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Bispecific Antibody Molecule Inhibits Tumor Cell Proliferation More Efficiently Than the Two-Molecule Combination. Drugs R D 2021; 21:157-168. [PMID: 33721246 PMCID: PMC8206453 DOI: 10.1007/s40268-021-00339-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2021] [Indexed: 11/21/2022] Open
Abstract
Background Monoclonal antibodies (mAbs) have proved to be a valuable tool for the treatment of different cancer types. However, clinical use of an increasing number of mAbs, have also highlighted limitations with monotherapy for cancers, in particular for such with more complex mechanisms, requiring action on additional molecules or pathways, or for cancers quickly acquiring resistance following monotherapy. An example for the latter is the mAb trastuzumab, FDA approved for treatment of metastatic gastric carcinoma. To circumvent this, researchers have reported synergistic, anti-proliferative effects by combination targeting of HER2 and EGFR by trastuzumab and the EGFR-targeting mAb Cetuximab overcoming trastuzumab resistance. Methods Maintaining the proven functionality of trastuzumab, we have designed bi-specific antibody molecules, called AffiMabs, by fusing an EGFR-targeting Affibody molecule to trastuzumab’s heavy or light chains. Having confirmed binding to EGFR and Her2 and cytotoxicity of our AffiMabs, we analyzed apoptosis rate, receptor surface levels, phosphorylation levels of receptors and associated signaling pathways as well as differentially expressed genes on transcriptome level with the aim to elucidate the mode of action of our AffiMabs. Results The AffiMabs are able to simultaneously bind HER2 and EGFR and show increased cytotoxic effect compared to the original trastuzumab therapeutic molecule and, more importantly, even to the combination of trastuzumab and EGFR-targeting Affibody molecule. Analyzing the mode of action, we could show that bi-specific AffiMabs lead to reduced surface receptor levels and a downregulation of cell cycle associated genes on transcriptome level. Conclusion Our study shows that transcriptome analysis can be used to validate the choice of receptor targets and guide the design of novel multi-specific molecules. The inherent modularity of the AffiMab format renders it readily applicable to other receptor targets. Supplementary Information The online version contains supplementary material available at 10.1007/s40268-021-00339-2.
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Eisenhut P, Mebrahtu A, Moradi Barzadd M, Thalén N, Klanert G, Weinguny M, Sandegren A, Su C, Hatton D, Borth N, Rockberg J. Systematic use of synthetic 5'-UTR RNA structures to tune protein translation improves yield and quality of complex proteins in mammalian cell factories. Nucleic Acids Res 2020; 48:e119. [PMID: 33051690 PMCID: PMC7672427 DOI: 10.1093/nar/gkaa847] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 08/28/2020] [Accepted: 09/22/2020] [Indexed: 12/30/2022] Open
Abstract
Predictably regulating protein expression levels to improve recombinant protein production has become an important tool, but is still rarely applied to engineer mammalian cells. We therefore sought to set-up an easy-to-implement toolbox to facilitate fast and reliable regulation of protein expression in mammalian cells by introducing defined RNA hairpins, termed 'regulation elements (RgE)', in the 5'-untranslated region (UTR) to impact translation efficiency. RgEs varying in thermodynamic stability, GC-content and position were added to the 5'-UTR of a fluorescent reporter gene. Predictable translation dosage over two orders of magnitude in mammalian cell lines of hamster and human origin was confirmed by flow cytometry. Tuning heavy chain expression of an IgG with the RgEs to various levels eventually resulted in up to 3.5-fold increased titers and fewer IgG aggregates and fragments in CHO cells. Co-expression of a therapeutic Arylsulfatase-A with RgE-tuned levels of the required helper factor SUMF1 demonstrated that the maximum specific sulfatase activity was already attained at lower SUMF1 expression levels, while specific production rates steadily decreased with increasing helper expression. In summary, we show that defined 5'-UTR RNA-structures represent a valid tool to systematically tune protein expression levels in mammalian cells and eventually help to optimize recombinant protein expression.
