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Piorino F, Styczynski MP. Complex Dependence of Escherichia coli-based Cell-Free Expression on Sonication Energy During Lysis. ACS Synth Biol 2023; 12:3131-3136. [PMID: 37725792 PMCID: PMC10594866 DOI: 10.1021/acssynbio.3c00312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Indexed: 09/21/2023]
Abstract
Cell lysis─by sonication or bead beating, for example─is a key step in preparing extracts for cell-free expression systems. To create high protein-production capacity extracts, standard practice is to lyse cells sufficiently to thoroughly disrupt the membrane and thus extract expression machinery but without degrading that machinery. Here, we investigate the impact of different sonication energy inputs on the protein-production capacity of Escherichia coli extracts. While the existence of operator-specific optimal sonication energy inputs is widely known, our findings show that the sonication energy input that yields maximal protein output from a given expression template may depend on plasmid concentration, transcriptional and translational features (e.g., promoter), and other expression vector components (e.g., origin of replication). These results indicate that sonication protocols cannot be standardized to a single optimum, suggest strategies for improving protein yields, and more broadly highlight the need for better metrics and protocols for characterizing cell extracts.
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Affiliation(s)
- Fernanda Piorino
- School of Chemical & Biomolecular
Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, United States
| | - Mark P. Styczynski
- School of Chemical & Biomolecular
Engineering, Georgia Institute of Technology, 311 Ferst Drive NW, Atlanta, Georgia 30332-0100, United States
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2
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Abstract
Phage therapy to treat life-threatening drug-resistant infections has been hampered by technical challenges in phage production. Cell-free bacteriophage synthesis (CFBS) can overcome the limitations of standard phage production methods by manufacturing phage virions in vitro. CFBS mimics intracellular phage assembly using transcription/translation machinery (TXTL) harvested from bacterial lysates and combined with reagents to synthesize proteins encoded by a phage genomic DNA template. These systems may enable rapid phage production and engineering to accelerate phages from bench-to-bedside. TXTL harvested from wild type or commonly used bacterial strains was not optimized for bacteriophage production. Here, we demonstrate that TXTL from genetically modified E. coli BL21 can be used to enhance phage T7 yields in vitro by CFBS. Expression of 18 E. coli BL21 genes was manipulated by inducible CRISPR interference (CRISPRi) mediated by nuclease deficient Cas12a from F. novicida (dFnCas12a) to identify genes implicated in T7 propagation as positive or negative effectors. Genes shown to have a significant effect were overexpressed (positive effectors) or repressed (negative effectors) to modify the genetic background of TXTL harvested for CFBS. Phage T7 CFBS yields were improved by up to 10-fold in vitro through overexpression of translation initiation factor IF-3 (infC) and small RNAs OxyS and CyaR and by repression of RecC subunit exonuclease RecBCD. Continued improvement of CFBS will mitigate phage manufacturing bottlenecks and lower hurdles to widespread adoption of phage therapy.
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Affiliation(s)
- Rani Brooks
- Interdisciplinary
Bioinnovation PhD Program, Tulane University, New Orleans, Louisiana 70118-5665, United
States
| | - Lisa Morici
- Department
of Microbiology and Immunology, Tulane University
School of Medicine, New Orleans, Louisiana 70112, United States
| | - Nicholas Sandoval
- Department
of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana 70118, United States
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3
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Brookwell A, Oza JP, Caschera F. Biotechnology Applications of Cell-Free Expression Systems. Life (Basel) 2021; 11:life11121367. [PMID: 34947898 PMCID: PMC8705439 DOI: 10.3390/life11121367] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/13/2022] Open
Abstract
Cell-free systems are a rapidly expanding platform technology with an important role in the engineering of biological systems. The key advantages that drive their broad adoption are increased efficiency, versatility, and low cost compared to in vivo systems. Traditionally, in vivo platforms have been used to synthesize novel and industrially relevant proteins and serve as a testbed for prototyping numerous biotechnologies such as genetic circuits and biosensors. Although in vivo platforms currently have many applications within biotechnology, they are hindered by time-constraining growth cycles, homeostatic considerations, and limited adaptability in production. Conversely, cell-free platforms are not hindered by constraints for supporting life and are therefore highly adaptable to a broad range of production and testing schemes. The advantages of cell-free platforms are being leveraged more commonly by the biotechnology community, and cell-free applications are expected to grow exponentially in the next decade. In this study, new and emerging applications of cell-free platforms, with a specific focus on cell-free protein synthesis (CFPS), will be examined. The current and near-future role of CFPS within metabolic engineering, prototyping, and biomanufacturing will be investigated as well as how the integration of machine learning is beneficial to these applications.
