; 117:6752-6761. [PMID: 32144140 PMCID: PMC7104398 DOI: 10.1073/pnas.1918859117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A type of chromosome-free cell called SimCells (simple cells) has been generated from Escherichia coli, Pseudomonas putida, and Ralstonia eutropha. The removal of the native chromosomes of these bacteria was achieved by double-stranded breaks made by heterologous I-CeuI endonuclease and the degradation activity of endogenous nucleases. We have shown that the cellular machinery remained functional in these chromosome-free SimCells and was able to process various genetic circuits. This includes the glycolysis pathway (composed of 10 genes) and inducible genetic circuits. It was found that the glycolysis pathway significantly extended longevity of SimCells due to its ability to regenerate ATP and NADH/NADPH. The SimCells were able to continuously express synthetic genetic circuits for 10 d after chromosome removal. As a proof of principle, we demonstrated that SimCells can be used as a safe agent (as they cannot replicate) for bacterial therapy. SimCells were used to synthesize catechol (a potent anticancer drug) from salicylic acid to inhibit lung, brain, and soft-tissue cancer cells. SimCells represent a simplified synthetic biology chassis that can be programmed to manufacture and deliver products safely without interference from the host genome.
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Affiliation(s)
- Catherine Fan
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Paul A Davison
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Robert Habgood
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Hong Zeng
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Christoph M Decker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany
| | - Manuela Gesell Salazar
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany
| | | | - Helen E Townley
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Aidong Yang
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Ian P Thompson
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Hua Ye
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Zhanfeng Cui
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom
| | - Frank Schmidt
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, 17475 Greifswald, Germany
- Proteomics Core, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Wei E Huang
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, United Kingdom;
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Liang P, Zhang Y, Xu B, Zhao Y, Liu X, Gao W, Ma T, Yang C, Wang S, Liu R. Deletion of genomic islands in the Pseudomonas putida KT2440 genome can create an optimal chassis for synthetic biology applications. Microb Cell Fact 2020; 19:70. [PMID: 32188438 PMCID: PMC7081699 DOI: 10.1186/s12934-020-01329-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 03/12/2020] [Indexed: 01/05/2023] Open
Abstract
Background Genome streamlining is a feasible strategy for constructing an optimum microbial chassis for synthetic biology applications. Genomic islands (GIs) are usually regarded as foreign DNA sequences, which can be obtained by horizontal gene transfer among microorganisms. A model strain Pseudomonas putida KT2440 has broad applications in biocatalysis, biotransformation and biodegradation. Results In this study, the identified GIs in P. putida KT2440 accounting for 4.12% of the total genome size were deleted to generate a series of genome-reduced strains. The mutant KTU-U13 with the largest deletion was advantageous over the original strain KTU in several physiological characteristics evaluated. The mutant KTU-U13 showed high plasmid transformation efficiency and heterologous protein expression capacity compared with the original strain KTU. The metabolic phenotype analysis showed that the types of carbon sources utilized by the mutant KTU-U13 and the utilization capabilities for certain carbon sources were increased greatly. The polyhydroxyalkanoate (PHA) yield and cell dry weight of the mutant KTU-U13 were improved significantly compared with the original strain KTU. The chromosomal integration efficiencies for the γ-hexachlorocyclohexane (γ-HCH) and 1,2,3-trichloropropane (TCP) biodegradation pathways were improved greatly when using the mutant KTU-U13 as the recipient cell and enhanced degradation of γ-HCH and TCP by the mutant KTU-U13 was also observed. The mutant KTU-U13 was able to stably express a plasmid-borne zeaxanthin biosynthetic pathway, suggesting the excellent genetic stability of the mutant. Conclusions These desirable traits make the GIs-deleted mutant KTU-U13 an optimum chassis for synthetic biology applications. The present study suggests that the systematic deletion of GIs in bacteria may be a useful approach for generating an optimal chassis for the construction of microbial cell factories.
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Affiliation(s)
- Peixin Liang
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Yiting Zhang
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Bo Xu
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Yuxin Zhao
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Xiangsheng Liu
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Weixia Gao
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Ting Ma
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China
| | - Chao Yang
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, Nankai University, Tianjin, 300071, China.
| | - Shufang Wang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China.
| | - Ruihua Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China.