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Affiliation(s)
- Peter Eisenhut
- ACIB Austrian Centre of Industrial Biotechnology, Krenngasse 37, 8010 Graz, Austria
- BOKU University of Natural Resources and Life Sciences, Department of Biotechnology, Vienna 1190, Austria
| | - Aman Mebrahtu
- KTH Royal Institute of Technology, Department of Protein Science, 10691 Stockholm, Sweden
| | - Mona Moradi Barzadd
- KTH Royal Institute of Technology, Department of Protein Science, 10691 Stockholm, Sweden
| | - Niklas Thalén
- KTH Royal Institute of Technology, Department of Protein Science, 10691 Stockholm, Sweden
| | - Gerald Klanert
- ACIB Austrian Centre of Industrial Biotechnology, Krenngasse 37, 8010 Graz, Austria
| | - Marcus Weinguny
- ACIB Austrian Centre of Industrial Biotechnology, Krenngasse 37, 8010 Graz, Austria
- BOKU University of Natural Resources and Life Sciences, Department of Biotechnology, Vienna 1190, Austria
| | - Anna Sandegren
- Affibody Medical AB, Scheeles väg 2, SE-171 65 Solna, Sweden
| | - Chao Su
- SOBI AB, Tomtebodavägen 23A, Stockholm, Sweden
| | - Diane Hatton
- AstraZeneca, Biopharmaceutical Development, Milstein Building, Granta Park, Cambridge CB21 6GH, UK
| | - Nicole Borth
- ACIB Austrian Centre of Industrial Biotechnology, Krenngasse 37, 8010 Graz, Austria
- BOKU University of Natural Resources and Life Sciences, Department of Biotechnology, Vienna 1190, Austria
| | - Johan Rockberg
- KTH Royal Institute of Technology, Department of Protein Science, 10691 Stockholm, Sweden
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3
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Lindenburg L, Huovinen T, van de Wiel K, Herger M, Snaith MR, Hollfelder F. Split & mix assembly of DNA libraries for ultrahigh throughput on-bead screening of functional proteins. Nucleic Acids Res 2020; 48:e63. [PMID: 32383757 PMCID: PMC7293038 DOI: 10.1093/nar/gkaa270] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/02/2020] [Accepted: 04/21/2020] [Indexed: 12/13/2022] Open
Abstract
Site-saturation libraries reduce protein screening effort in directed evolution campaigns by focusing on a limited number of rationally chosen residues. However, uneven library synthesis efficiency leads to amino acid bias, remedied at high cost by expensive custom synthesis of oligonucleotides, or through use of proprietary library synthesis platforms. To address these shortcomings, we have devised a method where DNA libraries are constructed on the surface of microbeads by ligating dsDNA fragments onto growing, surface-immobilised DNA, in iterative split-and-mix cycles. This method-termed SpliMLiB for Split-and-Mix Library on Beads-was applied towards the directed evolution of an anti-IgE Affibody (ZIgE), generating a 160,000-membered, 4-site, saturation library on the surface of 8 million monoclonal beads. Deep sequencing confirmed excellent library balance (5.1% ± 0.77 per amino acid) and coverage (99.3%). As SpliMLiB beads are monoclonal, they were amenable to direct functional screening in water-in-oil emulsion droplets with cell-free expression. A FACS-based sorting of the library beads allowed recovery of hits improved in Kd over wild-type ZIgE by up to 3.5-fold, while a consensus mutant of the best hits provided a 10-fold improvement. With SpliMLiB, directed evolution workflows are accelerated by integrating high-quality DNA library generation with an ultra-high throughput protein screening platform.
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Affiliation(s)
- Laurens Lindenburg
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK
| | - Tuomas Huovinen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK
| | - Kayleigh van de Wiel
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK
| | - Michael Herger
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK
- AstraZeneca Medimmune Cambridge, Antibody Discovery and Protein Engineering, Cambridge, UK
| | - Michael R Snaith
- AstraZeneca Medimmune Cambridge, Antibody Discovery and Protein Engineering, Cambridge, UK
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Rd, Cambridge CB2 1GA, UK
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4
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Schmidt C, Schierack P, Gerber U, Schröder C, Choi Y, Bald I, Lehmann W, Rödiger S. Streptavidin Homologues for Applications on Solid Surfaces at High Temperatures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:628-636. [PMID: 31895565 DOI: 10.1021/acs.langmuir.9b02339] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
One of the most commonly used bonds between two biomolecules is the bond between biotin and streptavidin (SA) or streptavidin homologues (SAHs). A high dissociation constant and the consequent high-temperature stability even allows for its use in nucleic acid detection under polymerase chain reaction (PCR) conditions. There are a number of SAHs available, and for assay design, it is of great interest to determine as to which SAH will perform the best under assay conditions. Although there are numerous single studies on the characterization of SAHs in solution or selected solid phases, there is no systematic study comparing different SAHs for biomolecule-binding, hybridization, and PCR assays on solid phases. We compared streptavidin, core streptavidin, traptavidin, core traptavidin, neutravidin, and monomeric streptavidin on the surface of microbeads (10-15 μm in diameter) and designed multiplex microbead-based experiments and analyzed simultaneously the binding of biotinylated oligonucleotides and the hybridization of oligonucleotides to complementary capture probes. We also bound comparably large DNA origamis to capture probes on the microbead surface. We used a real-time fluorescence microscopy imaging platform, with which it is possible to subject samples to a programmable time and temperature profile and to record binding processes on the microbead surface depending on the time and temperature. With the exception of core traptavidin and monomeric streptavidin, all other SA/SAHs were suitable for our investigations. We found hybridization efficiencies close to 100% for streptavidin, core streptavidin, traptavidin, and neutravidin. These could all be considered equally suitable for hybridization, PCR applications, and melting point analysis. The SA/SAH-biotin bond was temperature-sensitive when the oligonucleotide was mono-biotinylated, with traptavidin being the most stable followed by streptavidin and neutravidin. Mono-biotinylated oligonucleotides can be used in experiments with temperatures up to 70 °C. When oligonucleotides were bis-biotinylated, all SA/SAH-biotin bonds had similar temperature stability under PCR conditions, even if they comprised a streptavidin variant with slower biotin dissociation and increased mechanostability.