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Affiliation(s)
- August Brookwell
- Department of Chemistry & Biochemistry, College of Science & Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407, USA;
| | - Javin P. Oza
- Department of Chemistry & Biochemistry, College of Science & Mathematics, California Polytechnic State University, San Luis Obispo, CA 93407, USA;
- Correspondence: (J.P.O.); (F.C.)
| | - Filippo Caschera
- Nuclera Nucleics Ltd., Cambridge CB4 0GD, UK
- Correspondence: (J.P.O.); (F.C.)
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4
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Abstract
The field of metabolic engineering has yielded remarkable accomplishments in using cells to produce valuable molecules, and cell-free expression (CFE) systems have the potential to push the field even further. However, CFE systems still face some outstanding challenges, including endogenous metabolic activity that is poorly understood yet has a significant impact on CFE productivity. Here, we use metabolomics to characterize the temporal metabolic changes in CFE systems and their constituent components, including significant metabolic activity in central carbon and amino acid metabolism. We find that while changing the reaction starting state via lysate preincubation impacts protein production, it has a comparatively small impact on metabolic state. We also demonstrate that changes to lysate preparation have a larger effect on protein yield and temporal metabolic profiles, though general metabolic trends are conserved. Finally, while we improve protein production through targeted supplementation of metabolic enzymes, we show that the endogenous metabolic activity is fairly resilient to these enzymatic perturbations. Overall, this work highlights the robust nature of CFE reaction metabolism as well as the importance of understanding the complex interdependence of metabolites and proteins in CFE systems to guide optimization efforts.
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Park J, Yim SS, Wang HH. High-Throughput Transcriptional Characterization of Regulatory Sequences from Bacterial Biosynthetic Gene Clusters. ACS Synth Biol 2021; 10:1859-1873. [PMID: 34288650 DOI: 10.1021/acssynbio.0c00639] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Recent efforts to sequence, survey, and functionally characterize the diverse biosynthetic capabilities of bacteria have identified numerous Biosynthetic Gene Clusters (BGCs). Genes found within BGCs are typically transcriptionally silent, suggesting their expression is tightly regulated. To better elucidate the underlying mechanisms and principles that govern BGC regulation on a DNA sequence level, we employed high-throughput DNA synthesis and multiplexed reporter assays to build and to characterize a library of BGC-derived regulatory sequences. Regulatory sequence transcription levels were measured in the Actinobacteria Streptomyces albidoflavus J1074, a popular model strain from a genus rich in BGC diversity. Transcriptional activities varied over 1000-fold in range and were used to identify key features associated with expression, including GC content, transcription start sites, and sequence motifs. Furthermore, we demonstrated that transcription levels could be modulated through coexpression of global regulatory proteins. Lastly, we developed and optimized a S. albidoflavus cell-free expression system for rapid characterization of regulatory sequences. This work helps to elucidate the regulatory landscape of BGCs and provides a diverse library of characterized regulatory sequences for rational engineering and activation of cryptic BGCs.
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Affiliation(s)
- Jimin Park
- Department of Systems Biology, Columbia University Irving Medical Center, New York, New York 10032, United States
- Integrated Program in Cellular, Molecular and Biomedical Studies, Columbia University Irving Medical Center, New York, New York 10032, United States
| | - Sung Sun Yim
- Department of Systems Biology, Columbia University Irving Medical Center, New York, New York 10032, United States
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York 10032, United States
| | - Harris H. Wang
- Department of Systems Biology, Columbia University Irving Medical Center, New York, New York 10032, United States
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York 10032, United States
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6
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Kim J, Quijano JF, Kim J, Yeung E, Murray RM. Synthetic logic circuits using RNA aptamer against T7 RNA polymerase. Biotechnol J 2021; 17:e2000449. [PMID: 33813787 DOI: 10.1002/biot.202000449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 03/05/2021] [Accepted: 03/30/2021] [Indexed: 12/23/2022]
Abstract
Recent advances in nucleic acids engineering introduced several RNA-based regulatory components for synthetic gene circuits, expanding the toolsets to engineer organisms. In this work, we designed genetic circuits implementing an RNA aptamer previously described to have the capability of binding to the T7 RNA polymerase and inhibiting its activity in vitro. We first demonstrated the utility of the RNA aptamer in combination with programmable synthetic transcription networks in vitro. As a step to quickly assess the feasibility of aptamer functions in vivo, we tested the aptamer and its sequence variants in the cell-free expression system, verifying the aptamer functionality in the cell-free testbed. The expression of aptamer in E. coli demonstrated control over GFP expression driven by T7 RNA polymerase, indicating its ability to serve as building blocks for logic circuits and transcriptional cascades. This work elucidates the potential of T7 RNA polymerase aptamer as regulators for synthetic biological circuits and metabolic engineering.