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Calles B, Goñi‐Moreno Á, de Lorenzo V. Digitalizing heterologous gene expression in Gram-negative bacteria with a portable ON/OFF module. Mol Syst Biol 2019; 15:e8777. [PMID: 31885200 PMCID: PMC6920698 DOI: 10.15252/msb.20188777] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 10/16/2019] [Accepted: 10/24/2019] [Indexed: 01/24/2023] Open
Abstract
While prokaryotic promoters controlled by signal-responding regulators typically display a range of input/output ratios when exposed to cognate inducers, virtually no naturally occurring cases are known to have an OFF state of zero transcription-as ideally needed for synthetic circuits. To overcome this problem, we have modelled and implemented a simple digitalizer module that completely suppresses the basal level of otherwise strong promoters in such a way that expression in the absence of induction is entirely impeded. The circuit involves the interplay of a translation-inhibitory sRNA with the translational coupling of the gene of interest to a repressor such as LacI. The digitalizer module was validated with the strong inducible promoters Pm (induced by XylS in the presence of benzoate) and PalkB (induced by AlkS/dicyclopropyl ketone) and shown to perform effectively in both Escherichia coli and the soil bacterium Pseudomonas putida. The distinct expression architecture allowed cloning and conditional expression of, e.g. colicin E3, one molecule of which per cell suffices to kill the host bacterium. Revertants that escaped ColE3 killing were not found in hosts devoid of insertion sequences, suggesting that mobile elements are a major source of circuit inactivation in vivo.
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Affiliation(s)
- Belén Calles
- Systems Biology ProgramCentro Nacional de Biotecnología‐CSICMadridSpain
| | - Ángel Goñi‐Moreno
- Systems Biology ProgramCentro Nacional de Biotecnología‐CSICMadridSpain
- Present address:
School of ComputingNewcastle UniversityNewcastle upon TyneUK
| | - Víctor de Lorenzo
- Systems Biology ProgramCentro Nacional de Biotecnología‐CSICMadridSpain
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Wynands B, Otto M, Runge N, Preckel S, Polen T, Blank LM, Wierckx N. Streamlined Pseudomonas taiwanensis VLB120 Chassis Strains with Improved Bioprocess Features. ACS Synth Biol 2019; 8:2036-2050. [PMID: 31465206 DOI: 10.1021/acssynbio.9b00108] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Microbes harbor many traits that are dispensable or even unfavorable under industrial and laboratory settings. The elimination of such traits could improve the host's efficiency, genetic stability, and robustness, thereby increasing the predictability and boosting its performance as a microbial cell factory. We engineered solvent-tolerant Pseudomonas taiwanensis VLB120 to yield streamlined chassis strains with higher growth rates and biomass yields, enhanced solvent tolerance, and improved process performance. In total, the genome was reduced by up to 10%. This was achieved by the elimination of genes that enable the cell to swim and form biofilms and by the deletion of the megaplasmid pSTY and large proviral segments. The resulting strain GRC1 had a 15% higher growth rate and biomass yield than the wildtype. However, this strain lacks the pSTY-encoded efflux pump TtgGHI, rendering it solvent-sensitive. Through reintegration of ttgGHI by chromosomal insertion without (GRC2) and with (GRC3) the corresponding regulator genes, the solvent-tolerant phenotype was enhanced. The generated P. taiwanensis GRC strains enlarge the repertoire of streamlined chassis with enhanced key performance indicators, making them attractive hosts for biotechnological applications. The different solvent tolerance levels of GRC1, GRC2, and GRC3 enable the selection of a fitting host platform in relation to the desired process requirements in a chassis à la carte principle. This was demonstrated in a metabolic engineering approach for the production of phenol from glycerol. The streamlined producer GRC1Δ5-TPL38 outperformed the equivalent nonstreamlined producer VLB120Δ5-TPL38 concerning phenol titer, rate, and yield, thereby highlighting the added value of the streamlined chassis.
