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Joyeux M. Tethered Particle Motion Technique in Crowded Media: Compaction of DNA by Globular Macromolecules. J Phys Chem B 2024; 128:7227-7236. [PMID: 38986040 DOI: 10.1021/acs.jpcb.4c03033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
Tethered Particle Motion (TPM) is a single molecule technique, which consists in tracking the motion of a nanoparticle (NP) immersed in a fluid and tethered to a glass surface by a DNA molecule. The present work addresses the question of the applicability of TPM to fluids which contain crowders at volume fractions ranging from that of the nucleoid of living bacteria (around 30%) up to the jamming threshold (around 66%). In particular, we were interested in determining whether TPM can be used to characterize the compaction of DNA by globular crowders. To this end, extensive Brownian Dynamics simulations were performed with a specifically built coarse-grained model. Analysis of the simulations reveals several effects not observed in dilute media, which impose constraints on the TPM setup. In particular, the Tethered Fluorophore Motion (TFM) technique, which consists in replacing the NP by a much smaller fluorophore, is probably better suited than standard TPM. Moreover, a sample preparation technique which does not involve hydrophilic patches may be required. Finally, the use of a DNA brush may be needed to achieve DNA concentrations close to in vivo ones.
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Affiliation(s)
- Marc Joyeux
- Laboratoire Interdisciplinaire de Physique, CNRS and Université Grenoble Alpes, 38400 St Martin d'Hères, France
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2
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Foster MP, Benedek MJ, Billings TD, Montgomery JS. Dynamics in Cre-loxP site-specific recombination. Curr Opin Struct Biol 2024; 88:102878. [PMID: 39029281 DOI: 10.1016/j.sbi.2024.102878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2024] [Revised: 06/15/2024] [Accepted: 06/17/2024] [Indexed: 07/21/2024]
Abstract
Cre recombinase is a phage-derived enzyme that has found utility for precise manipulation of DNA sequences. Cre recognizes and recombines pairs of loxP sequences characterized by an inverted repeat and asymmetric spacer. Cre cleaves and religates its DNA targets such that error-prone repair pathways are not required to generate intact DNA products. Major obstacles to broader applications are lack of knowledge of how Cre recognizes its targets, and how its activity is controlled. The picture emerging from high resolution methods is that the dynamic properties of both the enzyme and its DNA target are important determinants of its activity in both sequence recognition and DNA cleavage. Improved understanding of the role of dynamics in the key steps along the pathway of Cre-loxP recombination should significantly advance our ability to both redirect Cre to new sequences and to control its DNA cleavage activity in the test tube and in cells.
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Affiliation(s)
- Mark P Foster
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.
| | - Matthew J Benedek
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Tyler D Billings
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Jonathan S Montgomery
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
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3
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Zhu N, Smallwood PM, Rattner A, Chang TH, Williams J, Wang Y, Nathans J. Utility of protein-protein binding surfaces composed of anti-parallel alpha-helices and beta-sheets selected by phage display. J Biol Chem 2024; 300:107283. [PMID: 38608728 PMCID: PMC11107207 DOI: 10.1016/j.jbc.2024.107283] [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: 02/02/2024] [Revised: 04/03/2024] [Accepted: 04/05/2024] [Indexed: 04/14/2024] Open
Abstract
Over the past 3 decades, a diverse collection of small protein domains have been used as scaffolds to generate general purpose protein-binding reagents using a variety of protein display and enrichment technologies. To expand the repertoire of scaffolds and protein surfaces that might serve this purpose, we have explored the utility of (i) a pair of anti-parallel alpha-helices in a small highly disulfide-bonded 4-helix bundle, the CC4 domain from reversion-inducing Cysteine-rich Protein with Kazal Motifs and (ii) a concave beta-sheet surface and two adjacent loops in the human FN3 domain, the scaffold for the widely used monobody platform. Using M13 phage display and next generation sequencing, we observe that, in both systems, libraries of ∼30 million variants contain binding proteins with affinities in the low μM range for baits corresponding to the extracellular domains of multiple mammalian proteins. CC4- and FN3-based binding proteins were fused to the N- and/or C-termini of Fc domains and used for immunostaining of transfected cells. Additionally, FN3-based binding proteins were inserted into VP1 of AAV to direct AAV infection to cells expressing a defined surface receptor. Finally, FN3-based binding proteins were inserted into the Pvc13 tail fiber protein of an extracellular contractile injection system particle to direct protein cargo delivery to cells expressing a defined surface receptor. These experiments support the utility of CC4 helices B and C and of FN3 beta-strands C, D, and F together with adjacent loops CD and FG as surfaces for engineering general purpose protein-binding reagents.