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Affiliation(s)
- Carsten Schmidt
- Faculty of Environment and Natural Sciences, Institute of Biotechnology , Brandenburg University of Technology Cottbus-Senftenberg , Universitätsplatz 1 , D-01968 Senftenberg , Germany
| | - Peter Schierack
- Faculty of Environment and Natural Sciences, Institute of Biotechnology , Brandenburg University of Technology Cottbus-Senftenberg , Universitätsplatz 1 , D-01968 Senftenberg , Germany
| | - Ulrike Gerber
- Faculty of Environment and Natural Sciences, Institute of Biotechnology , Brandenburg University of Technology Cottbus-Senftenberg , Universitätsplatz 1 , D-01968 Senftenberg , Germany
| | - Christian Schröder
- Faculty of Environment and Natural Sciences, Institute of Biotechnology , Brandenburg University of Technology Cottbus-Senftenberg , Universitätsplatz 1 , D-01968 Senftenberg , Germany
| | - Youngeun Choi
- Optical Spectroscopy and Chemical Imaging, Institute of Chemistry , University of Potsdam , Karl-Liebknecht-Straße 24-25, Building 29 , D-14476 Potsdam , Germany
- Division 1-Analytical Chemistry and Reference Materials , BAM Federal Institute for Materials Research and Testing , Richard-Willstätter Str. 11 , 12489 Berlin , Germany
| | - Ilko Bald
- Optical Spectroscopy and Chemical Imaging, Institute of Chemistry , University of Potsdam , Karl-Liebknecht-Straße 24-25, Building 29 , D-14476 Potsdam , Germany
- Division 1-Analytical Chemistry and Reference Materials , BAM Federal Institute for Materials Research and Testing , Richard-Willstätter Str. 11 , 12489 Berlin , Germany
| | - Werner Lehmann
- Attomol GmbH , Schulweg 6 , D-03205 Bronkow , Lipten, Germany
| | - Stefan Rödiger
- Faculty of Environment and Natural Sciences, Institute of Biotechnology , Brandenburg University of Technology Cottbus-Senftenberg , Universitätsplatz 1 , D-01968 Senftenberg , Germany
- Faculty of Health Sciences , Joint Faculty of the Brandenburg University of Technology Cottbus-Senftenberg, The Brandenburg Medical School Theodor Fontane and The University of Potsdam , D-01968 Senftenberg , Germany
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5
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Hu FJ, Lundqvist M, Uhlén M, Rockberg J. SAMURAI (Solid-phase Assisted Mutagenesis by Uracil Restriction for Accurate Integration) for antibody affinity maturation and paratope mapping. Nucleic Acids Res 2019; 47:e34. [PMID: 30715449 PMCID: PMC6451119 DOI: 10.1093/nar/gkz050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/08/2019] [Accepted: 01/24/2019] [Indexed: 12/31/2022] Open
Abstract
Mutagenesis libraries are essential for combinatorial protein engineering. Despite improvements in gene synthesis and directed mutagenesis, current methodologies still have limitations regarding the synthesis of complete antibody single-chain variable fragment (scFv) genes and simultaneous diversification of all six CDRs. Here, we describe the generation of mutagenesis libraries for antibody affinity maturation using a cell-free solid-phase technique for annealing of single-strand mutagenic oligonucleotides. The procedure consists of PCR-based incorporation of uracil into a wild-type template, bead-based capture, elution of single-strand DNA, and in vitro uracil excision enzyme based degradation of the template DNA. Our approach enabled rapid (8 hours) mutagenesis and automated cloning of 50 position-specific alanine mutants for mapping of a scFv antibody paratope. We further exemplify our method by generating affinity maturation libraries with diversity introduced in critical, nonessential, or all CDR positions randomly. Assessment with Illumina deep sequencing showed less than 1% wild-type in two libraries and the ability to diversify all CDR positions simultaneously. Selections of the libraries with bacterial display and deep sequencing evaluation of the selection output showed that diversity introduced in non-essential positions allowed for a more effective enrichment of improved binders compared to the other two diversification strategies.