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Affiliation(s)
- Benedikt Wynands
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Maike Otto
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Nadine Runge
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Sarah Preckel
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Tino Polen
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Lars M. Blank
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Nick Wierckx
- Institute of Applied Microbiology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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Fernández‐Cabezón L, Cros A, Nikel PI. Evolutionary Approaches for Engineering Industrially Relevant Phenotypes in Bacterial Cell Factories. Biotechnol J 2019; 14:e1800439. [DOI: 10.1002/biot.201800439] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/08/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Lorena Fernández‐Cabezón
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark 2800 Kongens Lyngby Denmark
| | - Antonin Cros
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark 2800 Kongens Lyngby Denmark
| | - Pablo I. Nikel
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of Denmark 2800 Kongens Lyngby Denmark
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Kelpšas V, Lafumat B, Blakeley MP, Coquelle N, Oksanen E, von Wachenfeldt C. Perdeuteration, large crystal growth and neutron data collection of Leishmania mexicana triose-phosphate isomerase E65Q variant. Acta Crystallogr F Struct Biol Commun 2019; 75:260-269. [PMID: 30950827 PMCID: PMC6450519 DOI: 10.1107/s2053230x19001882] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/31/2019] [Indexed: 01/07/2023] Open
Abstract
Triose-phosphate isomerase (TIM) catalyses the interconversion of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. Two catalytic mechanisms have been proposed based on two reaction-intermediate analogues, 2-phosphoglycolate (2PG) and phosphoglycolohydroxamate (PGH), that have been used as mimics of the cis-enediol(ate) intermediate in several studies of TIM. The protonation states that are critical for the mechanistic interpretation of these structures are generally not visible in the X-ray structures. To resolve these questions, it is necessary to determine the hydrogen positions using neutron crystallography. Neutron crystallography requires large crystals and benefits from replacing all hydrogens with deuterium. Leishmania mexicana triose-phosphate isomerase was therefore perdeuterated and large crystals with 2PG and PGH were produced. Neutron diffraction data collected from two crystals with different volumes highlighted the importance of crystal volume, as smaller crystals required longer exposures and resulted in overall worse statistics.
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Affiliation(s)
- Vinardas Kelpšas
- Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
| | - Bénédicte Lafumat
- Department of Biology, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
- European Spallation Source ESS ERIC, Odarslövsvägen 113, 224 84 Lund, Sweden
| | | | - Nicolas Coquelle
- Insitut Laue–Langevin, 71 Avenue des Martyrs, 38042 Grenoble, France
| | - Esko Oksanen
- European Spallation Source ESS ERIC, Odarslövsvägen 113, 224 84 Lund, Sweden
- Department of Biochemistry and Structural Biology, Lund University, Sölvegatan 39A, 221 00 Lund, Sweden
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Geng P, Leonard SP, Mishler DM, Barrick JE. Synthetic Genome Defenses against Selfish DNA Elements Stabilize Engineered Bacteria against Evolutionary Failure. ACS Synth Biol 2019; 8:521-531. [PMID: 30703321 DOI: 10.1021/acssynbio.8b00426] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Mobile genetic elements drive evolution by disrupting genes and rearranging genomes. Eukaryotes have evolved epigenetic mechanisms, including DNA methylation and RNA interference, that silence mobile elements and thereby preserve the integrity of their genomes. We created an artificial reprogrammable epigenetic system based on CRISPR interference to give engineered bacteria a similar line of defense against transposons and other selfish elements in their genomes. We demonstrate that this CRISPR interference against mobile elements (CRISPRi-ME) approach can be used to simultaneously repress two different transposon families in Escherichia coli, thereby increasing the evolutionary stability of costly protein expression. We further show that silencing a transposon in Acinetobacter baylyi ADP1 reduces mutation rates by a factor of 5, nearly as much as deleting all copies of this element from its genome. By deploying CRISPRi-ME on a broad-host-range vector, we have created a generalizable platform for stabilizing the genomes of engineered bacterial cells for applications in metabolic engineering and synthetic biology.
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Affiliation(s)
- Peng Geng
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Sean P. Leonard
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Dennis M. Mishler
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jeffrey E. Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, United States
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Chi H, Wang X, Shao Y, Qin Y, Deng Z, Wang L, Chen S. Engineering and modification of microbial chassis for systems and synthetic biology. Synth Syst Biotechnol 2019; 4:25-33. [PMID: 30560208 PMCID: PMC6290258 DOI: 10.1016/j.synbio.2018.12.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/14/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022] Open
Abstract
Engineering and modifying synthetic microbial chassis is one of the best ways not only to unravel the fundamental principles of life but also to enhance applications in the health, medicine, agricultural, veterinary, and food industries. The two primary strategies for constructing a microbial chassis are the top-down approach (genome reduction) and the bottom-up approach (genome synthesis). Research programs on this topic have been funded in several countries. The 'Minimum genome factory' (MGF) project was launched in 2001 in Japan with the goal of constructing microorganisms with smaller genomes for industrial use. One of the best examples of the results of this project is E. coli MGF-01, which has a reduced-genome size and exhibits better growth and higher threonine production characteristics than the parental strain [1]. The 'cell factory' project was carried out from 1998 to 2002 in the Fifth Framework Program of the EU (European Union), which tried to comprehensively understand microorganisms used in the application field. One of the outstanding results of this project was the elucidation of proteins secreted by Bacillus subtilis, which was summarized as the 'secretome' [2]. The GTL (Genomes to Life) program began in 2002 in the United States. In this program, researchers aimed to create artificial cells both in silico and in vitro, such as the successful design and synthesis of a minimal bacterial genome by John Craig Venter's group [3]. This review provides an update on recent advances in engineering, modification and application of synthetic microbial chassis, with particular emphasis on the value of learning about chassis as a way to better understand life and improve applications.
