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Martens KJA, Turkowyd B, Hohlbein J, Endesfelder U. Temporal analysis of relative distances (TARDIS) is a robust, parameter-free alternative to single-particle tracking. Nat Methods 2024; 21:1074-1081. [PMID: 38225387 DOI: 10.1038/s41592-023-02149-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 12/08/2023] [Indexed: 01/17/2024]
Abstract
In single-particle tracking, individual particles are localized and tracked over time to probe their diffusion and molecular interactions. Temporal crossing of trajectories, blinking particles, and false-positive localizations present computational challenges that have remained difficult to overcome. Here we introduce a robust, parameter-free alternative to single-particle tracking: temporal analysis of relative distances (TARDIS). In TARDIS, an all-to-all distance analysis between localizations is performed with increasing temporal shifts. These pairwise distances represent either intraparticle distances originating from the same particle, or interparticle distances originating from unrelated particles, and are fitted analytically to obtain quantitative measures on particle dynamics. We showcase that TARDIS outperforms tracking algorithms, benchmarked on simulated and experimental data of varying complexity. We further show that TARDIS performs accurately in complex conditions characterized by high particle density, strong emitter blinking or false-positive localizations, and is in fact limited by the capabilities of localization algorithms. TARDIS' robustness enables fivefold shorter measurements without loss of information.
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Affiliation(s)
- Koen J A Martens
- Institute for Microbiology and Biotechnology, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA.
- Laboratory of Biophysics, Wageningen University and Research, Wageningen, the Netherlands.
| | - Bartosz Turkowyd
- Institute for Microbiology and Biotechnology, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Johannes Hohlbein
- Laboratory of Biophysics, Wageningen University and Research, Wageningen, the Netherlands
- Microspectroscopy Research Facility, Wageningen University and Research, Wageningen, the Netherlands
| | - Ulrike Endesfelder
- Institute for Microbiology and Biotechnology, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA, USA
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Olivi L, Bagchus C, Pool V, Bekkering E, Speckner K, Offerhaus H, Wu W, Depken M, Martens KA, Staals RJ, Hohlbein J. Live-cell imaging reveals the trade-off between target search flexibility and efficiency for Cas9 and Cas12a. Nucleic Acids Res 2024; 52:5241-5256. [PMID: 38647045 PMCID: PMC11109954 DOI: 10.1093/nar/gkae283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 03/25/2024] [Accepted: 04/04/2024] [Indexed: 04/25/2024] Open
Abstract
CRISPR-Cas systems have widely been adopted as genome editing tools, with two frequently employed Cas nucleases being SpyCas9 and LbCas12a. Although both nucleases use RNA guides to find and cleave target DNA sites, the two enzymes differ in terms of protospacer-adjacent motif (PAM) requirements, guide architecture and cleavage mechanism. In the last years, rational engineering led to the creation of PAM-relaxed variants SpRYCas9 and impLbCas12a to broaden the targetable DNA space. By employing their catalytically inactive variants (dCas9/dCas12a), we quantified how the protein-specific characteristics impact the target search process. To allow quantification, we fused these nucleases to the photoactivatable fluorescent protein PAmCherry2.1 and performed single-particle tracking in cells of Escherichia coli. From our tracking analysis, we derived kinetic parameters for each nuclease with a non-targeting RNA guide, strongly suggesting that interrogation of DNA by LbdCas12a variants proceeds faster than that of SpydCas9. In the presence of a targeting RNA guide, both simulations and imaging of cells confirmed that LbdCas12a variants are faster and more efficient in finding a specific target site. Our work demonstrates the trade-off of relaxing PAM requirements in SpydCas9 and LbdCas12a using a powerful framework, which can be applied to other nucleases to quantify their DNA target search.
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Affiliation(s)
- Lorenzo Olivi
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Cleo Bagchus
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands
| | - Victor Pool
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands
| | - Ezra Bekkering
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands
| | - Konstantin Speckner
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands
| | - Hidde Offerhaus
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Wen Y Wu
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Martin Depken
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Koen J A Martens
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands
| | - Raymond H J Staals
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Johannes Hohlbein
- Laboratory of Biophysics, Wageningen University & Research, Wageningen, The Netherlands
- Microspectroscopy Research Facility, Wageningen University & Research, Wageningen, The Netherlands
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Yan D, Xue J, Xiao J, Lyu Z, Yang X. Protocol for single-molecule labeling and tracking of bacterial cell division proteins. STAR Protoc 2024; 5:102766. [PMID: 38085639 PMCID: PMC10733747 DOI: 10.1016/j.xpro.2023.102766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/11/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
Here, we present a protocol for labeling and tracking individual molecules, particularly cell division proteins in live bacterial cells. The protocol encompasses strain construction, single-molecule imaging, trajectory segmentation, and motion property analysis. The protocol enables the identification of distinctive motion states associated with different cell division proteins. Subsequent assessments of the dynamic behaviors of these proteins provide insights into their activities and interactions at the septum during cell division. For complete details on the use and execution of this protocol, please refer to Yang et al. (2021),1 Lyu et al. (2022),2 and Mahone et al. (2024).3.
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Affiliation(s)
- Di Yan
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Jinchan Xue
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Zhixin Lyu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Xinxing Yang
- School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
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