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Vercauteren S, Fiesack S, Maroc L, Verstraeten N, Dewachter L, Michiels J, Vonesch SC. The rise and future of CRISPR-based approaches for high-throughput genomics. FEMS Microbiol Rev 2024; 48:fuae020. [PMID: 39085047 PMCID: PMC11409895 DOI: 10.1093/femsre/fuae020] [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: 05/08/2024] [Revised: 07/19/2024] [Accepted: 07/30/2024] [Indexed: 08/02/2024] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) has revolutionized the field of genome editing. To circumvent the permanent modifications made by traditional CRISPR techniques and facilitate the study of both essential and nonessential genes, CRISPR interference (CRISPRi) was developed. This gene-silencing technique employs a deactivated Cas effector protein and a guide RNA to block transcription initiation or elongation. Continuous improvements and a better understanding of the mechanism of CRISPRi have expanded its scope, facilitating genome-wide high-throughput screens to investigate the genetic basis of phenotypes. Additionally, emerging CRISPR-based alternatives have further expanded the possibilities for genetic screening. This review delves into the mechanism of CRISPRi, compares it with other high-throughput gene-perturbation techniques, and highlights its superior capacities for studying complex microbial traits. We also explore the evolution of CRISPRi, emphasizing enhancements that have increased its capabilities, including multiplexing, inducibility, titratability, predictable knockdown efficacy, and adaptability to nonmodel microorganisms. Beyond CRISPRi, we discuss CRISPR activation, RNA-targeting CRISPR systems, and single-nucleotide resolution perturbation techniques for their potential in genome-wide high-throughput screens in microorganisms. Collectively, this review gives a comprehensive overview of the general workflow of a genome-wide CRISPRi screen, with an extensive discussion of strengths and weaknesses, future directions, and potential alternatives.
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Affiliation(s)
- Silke Vercauteren
- Center for Microbiology, VIB - KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, box 2460, 3001 Leuven, Belgium
| | - Simon Fiesack
- Center for Microbiology, VIB - KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, box 2460, 3001 Leuven, Belgium
| | - Laetitia Maroc
- Center for Microbiology, VIB - KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, box 2460, 3001 Leuven, Belgium
| | - Natalie Verstraeten
- Center for Microbiology, VIB - KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, box 2460, 3001 Leuven, Belgium
| | - Liselot Dewachter
- de Duve Institute, Université catholique de Louvain, Hippokrateslaan 75, 1200 Brussels, Belgium
| | - Jan Michiels
- Center for Microbiology, VIB - KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, box 2460, 3001 Leuven, Belgium
| | - Sibylle C Vonesch
- Center for Microbiology, VIB - KU Leuven, Gaston Geenslaan 1, 3001 Leuven, Belgium
- Centre of Microbial and Plant Genetics, KU Leuven, Kasteelpark Arenberg 20, box 2460, 3001 Leuven, Belgium
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2
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Park JH, Holló G, Schaerli Y. From resonance to chaos by modulating spatiotemporal patterns through a synthetic optogenetic oscillator. Nat Commun 2024; 15:7284. [PMID: 39179558 PMCID: PMC11343849 DOI: 10.1038/s41467-024-51626-w] [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: 04/09/2024] [Accepted: 08/14/2024] [Indexed: 08/26/2024] Open
Abstract
Oscillations are a recurrent phenomenon in biological systems across scales, but deciphering their fundamental principles is very challenging. Here, we tackle this challenge by redesigning the wellcharacterised synthetic oscillator known as "repressilator" in Escherichia coli and controlling it using optogenetics, creating the "optoscillator". Bacterial colonies manifest oscillations as spatial ring patterns. When we apply periodic light pulses, the optoscillator behaves as a forced oscillator and we systematically investigate the properties of the rings under various light conditions. Combining experiments with mathematical modeling, we demonstrate that this simple oscillatory circuit can generate complex dynamics that are transformed into distinct spatial patterns. We report the observation of synchronisation, resonance, subharmonic resonance and period doubling. Furthermore, we present evidence of a chaotic regime. This work highlights the intricate spatiotemporal patterns accessible by synthetic oscillators and underscores the potential of our approach in revealing fundamental principles of biological oscillations.