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Affiliation(s)
- Haotian Chi
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
- Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, China
| | - Xiaoli Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Yue Shao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Ying Qin
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Lianrong Wang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
| | - Shi Chen
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Zhongnan Hospital, Wuhan University, Wuhan, 430071, China
- Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, China
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Nikel PI, de Lorenzo V. Pseudomonas putida as a functional chassis for industrial biocatalysis: From native biochemistry to trans-metabolism. Metab Eng 2018; 50:142-155. [DOI: 10.1016/j.ymben.2018.05.005] [Citation(s) in RCA: 245] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 12/12/2022]
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Deatherage DE, Leon D, Rodriguez ÁE, Omar SK, Barrick JE. Directed evolution of Escherichia coli with lower-than-natural plasmid mutation rates. Nucleic Acids Res 2018; 46:9236-9250. [PMID: 30137492 PMCID: PMC6158703 DOI: 10.1093/nar/gky751] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/03/2018] [Accepted: 08/08/2018] [Indexed: 12/24/2022] Open
Abstract
Unwanted evolution of designed DNA sequences limits metabolic and genome engineering efforts. Engineered functions that are burdensome to host cells and slow their replication are rapidly inactivated by mutations, and unplanned mutations with unpredictable effects often accumulate alongside designed changes in large-scale genome editing projects. We developed a directed evolution strategy, Periodic Reselection for Evolutionarily Reliable Variants (PResERV), to discover mutations that prolong the function of a burdensome DNA sequence in an engineered organism. Here, we used PResERV to isolate Escherichia coli cells that replicate ColE1-type plasmids with higher fidelity. We found mutations in DNA polymerase I and in RNase E that reduce plasmid mutation rates by 6- to 30-fold. The PResERV method implicitly selects to maintain the growth rate of host cells, and high plasmid copy numbers and gene expression levels are maintained in some of the evolved E. coli strains, indicating that it is possible to improve the genetic stability of cellular chassis without encountering trade-offs in other desirable performance characteristics. Utilizing these new antimutator E. coli and applying PResERV to other organisms in the future promises to prevent evolutionary failures and unpredictability to provide a more stable genetic foundation for synthetic biology.
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Affiliation(s)
- Daniel E Deatherage
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Dacia Leon
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Álvaro E Rodriguez
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Salma K Omar
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
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de Lorenzo V. Evolutionary tinkering vs. rational engineering in the times of synthetic biology. LIFE SCIENCES, SOCIETY AND POLICY 2018; 14:18. [PMID: 30099657 PMCID: PMC6087506 DOI: 10.1186/s40504-018-0086-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Synthetic biology is not only a contemporary reformulation of the recombinant DNA technologies of the last 30 years, combined with descriptive language imported from electrical and industrial engineering. It is also a new way to interpret living systems and a statement of intent for the use and reprogramming of biological objects for human benefit. In this context, the notion of designer biology is often presented as opposed to natural selection following the powerful rationale formulated by François Jacob on evolution-as-tinkering. The onset of synthetic biology opens a different perspective by leaving aside the question about the evolutionary origin of biological phenomena and focusing instead on the relational logic and the material properties of the corresponding components that make biological system work as they do. Once a functional challenge arises, the solution space for the problem is not homogeneous but it has attractors that can be accessed either through random exploration (as evolution does) or rational design (as engineers do). Although these two paths (i.e. evolution and engineering) are essentially different, they can lead to solutions to specific mechanistic bottlenecks that frequently coincide or converge-and one can easily help to understand and improve the other. Alas, productive discussions on these matters are often contaminated by ideological preconceptions that prevent adoption of the engineering metaphor to understand and ultimately reshape living systems-as ambitioned by synthetic biology. Yet, some possible ways to overcome the impasse are feasible. In parallel to Monod's evolutionary paradox of teleo-logy (finality/purpose) vs. teleo-nomy (appearance of finality/purpose), a mechanistic paradox could be entertained between techno-logy (rational engineering) vs techno-nomy (appearance of rational engineering), all for the sake of understanding the relational logic that enables live systems to function as physico-chemical entities in time and space. This article thus proposes a radical vision of synthetic biology through the lens of the engineering metaphor.