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Affiliation(s)
- Ningyu Zhu
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Philip M Smallwood
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Amir Rattner
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Tao-Hsin Chang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - John Williams
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Yanshu Wang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA; Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, USA.
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4
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Stachowski K, Norris AS, Potter D, Wysocki VH, Foster MP. Mechanisms of Cre recombinase synaptic complex assembly and activation illuminated by Cryo-EM. Nucleic Acids Res 2022; 50:1753-1769. [PMID: 35104890 PMCID: PMC8860596 DOI: 10.1093/nar/gkac032] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/04/2022] [Accepted: 01/12/2022] [Indexed: 12/15/2022] Open
Abstract
Cre recombinase selectively recognizes DNA and prevents non-specific DNA cleavage through an orchestrated series of assembly intermediates. Cre recombines two loxP DNA sequences featuring a pair of palindromic recombinase binding elements and an asymmetric spacer region, by assembly of a tetrameric synaptic complex, cleavage of an opposing pair of strands, and formation of a Holliday junction intermediate. We used Cre and loxP variants to isolate the monomeric Cre-loxP (54 kDa), dimeric Cre2-loxP (110 kDa), and tetrameric Cre4-loxP2 assembly intermediates, and determined their structures using cryo-EM to resolutions of 3.9, 4.5 and 3.2 Å, respectively. Progressive and asymmetric bending of the spacer region along the assembly pathway enables formation of increasingly intimate interfaces between Cre protomers and illuminates the structural bases of biased loxP strand cleavage order and half-the-sites activity. Application of 3D variability analysis to the tetramer data reveals constrained conformational sampling along the pathway between protomer activation and Holliday junction isomerization. These findings underscore the importance of protein and DNA flexibility in Cre-mediated site selection, controlled activation of alternating protomers, the basis for biased strand cleavage order, and recombination efficiency. Such considerations may advance development of site-specific recombinases for use in gene editing applications.
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Affiliation(s)
- Kye Stachowski
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Andrew S Norris
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Devante Potter
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Mark P Foster
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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5
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Conformational dynamics promotes disordered regions from function-dispensable to essential in evolved site-specific DNA recombinases. Comput Struct Biotechnol J 2022; 20:989-1001. [PMID: 35242289 PMCID: PMC8860914 DOI: 10.1016/j.csbj.2022.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 01/11/2022] [Accepted: 01/11/2022] [Indexed: 12/11/2022] Open
Abstract
New functional regions emerging in evolution of DNA site-specific recombinase tails. Transient structural nucleation promotes function-dispensable regions to essential. Molecular dynamics reveals conformational diversity and its functional implications. Evolved disordered molecular mechanisms of N-term tails for protein stability. Structural disorder-based link between protein evolution, stability and function.
Protein intrinsically disordered regions (IDRs) play pivotal roles in molecular recognition and regulatory processes through structural disorder-to-order transitions. To understand and exploit the distinctive functional implications of IDRs and to unravel the underlying molecular mechanisms, structural disorder-to-function relationships need to be deciphered. The DNA site-specific recombinase system Cre/loxP represents an attractive model to investigate functional molecular mechanisms of IDRs. Cre contains a functionally dispensable disordered N-terminal tail, which becomes indispensable in the evolved Tre/loxLTR recombinase system. The difficulty to experimentally obtain structural information about this tail has so far precluded any mechanistic study on its involvement in DNA recombination. Here, we use in vitro and in silico evolution data, conformational dynamics, AI-based folding simulations, thermodynamic stability calculations, mutagenesis and DNA recombination assays to investigate how evolution and the dynamic behavior of this IDR may determine distinct functional properties. Our studies suggest that partial conformational order in the N-terminal tail of Tre recombinase and its packing to a conserved hydrophobic surface on the protein provide thermodynamic stability. Based on our results, we propose a link between protein stability and function, offering new plausible atom-detailed mechanistic insights into disorder-function relationships. Our work highlights the potential of N-terminal tails to be exploited for regulation of the activity of Cre-like tyrosine-type SSRs, which merits future investigations and could be of relevance in future rational engineering for their use in biotechnology and genomic medicine.