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Affiliation(s)
- Jung Hun Park
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Gábor Holló
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
| | - Yolanda Schaerli
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
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3
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Lau CH, Liang QL, Zhu H. Next-generation CRISPR technology for genome, epigenome and mitochondrial editing. Transgenic Res 2024:10.1007/s11248-024-00404-x. [PMID: 39158822 DOI: 10.1007/s11248-024-00404-x] [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: 06/04/2024] [Accepted: 08/08/2024] [Indexed: 08/20/2024]
Abstract
The application of rapidly growing CRISPR toolboxes and methods has great potential to transform biomedical research. Here, we provide a snapshot of up-to-date CRISPR toolboxes, then critically discuss the promises and hurdles associated with CRISPR-based nuclear genome editing, epigenome editing, and mitochondrial editing. The technical challenges and key solutions to realize epigenome editing in vivo, in vivo base editing and prime editing, mitochondrial editing in complex tissues and animals, and CRISPR-associated transposases and integrases in targeted genomic integration of very large DNA payloads are discussed. Lastly, we discuss the latest situation of the CRISPR/Cas9 clinical trials and provide perspectives on CRISPR-based gene therapy. Apart from technical shortcomings, ethical and societal considerations for CRISPR applications in human therapeutics and research are extensively highlighted.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biology, College of Science, Shantou University, Shantou, 515063, Guangdong, China
| | - Qing-Le Liang
- Department of Clinical Laboratory Medicine, Chongqing University Jiangjin Hospital, Chongqing, China
| | - Haibao Zhu
- Department of Biology, College of Science, Shantou University, Shantou, 515063, Guangdong, China.
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4
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Rueff AS, van Raaphorst R, Aggarwal SD, Santos-Moreno J, Laloux G, Schaerli Y, Weiser JN, Veening JW. Synthetic genetic oscillators demonstrate the functional importance of phenotypic variation in pneumococcal-host interactions. Nat Commun 2023; 14:7454. [PMID: 37978173 PMCID: PMC10656556 DOI: 10.1038/s41467-023-43241-y] [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: 06/02/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023] Open
Abstract
Phenotypic variation is the phenomenon in which clonal cells display different traits even under identical environmental conditions. This plasticity is thought to be important for processes including bacterial virulence, but direct evidence for its relevance is often lacking. For instance, variation in capsule production in the human pathogen Streptococcus pneumoniae has been linked to different clinical outcomes, but the exact relationship between variation and pathogenesis is not well understood due to complex natural regulation. In this study, we use synthetic oscillatory gene regulatory networks (GRNs) based on CRISPR interference (CRISPRi) together with live cell imaging and cell tracking within microfluidics devices to mimic and test the biological function of bacterial phenotypic variation. We provide a universally applicable approach for engineering intricate GRNs using only two components: dCas9 and extended sgRNAs (ext-sgRNAs). Our findings demonstrate that variation in capsule production is beneficial for pneumococcal fitness in traits associated with pathogenesis providing conclusive evidence for this longstanding question.
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Affiliation(s)
- Anne-Stéphanie Rueff
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
| | - Renske van Raaphorst
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
- de Duve Institute, UCLouvain, 75 Avenue Hippocrate, 1200, Brussels, Belgium
| | - Surya D Aggarwal
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Javier Santos-Moreno
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
- Pompeu Fabra University, Barcelona, Spain
| | - Géraldine Laloux
- de Duve Institute, UCLouvain, 75 Avenue Hippocrate, 1200, Brussels, Belgium
| | - Yolanda Schaerli
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland
| | - Jeffrey N Weiser
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015, Lausanne, Switzerland.
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA.
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA.
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5
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Xia Y, Li Y, Shen W, Yang H, Chen X. CRISPR-Cas Technology for Bioengineering Conventional and Non-Conventional Yeasts: Progress and New Challenges. Int J Mol Sci 2023; 24:15310. [PMID: 37894990 PMCID: PMC10607330 DOI: 10.3390/ijms242015310] [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: 08/24/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein (CRISPR-Cas) system has undergone substantial and transformative progress. Simultaneously, a spectrum of derivative technologies has emerged, spanning both conventional and non-conventional yeast strains. Non-conventional yeasts, distinguished by their robust metabolic pathways, formidable resilience against diverse stressors, and distinctive regulatory mechanisms, have emerged as a highly promising alternative for diverse industrial applications. This comprehensive review serves to encapsulate the prevailing gene editing methodologies and their associated applications within the traditional industrial microorganism, Saccharomyces cerevisiae. Additionally, it delineates the current panorama of non-conventional yeast strains, accentuating their latent potential in the realm of industrial and biotechnological utilization. Within this discourse, we also contemplate the potential value these tools offer alongside the attendant challenges they pose.