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Affiliation(s)
- Víctor de Lorenzo
- Centro Nacional de Biotecnología-CSIC, Campus de Cantoblanco, 28049, Madrid, Spain.
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Balikó G, Vernyik V, Karcagi I, Györfy Z, Draskovits G, Fehér T, Pósfai G. Rational Efforts to Streamline the Escherichia coliGenome. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Gabriella Balikó
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Viktor Vernyik
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Ildikó Karcagi
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Zsuzsanna Györfy
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Gábor Draskovits
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Tamás Fehér
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - György Pósfai
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
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Couto JM, McGarrity A, Russell J, Sloan WT. The effect of metabolic stress on genome stability of a synthetic biology chassis Escherichia coli K12 strain. Microb Cell Fact 2018; 17:8. [PMID: 29357936 PMCID: PMC5776760 DOI: 10.1186/s12934-018-0858-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 01/15/2018] [Indexed: 12/14/2022] Open
Abstract
Background Synthetic organism-based biotechnologies are increasingly being proposed for environmental applications, such as in situ sensing. Typically, the novel function of these organisms is delivered by compiling genetic fragments in the genome of a chassis organism. To behave predictably, these chassis are designed with reduced genomes that minimize biological complexity. However, in these proposed applications it is expected that even when contained within a device, organisms will be exposed to fluctuating, often stressful, conditions and it is not clear whether their genomes will retain stability. Results Here we employed a chemostat design which enabled us to maintained two strains of E. coli K12 under sustained starvation stress: first the reduced genome synthetic biology chassis MDS42 and then, the control parent strain MG1655. We estimated mutation rates and utilised them as indicators of an increase in genome instability. We show that within 24 h the spontaneous mutation rate had increased similarly in both strains, destabilizing the genomes. High rates were maintained for the duration of the experiment. Growth rates of a cohort of randomly sampled mutants from both strains were utilized as a proxy for emerging phenotypic, and by association genetic variation. Mutant growth rates were consistently less than rates in non-mutants, an indicator of reduced fitness and the presence of mildly deleterious mutations in both the strains. In addition, the effect of these mutations on the populations as a whole varied by strain. Conclusions Overall, this study shows that genome reductions in the MDS42 did not stabilize the chassis under metabolic stress. Over time, this could compromise the effectiveness of synthetic organisms built on chassis in environmental applications. Electronic supplementary material The online version of this article (10.1186/s12934-018-0858-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jillian M Couto
- Division of Infrastructure and Environment, School of Engineering, University of Glasgow, Rankine Building, Level 5, Glasgow, G12 8QQ, UK.