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Affiliation(s)
- Francis Jingxin Hu
- KTH - Royal Institute of Technology, Department of Protein Science, 106 91 Stockholm, Sweden
| | - Magnus Lundqvist
- KTH - Royal Institute of Technology, Department of Protein Science, 106 91 Stockholm, Sweden
| | - Mathias Uhlén
- KTH - Royal Institute of Technology, Department of Protein Science, 106 91 Stockholm, Sweden.,KTH - Royal Institute of Technology, Science for Life Laboratory, Solna 171 65, Sweden.,Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2970 Hørsholm, Denmark
| | - Johan Rockberg
- KTH - Royal Institute of Technology, Department of Protein Science, 106 91 Stockholm, Sweden
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6
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Hu FJ, Volk AL, Persson H, Säll A, Borrebaeck C, Uhlen M, Rockberg J. Combination of phage and Gram-positive bacterial display of human antibody repertoires enables isolation of functional high affinity binders. N Biotechnol 2018; 45:80-88. [DOI: 10.1016/j.nbt.2017.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/28/2017] [Accepted: 07/31/2017] [Indexed: 10/19/2022]
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7
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Sastry A, Monk J, Tegel H, Uhlen M, Palsson BO, Rockberg J, Brunk E. Machine learning in computational biology to accelerate high-throughput protein expression. Bioinformatics 2018; 33:2487-2495. [PMID: 28398465 DOI: 10.1093/bioinformatics/btx207] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 04/05/2017] [Indexed: 01/21/2023] Open
Abstract
Motivation The Human Protein Atlas (HPA) enables the simultaneous characterization of thousands of proteins across various tissues to pinpoint their spatial location in the human body. This has been achieved through transcriptomics and high-throughput immunohistochemistry-based approaches, where over 40 000 unique human protein fragments have been expressed in E. coli. These datasets enable quantitative tracking of entire cellular proteomes and present new avenues for understanding molecular-level properties influencing expression and solubility. Results Combining computational biology and machine learning identifies protein properties that hinder the HPA high-throughput antibody production pipeline. We predict protein expression and solubility with accuracies of 70% and 80%, respectively, based on a subset of key properties (aromaticity, hydropathy and isoelectric point). We guide the selection of protein fragments based on these characteristics to optimize high-throughput experimentation. Availability and implementation We present the machine learning workflow as a series of IPython notebooks hosted on GitHub (https://github.com/SBRG/Protein_ML). The workflow can be used as a template for analysis of further expression and solubility datasets. Contact ebrunk@ucsd.edu or johanr@biotech.kth.se. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Anand Sastry
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Jonathan Monk
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Hanna Tegel
- KTH - Royal Institute of Technology, Department of Proteomics and Nanobiotechnology, SE-106 91 Stockholm, Sweden
| | - Mathias Uhlen
- KTH - Royal Institute of Technology, Department of Proteomics and Nanobiotechnology, SE-106 91 Stockholm, Sweden.,The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, CA, USA.,The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Lyngby, Denmark
| | - Johan Rockberg
- KTH - Royal Institute of Technology, Department of Proteomics and Nanobiotechnology, SE-106 91 Stockholm, Sweden
| | - Elizabeth Brunk
- Department of Bioengineering, University of California, San Diego, CA, USA.,The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Lyngby, Denmark
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8
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Mehrotra R, Renganaath K, Kanodia H, Loake GJ, Mehrotra S. Towards combinatorial transcriptional engineering. Biotechnol Adv 2017; 35:390-405. [PMID: 28300614 DOI: 10.1016/j.biotechadv.2017.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/22/2017] [Accepted: 03/09/2017] [Indexed: 01/31/2023]
Abstract
The modular nature of the transcriptional unit makes it possible to design robust modules with predictable input-output characteristics using a ‘parts- off a shelf’ approach. Customized regulatory circuits composed of multiple such transcriptional units have immense scope for application in diverse fields of basic and applied research. Synthetic transcriptional engineering seeks to construct such genetic cascades. Here, we discuss the three principle strands of transcriptional engineering: promoter and transcriptional factor engineering, and programming inducibilty into synthetic modules. In this context, we review the scope and limitations of some recent technologies that seek to achieve these ends. Our discussion emphasizes a requirement for rational combinatorial engineering principles and the promise this approach holds for the future development of this field.