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Affiliation(s)
- Yuanyuan Xia
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Y.X.); (Y.L.); (W.S.); (H.Y.)
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yujie Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Y.X.); (Y.L.); (W.S.); (H.Y.)
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Wei Shen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Y.X.); (Y.L.); (W.S.); (H.Y.)
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Haiquan Yang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Y.X.); (Y.L.); (W.S.); (H.Y.)
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xianzhong Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 214122, China; (Y.X.); (Y.L.); (W.S.); (H.Y.)
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
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6
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Rueff AS, van Raaphorst R, Aggarwal S, Santos-Moreno J, Laloux G, Schaerli Y, Weiser JN, Veening JW. Rewiring capsule production by CRISPRi-based genetic oscillators demonstrates a functional role of phenotypic variation in pneumococcal-host interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.03.543575. [PMID: 37398107 PMCID: PMC10312626 DOI: 10.1101/2023.06.03.543575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Phenotypic variation is the phenomenon in which clonal cells display different traits even under identical environmental conditions. This plasticity is thought to be important for processes including bacterial virulence1-8, but direct evidence for its relevance is often lacking. For instance, variation in capsule production in the human pathogen Streptococcus pneumoniae has been linked to different clinical outcomes9-14, but the exact relationship between variation and pathogenesis is not well understood due to complex natural regulation15-20. In this study, we used synthetic oscillatory gene regulatory networks (GRNs) based on CRISPR interference together with live cell microscopy and cell tracking within microfluidics devices to mimic and test the biological function of bacterial phenotypic variation. We provide a universally applicable approach for engineering intricate GRNs using only two components: dCas9 and extended sgRNAs (ext-sgRNAs). Our findings demonstrate that variation in capsule production is beneficial for pneumococcal fitness in traits associated with pathogenesis providing conclusive evidence for this longstanding question.
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Affiliation(s)
- Anne-Stéphanie Rueff
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Renske van Raaphorst
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
- de Duve Institute, UCLouvain, 75 Avenue Hippocrate, 1200 Brussels, Belgium
| | - Surya Aggarwal
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Javier Santos-Moreno
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
- Present address: Pompeu Fabra University, Barcelona, Spain
| | - Géraldine Laloux
- de Duve Institute, UCLouvain, 75 Avenue Hippocrate, 1200 Brussels, Belgium
| | - Yolanda Schaerli
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
| | - Jeffrey N. Weiser
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
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7
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Gao J, Liu H, Zhang Z, Liang Z. Establishment, optimization, and application of genetic technology in Aspergillus spp. Front Microbiol 2023; 14:1141869. [PMID: 37025635 PMCID: PMC10071863 DOI: 10.3389/fmicb.2023.1141869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/27/2023] [Indexed: 04/08/2023] Open
Abstract
Aspergillus is widely distributed in nature and occupies a crucial ecological niche, which has complex and diverse metabolic pathways and can produce a variety of metabolites. With the deepening of genomics exploration, more Aspergillus genomic informations have been elucidated, which not only help us understand the basic mechanism of various life activities, but also further realize the ideal functional transformation. Available genetic engineering tools include homologous recombinant systems, specific nuclease based systems, and RNA techniques, combined with transformation methods, and screening based on selective labeling. Precise editing of target genes can not only prevent and control the production of mycotoxin pollutants, but also realize the construction of economical and efficient fungal cell factories. This paper reviewed the establishment and optimization process of genome technologies, hoping to provide the theoretical basis of experiments, and summarized the recent progress and application in genetic technology, analyzes the challenges and the possibility of future development with regard to Aspergillus.