| | - Anne McGarrity
- Division of Infrastructure and Environment, School of Engineering, University of Glasgow, Rankine Building, Level 5, Glasgow, G12 8QQ, UK
| | - Julie Russell
- Division of Infrastructure and Environment, School of Engineering, University of Glasgow, Rankine Building, Level 5, Glasgow, G12 8QQ, UK
| | - William T Sloan
- Division of Infrastructure and Environment, School of Engineering, University of Glasgow, Rankine Building, Level 5, Glasgow, G12 8QQ, UK
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Kambouris ME, Manoussopoulos Y, Kantzanou M, Velegraki A, Gaitanis G, Arabatzis M, Patrinos GP. Rebooting Bioresilience: A Multi-OMICS Approach to Tackle Global Catastrophic Biological Risks and Next-Generation Biothreats. ACTA ACUST UNITED AC 2018; 22:35-51. [DOI: 10.1089/omi.2017.0185] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Manousos E. Kambouris
- Department of Pharmacy, University of Patras, Rio Patras, Greece
- Department of Food Technology, ATEI of Thessaly, Karditsa, Greece
| | - Yiannis Manoussopoulos
- Plant Protection Division of Patras, Institute of Industrial and Forage Plants, Patras, Greece
| | - Maria Kantzanou
- Department of Hygiene, Epidemiology and Medical Statistics, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Aristea Velegraki
- Department of Microbiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Gaitanis
- Department of Skin and Venereal Diseases, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece
| | - Michalis Arabatzis
- First Department of Dermatology, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
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44
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Du W, Burbano PC, Hellingwerf KJ, Branco Dos Santos F. Challenges in the Application of Synthetic Biology Toward Synthesis of Commodity Products by Cyanobacteria via "Direct Conversion". ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:3-26. [PMID: 30091089 DOI: 10.1007/978-981-13-0854-3_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cyanobacterial direct conversion of CO2 to several commodity chemicals has been recognized as a potential contributor to support the much-needed sustainable development of human societies. However, the feasibility of this "green conversion" hinders on our ability to overcome the hurdles presented by the natural evolvability of microbes. The latter may result in the genetic instability of engineered cyanobacterial strains leading to impaired productivity. This challenge is general to any "cell factory" approach in which the cells grow for multiple generations, and based on several studies carried out in different microbial hosts, we could identify that three distinct strategies have been proposed to tackle it. These are (1) to reduce microbial evolvability by decreasing the native mutation rate, (2) to align product formation with cell growth/fitness, and, paradoxically, (3) to efficiently reallocate cellular resources to product formation by uncoupling it from growth. The implementation of either of these strategies requires an advanced synthetic biology toolkit. Here, we review the existing methods available for cyanobacteria and identify areas of focus in which specific developments are still needed. Furthermore, we discuss how potentially stabilizing strategies may be used in combination leading to further increases of productivity while ensuring the stability of the cyanobacterial-based direct conversion process.
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Affiliation(s)
- Wei Du
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Patricia Caicedo Burbano
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Klaas J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Filipe Branco Dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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Yuan X, Couto JM, Glidle A, Song Y, Sloan W, Yin H. Single-Cell Microfluidics to Study the Effects of Genome Deletion on Bacterial Growth Behavior. ACS Synth Biol 2017; 6:2219-2227. [PMID: 28844132 DOI: 10.1021/acssynbio.7b00177] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
By directly monitoring single cell growth in a microfluidic platform, we interrogated genome-deletion effects in Escherichia coli strains. We compared the growth dynamics of a wild type strain with a clean genome strain, and their derived mutants at the single-cell level. A decreased average growth rate and extended average lag time were found for the clean genome strain, compared to those of the wild type strain. Direct correlation between the growth rate and lag time of individual cells showed that the clean genome population was more heterogeneous. Cell culturability (the ratio of growing cells to the sum of growing and nongrowing cells) of the clean genome population was also lower. Interestingly, after the random mutations induced by a glucose starvation treatment, for the clean genome population mutants that had survived the competition of chemostat culture, each parameter markedly improved (i.e., the average growth rate and cell culturability increased, and the lag time and heterogeneity decreased). However, this effect was not seen in the wild type strain; the wild type mutants cultured in a chemostat retained a high diversity of growth phenotypes. These results suggest that quasi-essential genes that were deleted in the clean genome might be required to retain a diversity of growth characteristics at the individual cell level under environmental stress. These observations highlight that single-cell microfluidics can reveal subtle individual cellular responses, enabling in-depth understanding of the population.