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Affiliation(s)
- Jongmin Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, Republic of Korea.,Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Juan F Quijano
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Jeongwon Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk, Republic of Korea
| | - Enoch Yeung
- Department of Control and Dynamical Systems, California Institute of Technology, Pasadena, California, USA.,Department of Mechanical Engineering, University of California, Santa Barbara, California, USA
| | - Richard M Murray
- Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA.,Department of Control and Dynamical Systems, California Institute of Technology, Pasadena, California, USA
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Abstract
Recent advances in cell-free systems have opened up new capabilities in synthetic biology from rapid prototyping of genetic circuits and metabolic pathways to portable diagnostics and biomanufacturing. A current bottleneck in cell-free systems, especially those employing non-E. coli bacterial species, is the required use of plasmid DNA, which can be laborious to construct, clone, and verify. Linear DNA templates offer a faster and more direct route for many cell-free applications, but they are often rapidly degraded in cell-free reactions. In this study, we evaluated GamS from λ-phage, DNA fragments containing Chi-sites, and Ku from Mycobacterium tuberculosis for their ability to protect linear DNA templates in diverse bacterial cell-free systems. We show that these nuclease inhibitors exhibit differential protective activities against endogenous exonucleases in five different cell-free lysates, highlighting their utility for diverse bacterial species. We expect these linear DNA protection strategies will accelerate high-throughput approaches in cell-free synthetic biology.
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Affiliation(s)
- Sung Sun Yim
- Department of Systems Biology, Columbia University, New York, New York 10027, United States
| | - Nathan I. Johns
- Department of Systems Biology, Columbia University, New York, New York 10027, United States
- Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University, New York, New York 10027, United States
| | - Vincent Noireaux
- School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Harris H. Wang
- Department of Systems Biology, Columbia University, New York, New York 10027, United States
- Department of Pathology and Cell Biology, Columbia University, New York, New York 10027, United States
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8
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Yim SS, Johns NI, Park J, Gomes ALC, McBee RM, Richardson M, Ronda C, Chen SP, Garenne D, Noireaux V, Wang HH. Multiplex transcriptional characterizations across diverse bacterial species using cell-free systems. Mol Syst Biol 2019; 15:e8875. [PMID: 31464371 PMCID: PMC6692573 DOI: 10.15252/msb.20198875] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 12/14/2022] Open
Abstract
Cell-free expression systems enable rapid prototyping of genetic programs in vitro. However, current throughput of cell-free measurements is limited by the use of channel-limited fluorescent readouts. Here, we describe DNA Regulatory element Analysis by cell-Free Transcription and Sequencing (DRAFTS), a rapid and robust in vitro approach for multiplexed measurement of transcriptional activities from thousands of regulatory sequences in a single reaction. We employ this method in active cell lysates developed from ten diverse bacterial species. Interspecies analysis of transcriptional profiles from > 1,000 diverse regulatory sequences reveals functional differences in promoter activity that can be quantitatively modeled, providing a rich resource for tuning gene expression in diverse bacterial species. Finally, we examine the transcriptional capacities of dual-species hybrid lysates that can simultaneously harness gene expression properties of multiple organisms. We expect that this cell-free multiplex transcriptional measurement approach will improve genetic part prototyping in new bacterial chassis for synthetic biology.
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Affiliation(s)
- Sung Sun Yim
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
| | - Nathan I Johns
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
- Integrated Program in Cellular, Molecular, and Biomedical StudiesColumbia UniversityNew YorkNYUSA
- Present address:
Department of BioengineeringStanford UniversityStanfordCAUSA
| | - Jimin Park
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
- Integrated Program in Cellular, Molecular, and Biomedical StudiesColumbia UniversityNew YorkNYUSA
| | - Antonio LC Gomes
- Department of ImmunologyMemorial Sloan Kettering Cancer CenterNew YorkNYUSA
| | - Ross M McBee
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
- Department of Biological SciencesColumbia UniversityNew YorkNYUSA
| | - Miles Richardson
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
- Integrated Program in Cellular, Molecular, and Biomedical StudiesColumbia UniversityNew YorkNYUSA
| | - Carlotta Ronda
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
| | - Sway P Chen
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
- Integrated Program in Cellular, Molecular, and Biomedical StudiesColumbia UniversityNew YorkNYUSA
| | - David Garenne
- School of Physics and AstronomyUniversity of MinnesotaMinneapolisMNUSA
| | - Vincent Noireaux
- School of Physics and AstronomyUniversity of MinnesotaMinneapolisMNUSA
| | - Harris H Wang
- Department of Systems BiologyColumbia UniversityNew YorkNYUSA
- Department of Pathology and Cell BiologyColumbia UniversityNew YorkNYUSA
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