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Affiliation(s)
- Jing Gao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Huiqing Liu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Zhenzhen Zhang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Zhihong Liang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing, China
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- *Correspondence: Zhihong Liang,
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8
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Landau J, Cuba Samaniego C, Giordano G, Franco E. Computational characterization of recombinase circuits for periodic behaviors. iScience 2022; 26:105624. [PMID: 36619981 PMCID: PMC9812718 DOI: 10.1016/j.isci.2022.105624] [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: 11/02/2021] [Revised: 06/17/2022] [Accepted: 11/15/2022] [Indexed: 11/23/2022] Open
Abstract
Recombinases are site-specific proteins found in nature that are capable of rearranging DNA. This function has made them promising gene editing tools in synthetic biology, as well as key elements in complex artificial gene circuits implementing Boolean logic. However, since DNA rearrangement is irreversible, it is still unclear how to use recombinases to build dynamic circuits like oscillators. In addition, this goal is challenging because a few molecules of recombinase are enough for promoter inversion, generating inherent stochasticity at low copy number. Here, we propose six different circuit designs for recombinase-based oscillators operating at a single copy number. We model them in a stochastic setting, leveraging the Gillespie algorithm for extensive simulations, and show that they can yield coherent periodic behaviors. Our results support the experimental realization of recombinase-based oscillators and, more generally, the use of recombinases to generate dynamic behaviors in synthetic biology.
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Affiliation(s)
- Judith Landau
- California State University, Los Angeles, Los Angeles, CA, USA
| | | | - Giulia Giordano
- Department of Industrial Engineering, University of Trento, Trento, Italy
| | - Elisa Franco
- University of California, Los Angeles, Los Angeles, CA, USA
- Corresponding author
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9
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Specht DA, Cortes LB, Lambert G. Overcoming Leak Sensitivity in CRISPRi Circuits Using Antisense RNA Sequestration and Regulatory Feedback. ACS Synth Biol 2022; 11:2927-2937. [PMID: 36017994 PMCID: PMC9486968 DOI: 10.1021/acssynbio.2c00155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Indexed: 01/24/2023]
Abstract
The controlled binding of the catalytically dead CRISPR nuclease (dCas) to DNA can be used to create complex, programmable transcriptional genetic circuits, a fundamental goal of synthetic biology. This approach, called CRISPR interference (CRISPRi), is advantageous over existing methods because the programmable nature of CRISPR proteins in principle enables the simultaneous regulation of many different targets without crosstalk. However, the performance of dCas-based genetic circuits is limited by both the sensitivity to leaky repression within CRISPRi logic gates and retroactive effects due to a shared pool of dCas proteins. By utilizing antisense RNAs (asRNAs) to sequester gRNA transcripts as well as CRISPRi feedback to self-regulate asRNA production, we demonstrate a mechanism that suppresses unwanted repression by CRISPRi and improves logical gene circuit function in Escherichia coli. This improvement is particularly pronounced during stationary expression when CRISPRi circuits do not achieve the expected regulatory dynamics. Furthermore, the use of dual CRISPRi/asRNA inverters restores the logical performance of layered circuits such as a double inverter. By studying circuit induction at the single-cell level in microfluidic channels, we provide insight into the dynamics of antisense sequestration of gRNA and regulatory feedback on dCas-based repression and derepression. These results demonstrate how CRISPRi inverters can be improved for use in more complex genetic circuitry without sacrificing the programmability and orthogonality of dCas proteins.
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Affiliation(s)
- David A. Specht
- Applied Physics, Cornell University, Ithaca, New York 14853, United States
| | - Louis B. Cortes
- Applied Physics, Cornell University, Ithaca, New York 14853, United States
| | - Guillaume Lambert
- Applied Physics, Cornell University, Ithaca, New York 14853, United States
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10
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Wang Z, Chen G. Insights about circadian clock in glioma: From molecular pathways to therapeutic drugs. CNS Neurosci Ther 2022; 28:1930-1941. [PMID: 36066207 PMCID: PMC9627379 DOI: 10.1111/cns.13966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 02/06/2023] Open
Abstract
Glioma is characterized as the most aggressive brain tumor that occurred in the central nervous system. The circadian rhythm is an essential cyclic change system generated by the endogenous circadian clock. Current studies found that the circadian clock affects glioma pathophysiology. It is still controversial whether the circadian rhythm disruption is a cause or an effect of tumorigenesis. This review discussed the association between cell cycle and circadian clock and provided a prominent molecular theoretical basis for tumor therapy. We illustrated the external factors affecting the circadian clock including thermodynamics, hypoxia, post-translation, and microRNA, while the internal characteristics concerning the circadian clock in glioma involve stemness, metabolism, radiotherapy sensitivity, and chemotherapy sensitivity. We also summarized the molecular pathways and the therapeutic drugs involved in the glioma circadian rhythm. There are still many questions in this field waiting for further investigation. The results of glioma chronotherapy in sensitizing radiation therapy and chemotherapy have shown great therapeutic potential in improving clinical outcomes. These findings will help us further understand the characteristics of glioma pathophysiology.