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Affiliation(s)
- Xiaofei Yuan
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Jillian M. Couto
- College
of Science and Engineering, Division of Infrastructure and Environment,
School of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Andrew Glidle
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Yanqing Song
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - William Sloan
- College
of Science and Engineering, Division of Infrastructure and Environment,
School of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
| | - Huabing Yin
- College
of Science and Engineering, Division of Biomedical Engineering, School
of Engineering, University of Glasgow, Glasgow G12 8QQ, U.K
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Umenhoffer K, Draskovits G, Nyerges Á, Karcagi I, Bogos B, Tímár E, Csörgő B, Herczeg R, Nagy I, Fehér T, Pál C, Pósfai G. Genome-Wide Abolishment of Mobile Genetic Elements Using Genome Shuffling and CRISPR/Cas-Assisted MAGE Allows the Efficient Stabilization of a Bacterial Chassis. ACS Synth Biol 2017; 6:1471-1483. [PMID: 28426191 DOI: 10.1021/acssynbio.6b00378] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The ideal bacterial chassis provides a simplified, stable and predictable host environment for synthetic biological circuits. Mutability and evolution can, however, compromise stability, leading to deterioration of artificial genetic constructs. By eliminating certain sources of instability, these undesired genetic changes can be mitigated. Specifically, deletion of prophages and insertion sequences, nonessential constituents of bacterial genomes, has been shown to be beneficial in cellular and genetic stabilization. Here, we sought to establish a rapid methodology to improve the stability of microbial hosts. The novel workflow involves genome shuffling between a mobile genetic element-free strain and the target cell, and subsequent rounds of CRISPR/Cas-assisted MAGE on multiplex targets. The power and speed of the procedure was demonstrated on E. coli BL21(DE3), a host routinely used for plasmid-based heterologous protein expression. All 9 prophages and 50 insertion elements were efficiently deleted or inactivated. Together with additional targeted manipulations (e.g., inactivation of error-prone DNA-polymerases), the changes resulted in an improved bacterial host with a hybrid (harboring segments of K-12 DNA), 9%-downsized and clean genome. The combined capacity of phage-mediated generalized transduction and CRISPR/Cas-selected MAGE offers a way for rapid, large scale editing of bacterial genomes.
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Affiliation(s)
- Kinga Umenhoffer
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Gábor Draskovits
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Ákos Nyerges
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Ildikó Karcagi
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Balázs Bogos
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Edit Tímár
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Bálint Csörgő
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | | | - István Nagy
- SeqOmics Biotechnology Ltd, 6782 Mórahalom, Hungary
- Institute
of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Tamás Fehér
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - Csaba Pál
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
| | - György Pósfai
- Synthetic
and Systems Biology Unit, Institute of Biochemistry, Biological Research Centre of the Hungarian Academy of Sciences, 6726 Szeged, Hungary
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Reduced Mutation Rate and Increased Transformability of Transposon-Free Acinetobacter baylyi ADP1-ISx. Appl Environ Microbiol 2017; 83:AEM.01025-17. [PMID: 28667117 DOI: 10.1128/aem.01025-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 06/21/2017] [Indexed: 01/02/2023] Open
Abstract
The genomes of most bacteria contain mobile DNA elements that can contribute to undesirable genetic instability in engineered cells. In particular, transposable insertion sequence (IS) elements can rapidly inactivate genes that are important for a designed function. We deleted all six copies of IS1236 from the genome of the naturally transformable bacterium Acinetobacter baylyi ADP1. The natural competence of ADP1 made it possible to rapidly repair deleterious point mutations that arose during strain construction. In the resulting ADP1-ISx strain, the rates of mutations inactivating a reporter gene were reduced by 7- to 21-fold. This reduction was higher than expected from the incidence of new IS1236 insertions found during a 300-day mutation accumulation experiment with wild-type ADP1 that was used to estimate spontaneous mutation rates in the strain. The extra improvement appears to be due in part to eliminating large deletions caused by IS1236 activity, as the point mutation rate was unchanged in ADP1-ISx. Deletion of an error-prone polymerase (dinP) and a DNA damage response regulator (umuDAb [the umuD gene of A. baylyi]) from the ADP1-ISx genome did not further reduce mutation rates. Surprisingly, ADP1-ISx exhibited increased transformability. This improvement may be due to less autolysis and aggregation of the engineered cells than of the wild type. Thus, deleting IS elements from the ADP1 genome led to a greater than expected increase in evolutionary reliability and unexpectedly enhanced other key strain properties, as has been observed for other clean-genome bacterial strains. ADP1-ISx is an improved chassis for metabolic engineering and other applications.IMPORTANCEAcinetobacter baylyi ADP1 has been proposed as a next-generation bacterial host for synthetic biology and genome engineering due to its ability to efficiently take up DNA from its environment during normal growth. We deleted transposable elements that are capable of copying themselves, inserting into other genes, and thereby inactivating them from the ADP1 genome. The resulting "clean-genome" ADP1-ISx strain exhibited larger reductions in the rates of inactivating mutations than expected from spontaneous mutation rates measured via whole-genome sequencing of lineages evolved under relaxed selection. Surprisingly, we also found that IS element activity reduces transformability and is a major cause of cell aggregation and death in wild-type ADP1 grown under normal laboratory conditions. More generally, our results demonstrate that domesticating a bacterial genome by removing mobile DNA elements that have accumulated during evolution in the wild can have unanticipated benefits.