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Affiliation(s)
- Rajesh Mehrotra
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS) Pilani, Pilani 333031, Rajasthan, India.
| | - Kaushik Renganaath
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS) Pilani, Pilani 333031, Rajasthan, India
| | - Harsh Kanodia
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS) Pilani, Pilani 333031, Rajasthan, India
| | - Gary J Loake
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, The King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, United Kingdom
| | - Sandhya Mehrotra
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS) Pilani, Pilani 333031, Rajasthan, India
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9
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Blackburn MC, Petrova E, Correia BE, Maerkl SJ. Integrating gene synthesis and microfluidic protein analysis for rapid protein engineering. Nucleic Acids Res 2015; 44:e68. [PMID: 26704969 PMCID: PMC4838357 DOI: 10.1093/nar/gkv1497] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/09/2015] [Indexed: 11/15/2022] Open
Abstract
The capability to rapidly design proteins with novel functions will have a significant impact on medicine, biotechnology and synthetic biology. Synthetic genes are becoming a commodity, but integrated approaches have yet to be developed that take full advantage of gene synthesis. We developed a solid-phase gene synthesis method based on asymmetric primer extension (APE) and coupled this process directly to high-throughput, on-chip protein expression, purification and characterization (via mechanically induced trapping of molecular interactions, MITOMI). By completely circumventing molecular cloning and cell-based steps, APE-MITOMI reduces the time between protein design and quantitative characterization to 3–4 days. With APE-MITOMI we synthesized and characterized over 400 zinc-finger (ZF) transcription factors (TF), showing that although ZF TFs can be readily engineered to recognize a particular DNA sequence, engineering the precise binding energy landscape remains challenging. We also found that it is possible to engineer ZF–DNA affinity precisely and independently of sequence specificity and that in silico modeling can explain some of the observed affinity differences. APE-MITOMI is a generic approach that should facilitate fundamental studies in protein biophysics, and protein design/engineering.
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Affiliation(s)
- Matthew C Blackburn
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ekaterina Petrova
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Bruno E Correia
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Sebastian J Maerkl
- Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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10
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Versatile microscale screening platform for improving recombinant protein productivity in Chinese hamster ovary cells. Sci Rep 2015; 5:18016. [PMID: 26657798 PMCID: PMC4676018 DOI: 10.1038/srep18016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/10/2015] [Indexed: 11/09/2022] Open
Abstract
Chinese hamster ovary (CHO) cells are widely used as cell factories for the production of biopharmaceuticals. In contrast to the highly optimized production processes for monoclonal antibody (mAb)-based biopharmaceuticals, improving productivity of non-mAb therapeutic glycoproteins is more likely to reduce production costs significantly. The aim of this study was to establish a versatile target gene screening platform for improving productivity for primarily non-mAb glycoproteins with complete interchangeability of model proteins and target genes using transient expression. The platform consists of four techniques compatible with 96-well microplates: lipid-based transient transfection, cell cultivation in microplates, cell counting and antibody-independent product titer determination based on split-GFP complementation. We were able to demonstrate growth profiles and volumetric productivity of CHO cells in 96-half-deepwell microplates comparable with those obtained in shake flasks. In addition, we demonstrate that split-GFP complementation can be used to accurately measure relative titers of therapeutic glycoproteins. Using this platform, we were able to detect target gene-specific increase in titer and specific productivity of two non-mAb glycoproteins. In conclusion, the platform provides a novel miniaturized and parallelisable solution for screening target genes and holds the potential to unravel genes that can enhance the secretory capacity of CHO cells.
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11
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Gene and library synthesis without amplification: polymerase step reaction (PSR). Biotechniques 2015; 59:163-6. [PMID: 26345510 DOI: 10.2144/000114330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 07/02/2015] [Indexed: 11/23/2022] Open
Abstract
Current gene synthesis methods often incorporate a PCR amplification step in order to yield final material sufficient for resolution from multiple off-products. These amplification steps can cause stochastic sampling effects that propagate errors in gene synthesis or decrease variability when applied to the construction of randomized libraries. We have developed a simple DNA polymerase-based gene synthesis reaction, polymerase step reaction (PSR), that assembles DNA oligonucleotides in a unidirectional fashion without the need for amplification. We demonstrate that PSR is efficient, with little off-product production, no detectable error propagation, and maximized variability in the synthesis of a phage display library.
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