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Affiliation(s)
- Zongqi Wang
- Department of Neurosurgery & Brain and Nerve Research LaboratoryThe First Affiliated Hospital of Soochow UniversitySuzhouChina,Institute of Stroke ResearchSoochow UniversitySuzhouChina
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research LaboratoryThe First Affiliated Hospital of Soochow UniversitySuzhouChina,Institute of Stroke ResearchSoochow UniversitySuzhouChina
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11
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Abstract
Bacterial proteases are a promising post-translational regulation strategy in synthetic circuits because they recognize specific amino acid degradation tags (degrons) that can be fine-tuned to modulate the degradation levels of tagged proteins. For this reason, recent efforts have been made in the search for new degrons. Here we review the up-to-date applications of degradation tags for circuit engineering in bacteria. In particular, we pay special attention to the effects of degradation bottlenecks in synthetic oscillators and introduce mathematical approaches to study queueing that enable the quantitative modelling of proteolytic queues.
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Affiliation(s)
- Prajakta Jadhav
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, USA
| | - Yanyan Chen
- Program for Computational and Systems Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Nicholas Butzin
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, USA
| | - Javier Buceta
- Institute for Integrative Systems Biology (I2SysBio, CSIC-UV), Paterna, Valencia 46980, Spain
| | - Arantxa Urchueguía
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD, USA.,Institute for Integrative Systems Biology (I2SysBio, CSIC-UV), Paterna, Valencia 46980, Spain
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12
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Call SN, Andrews LB. CRISPR-Based Approaches for Gene Regulation in Non-Model Bacteria. Front Genome Ed 2022; 4:892304. [PMID: 35813973 PMCID: PMC9260158 DOI: 10.3389/fgeed.2022.892304] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 04/11/2022] [Indexed: 01/08/2023] Open
Abstract
CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) have become ubiquitous approaches to control gene expression in bacteria due to their simple design and effectiveness. By regulating transcription of a target gene(s), CRISPRi/a can dynamically engineer cellular metabolism, implement transcriptional regulation circuitry, or elucidate genotype-phenotype relationships from smaller targeted libraries up to whole genome-wide libraries. While CRISPRi/a has been primarily established in the model bacteria Escherichia coli and Bacillus subtilis, a growing numbering of studies have demonstrated the extension of these tools to other species of bacteria (here broadly referred to as non-model bacteria). In this mini-review, we discuss the challenges that contribute to the slower creation of CRISPRi/a tools in diverse, non-model bacteria and summarize the current state of these approaches across bacterial phyla. We find that despite the potential difficulties in establishing novel CRISPRi/a in non-model microbes, over 190 recent examples across eight bacterial phyla have been reported in the literature. Most studies have focused on tool development or used these CRISPRi/a approaches to interrogate gene function, with fewer examples applying CRISPRi/a gene regulation for metabolic engineering or high-throughput screens and selections. To date, most CRISPRi/a reports have been developed for common strains of non-model bacterial species, suggesting barriers remain to establish these genetic tools in undomesticated bacteria. More efficient and generalizable methods will help realize the immense potential of programmable CRISPR-based transcriptional control in diverse bacteria.
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Affiliation(s)
- Stephanie N. Call
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA, United States
| | - Lauren B. Andrews
- Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA, United States
- Biotechnology Training Program, University of Massachusetts Amherst, Amherst, MA, United States
- Molecular and Cellular Biology Graduate Program, University of Massachusetts Amherst, Amherst, MA, United States
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13
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Liu B, Cuba Samaniego C, Bennett M, Chappell J, Franco E. RNA Compensation: A Positive Feedback Insulation Strategy for RNA-Based Transcription Networks. ACS Synth Biol 2022; 11:1240-1250. [PMID: 35244392 DOI: 10.1021/acssynbio.1c00540] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The lack of signaling modularity of biomolecular systems poses major challenges toward engineering complex networks. Directional signaling between an upstream and a downstream circuit requires the presence of binding events, which result in the consumption of regulatory molecules and can compromise the operation of the upstream circuit. This issue has been previously addressed by introducing insulation strategies that include high-gain negative feedback and activation-deactivation reaction cycles. In this paper, we focus on RNA-based circuits and propose a new positive-feedback strategy to mitigate signal consumption that we propose occurs for each regulatory event due to irreversible binding of the RNA input to the RNA target. To mitigate this, an extra RNA input is added in tandem with transcription output to compensate the RNA consumption, leading to concentration robustness of the input RNA molecule regardless of the amount of downstream modules. We term this strategy RNA compensation, and it can be applied to systems that have a stringent input-output gain, such as Small Transcription Activating RNAs (STARs). Our theoretical analysis shows that RNA compensation not only eliminates the signaling consumption in individual STAR-based regulators, but also improves the composability of STAR cascades and the modularity of RNA bistable systems.