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Moses T, Mehrshahi P, Smith AG, Goossens A. Synthetic biology approaches for the production of plant metabolites in unicellular organisms. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4057-4074. [PMID: 28449101 DOI: 10.1093/jxb/erx119] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Synthetic biology is the repurposing of biological systems for novel objectives and applications. Through the co-ordinated and balanced expression of genes, both native and those introduced from other organisms, resources within an industrial chassis can be siphoned for the commercial production of high-value commodities. This developing interdisciplinary field has the potential to revolutionize natural product discovery from higher plants, by providing a diverse array of tools, technologies, and strategies for exploring the large chemically complex space of plant natural products using unicellular organisms. In this review, we emphasize the key features that influence the generation of biorefineries and highlight technologies and strategic solutions that can be used to overcome engineering pitfalls with rational design. Also presented is a succinct guide to assist the selection of unicellular chassis most suited for the engineering and subsequent production of the desired natural product, in order to meet the global demand for plant natural products in a safe and sustainable manner.
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Affiliation(s)
- Tessa Moses
- Ghent University, Department of Plant Biotechnology and Bioinformatics, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
| | - Payam Mehrshahi
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Alain Goossens
- Ghent University, Department of Plant Biotechnology and Bioinformatics, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, 9052 Ghent, Belgium
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Abstract
Genome size is determined during evolution, but it can also be altered by genetic engineering in laboratories. The systematic characterization of reduced genomes provides valuable insights into the cellular properties that are quantitatively described by the global parameters related to the dynamics of growth and mutation. In the present study, we analyzed a small collection of W3110 Escherichia coli derivatives containing either the wild-type genome or reduced genomes of various lengths to examine whether the mutation rate, a global parameter representing genomic plasticity, was affected by genome reduction. We found that the mutation rates of these cells increased with genome reduction. The correlation between genome length and mutation rate, which has been reported for the evolution of bacteria, was also identified, intriguingly, for genome reduction. Gene function enrichment analysis indicated that the deletion of many of the genes encoding membrane and transport proteins play a role in the mutation rate changes mediated by genome reduction. Furthermore, the increase in the mutation rate with genome reduction was highly associated with a decrease in the growth rate in a nutrition-dependent manner; thus, poorer media showed a larger change that was of higher significance. This negative correlation was strongly supported by experimental evidence that the serial transfer of the reduced genome improved the growth rate and reduced the mutation rate to a large extent. Taken together, the global parameters corresponding to the genome, growth, and mutation showed a coordinated relationship, which might be an essential working principle for balancing the cellular dynamics appropriate to the environment. Genome reduction is a powerful approach for investigating the fundamental rules for living systems. Whether genetically disturbed genomes have any specific properties that are different from or similar to those of natively evolved genomes has been under investigation. In the present study, we found that Escherichia coli cells with reduced genomes showed accelerated nucleotide substitution errors (mutation rates), although these cells retained the normal DNA mismatch repair systems. Intriguingly, this finding of correlation between reduced genome size and a higher mutation rate was consistent with the reported evolution of mutation rates. Furthermore, the increased mutation rate was quantitatively associated with a decreased growth rate, indicating that the global parameters related to the genome, growth, and mutation, which represent the amount of genetic information, the efficiency of propagation, and the fidelity of replication, respectively, are dynamically coordinated.
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50
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Bursac T, Gralnick JA, Gescher J. Acetoin production via unbalanced fermentation in Shewanella oneidensis. Biotechnol Bioeng 2017; 114:1283-1289. [DOI: 10.1002/bit.26243] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/27/2016] [Accepted: 01/03/2017] [Indexed: 12/17/2022]
Affiliation(s)
- Thea Bursac
- Department of Applied Biology; Institute for Applied Biosciences; Karlsruhe Institute of Technology; Karlsruhe Germany
| | - Jeffrey A. Gralnick
- BioTechnology Institute and Department of Microbiology; University of Minnesota; Twin Cities St. Paul, Minnesota
| | - Johannes Gescher
- Department of Applied Biology; Institute for Applied Biosciences; Karlsruhe Institute of Technology; Karlsruhe Germany
- Department of Microbiology of Natural and Technical Interfaces; Institute of Functional Interfaces; Karlsruhe Institute of Technology; Eggenstein-Leopoldshafen Germany
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