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Affiliation(s)
- Baiyang Liu
- Graduate Program in Systems, Synthetic, and Physical Biology, Rice University, Houston, Texas 77005, United States
| | - Christian Cuba Samaniego
- Department of Mechanical and Aerospace Engineering, Bioengineering, and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, United States
| | - Matthew Bennett
- Department of Biosciences, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | - James Chappell
- Department of Biosciences, Rice University, Houston, Texas 77005, United States
- Department of Bioengineering, Rice University, Houston, Texas 77005, United States
| | - Elisa Franco
- Department of Mechanical and Aerospace Engineering, Bioengineering, and Molecular Biology Institute, University of California at Los Angeles, Los Angeles, California 90095, United States
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Climent-Catala A, Ouldridge TE, Stan GBV, Bae W. Building an RNA-Based Toggle Switch Using Inhibitory RNA Aptamers. ACS Synth Biol 2022; 11:562-569. [PMID: 35133150 PMCID: PMC9007568 DOI: 10.1021/acssynbio.1c00580] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
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Synthetic
RNA systems offer unique advantages such as faster response,
increased specificity, and programmability compared to conventional
protein-based networks. Here, we demonstrate an in vitro RNA-based toggle switch using RNA aptamers capable of inhibiting
the transcriptional activity of T7 or SP6 RNA polymerases. The activities
of both polymerases are monitored simultaneously by using Broccoli
and malachite green light-up aptamer systems. In our toggle switch,
a T7 promoter drives the expression of SP6 inhibitory aptamers, and
an SP6 promoter expresses T7 inhibitory aptamers. We show that the
two distinct states originating from the mutual inhibition of aptamers
can be toggled by adding DNA sequences to sequester the RNA inhibitory
aptamers. Finally, we assessed our RNA-based toggle switch in degrading
conditions by introducing controlled degradation of RNAs using a mix
of RNases. Our results demonstrate that the RNA-based toggle switch
could be used as a control element for nucleic acid networks in synthetic
biology applications.
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Affiliation(s)
- Alicia Climent-Catala
- Imperial College Centre for Synthetic Biology, London, SW7 2AZ, U.K
- Department of Chemistry, Imperial College London, London, SW7 2AZ, U.K
| | - Thomas E. Ouldridge
- Imperial College Centre for Synthetic Biology, London, SW7 2AZ, U.K
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, U.K
| | - Guy-Bart V. Stan
- Imperial College Centre for Synthetic Biology, London, SW7 2AZ, U.K
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, U.K
| | - Wooli Bae
- Imperial College Centre for Synthetic Biology, London, SW7 2AZ, U.K
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, U.K
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15
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CRISPR-Based Genetic Switches and Other Complex Circuits: Research and Application. Life (Basel) 2021; 11:life11111255. [PMID: 34833131 PMCID: PMC8621321 DOI: 10.3390/life11111255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 12/26/2022] Open
Abstract
CRISPR-based enzymes have offered a unique capability to the design of genetic switches, with advantages in designability, modularity and orthogonality. CRISPR-based genetic switches operate on multiple levels of life, including transcription and translation. In both prokaryotic and eukaryotic cells, deactivated CRISPR endonuclease and endoribonuclease have served in genetic switches for activating or repressing gene expression, at both transcriptional and translational levels. With these genetic switches, more complex circuits have been assembled to achieve sophisticated functions including inducible switches, non-linear response and logical biocomputation. As more CRISPR enzymes continue to be excavated, CRISPR-based genetic switches will be used in a much wider range of applications.
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Tietze L, Lale R. Importance of the 5' regulatory region to bacterial synthetic biology applications. Microb Biotechnol 2021; 14:2291-2315. [PMID: 34171170 PMCID: PMC8601185 DOI: 10.1111/1751-7915.13868] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 01/02/2023] Open
Abstract
The field of synthetic biology is evolving at a fast pace. It is advancing beyond single-gene alterations in single hosts to the logical design of complex circuits and the development of integrated synthetic genomes. Recent breakthroughs in deep learning, which is increasingly used in de novo assembly of DNA components with predictable effects, are also aiding the discipline. Despite advances in computing, the field is still reliant on the availability of pre-characterized DNA parts, whether natural or synthetic, to regulate gene expression in bacteria and make valuable compounds. In this review, we discuss the different bacterial synthetic biology methodologies employed in the creation of 5' regulatory regions - promoters, untranslated regions and 5'-end of coding sequences. We summarize methodologies and discuss their significance for each of the functional DNA components, and highlight the key advances made in bacterial engineering by concentrating on their flaws and strengths. We end the review by outlining the issues that the discipline may face in the near future.
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Affiliation(s)
- Lisa Tietze
- PhotoSynLabDepartment of BiotechnologyFaculty of Natural SciencesNorwegian University of Science and TechnologyTrondheimN‐7491Norway
| | - Rahmi Lale
- PhotoSynLabDepartment of BiotechnologyFaculty of Natural SciencesNorwegian University of Science and TechnologyTrondheimN‐7491Norway
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17
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Henningsen J, Schwarz-Schilling M, Leibl A, Gutiérrez JN, Sagredo S, Simmel FC. Single Cell Characterization of a Synthetic Bacterial Clock with a Hybrid Feedback Loop Containing dCas9-sgRNA. ACS Synth Biol 2020; 9:3377-3387. [PMID: 33231079 DOI: 10.1021/acssynbio.0c00438] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Genetic networks that generate oscillations in gene expression activity are found in a wide range of organisms throughout all kingdoms of life. Oscillatory dynamics facilitates the temporal orchestration of metabolic and growth processes inside cells and organisms, as well as the synchronization of such processes with periodically occurring changes in the environment. Synthetic oscillator gene circuits such as the "repressilator" can perform similar functions in bacteria. Until recently, such circuits were mainly based on a relatively small set of well-characterized transcriptional repressors and activators. A promising, sequence-programmable alternative for gene regulation is given by CRISPR interference (CRISPRi), which enables transcriptional repression of nearly arbitrary gene targets directed by short guide RNA molecules. In order to demonstrate the use of CRISPRi in the context of dynamic gene circuits, we here replaced one of the nodes of a repressilator circuit by the RNA-guided dCas9 protein. Using single cell experiments in microfluidic reactors we show that this system displays robust relaxation oscillations over multiple periods and over several days. With a period of ≈14 bacterial generations, our oscillator is similar in speed as previously reported oscillators. Using an information-theoretic approach for the analysis of the single cell data, the potential of the circuit to act as a synthetic pacemaker for cellular processes is evaluated. We also observe that the oscillator appears to affect cellular growth, leading to variations in growth rate with the oscillator's frequency.
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Affiliation(s)
| | | | - Andreas Leibl
- Physics Department, TU Munich, D-85748 Garching, Germany
| | | | - Sandra Sagredo
- Physics Department, TU Munich, D-85748 Garching, Germany
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18
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Santos-Moreno J, Schaerli Y. CRISPR-based gene expression control for synthetic gene circuits. Biochem Soc Trans 2020; 48:1979-1993. [PMID: 32964920 PMCID: PMC7609024 DOI: 10.1042/bst20200020] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 12/22/2022]
Abstract
Synthetic gene circuits allow us to govern cell behavior in a programmable manner, which is central to almost any application aiming to harness engineered living cells for user-defined tasks. Transcription factors (TFs) constitute the 'classic' tool for synthetic circuit construction but some of their inherent constraints, such as insufficient modularity, orthogonality and programmability, limit progress in such forward-engineering endeavors. Here we review how CRISPR (clustered regularly interspaced short palindromic repeats) technology offers new and powerful possibilities for synthetic circuit design. CRISPR systems offer superior characteristics over TFs in many aspects relevant to a modular, predictable and standardized circuit design. Thus, the choice of CRISPR technology as a framework for synthetic circuit design constitutes a valid alternative to complement or replace TFs in synthetic circuits and promises the realization of more ambitious designs.
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Affiliation(s)
- Javier Santos-Moreno
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
| | - Yolanda Schaerli
- Department of Fundamental Microbiology, University of Lausanne, Biophore Building, 1015 Lausanne, Switzerland
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