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Park J, Lim JM, Jung I, Heo SJ, Park J, Chang Y, Kim HK, Jung D, Yu JH, Min S, Yoon S, Cho SR, Park T, Kim HH. Recording of elapsed time and temporal information about biological events using Cas9. Cell 2021; 184:1047-1063.e23. [PMID: 33539780 DOI: 10.1016/j.cell.2021.01.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/08/2020] [Accepted: 01/12/2021] [Indexed: 01/14/2023]
Abstract
DNA has not been utilized to record temporal information, although DNA has been used to record biological information and to compute mathematical problems. Here, we found that indel generation by Cas9 and guide RNA can occur at steady rates, in contrast to typical dynamic biological reactions, and the accumulated indel frequency can be a function of time. By measuring indel frequencies, we developed a method for recording and measuring absolute time periods over hours to weeks in mammalian cells. These time-recordings were conducted in several cell types, with different promoters and delivery vectors for Cas9, and in both cultured cells and cells of living mice. As applications, we recorded the duration of chemical exposure and the lengths of elapsed time since the onset of biological events (e.g., heat exposure and inflammation). We propose that our systems could serve as synthetic "DNA clocks."
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Affiliation(s)
- Jihye Park
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 Plus Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Jung Min Lim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Inkyung Jung
- Division of Biostatistics, Department of Biomedical Systems Informatics, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Department of Biostatistics and Computing, Graduate School, Yonsei University, Seoul 03722, Republic of Korea
| | - Seok-Jae Heo
- Division of Biostatistics, Department of Biomedical Systems Informatics, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Department of Biostatistics and Computing, Graduate School, Yonsei University, Seoul 03722, Republic of Korea
| | - Jinman Park
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 Plus Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Yoojin Chang
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 Plus Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Hui Kwon Kim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 Plus Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Dongmin Jung
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Ji Hea Yu
- Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul 03722, South Korea
| | - Seonwoo Min
- Electrical and Computer Engineering, Seoul National University, Seoul 00826, Republic of Korea
| | - Sungroh Yoon
- Electrical and Computer Engineering, Seoul National University, Seoul 00826, Republic of Korea; Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 00826, Republic of Korea; Interdisciplinary Program in Artificial Intelligence, Seoul National University, Seoul 00826, Republic of Korea
| | - Sung-Rae Cho
- Brain Korea 21 Plus Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul 03722, South Korea
| | - Taeyoung Park
- Department of Applied Statistics, Yonsei University, Seoul 03722, Republic of Korea; Department of Statistics and Data Science, Yonsei University, Seoul 03722, Republic of Korea
| | - Hyongbum Henry Kim
- Department of Pharmacology, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Brain Korea 21 Plus Project for Medical Sciences, Yonsei University College of Medicine, Seoul 03722, Republic of Korea; Center for Nanomedicine, Institute for Basic Science (IBS), Seoul, Republic of Korea; Graduate Program of Nano Biomedical Engineering (NanoBME), Advanced Science Institute, Yonsei University, Seoul, Republic of Korea; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul 03722, Republic of Korea.
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7
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Fan HF, Su BY, Ma CH, Rowley PA, Jayaram M. A bipartite thermodynamic-kinetic contribution by an activating mutation to RDF-independent excision by a phage serine integrase. Nucleic Acids Res 2020; 48:6413-6430. [PMID: 32479633 PMCID: PMC7337939 DOI: 10.1093/nar/gkaa401] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/02/2020] [Accepted: 05/08/2020] [Indexed: 12/11/2022] Open
Abstract
Streptomyces phage ϕC31 integrase (Int)—a large serine site-specific recombinase—is autonomous for phage integration (attP x attB recombination) but is dependent on the phage coded gp3, a recombination directionality factor (RDF), for prophage excision (attL x attR recombination). A previously described activating mutation, E449K, induces Int to perform attL x attR recombination in the absence of gp3, albeit with lower efficiency. E449K has no adverse effect on the competence of Int for attP x attB recombination. Int(E449K) resembles Int in gp3 mediated stimulation of attL x attR recombination and inhibition of attP x attB recombination. Using single-molecule analyses, we examined the mechanism by which E449K activates Int for gp3-independent attL x attR recombination. The contribution of E449K is both thermodynamic and kinetic. First, the mutation modulates the relative abundance of Int bound attL-attR site complexes, favoring pre-synaptic (PS) complexes over non-productively bound complexes. Roughly half of the synaptic complexes formed from Int(E449K) pre-synaptic complexes are recombination competent. By contrast, Int yields only inactive synapses. Second, E449K accelerates the dissociation of non-productively bound complexes and inactive synaptic complexes formed by Int. The extra opportunities afforded to Int(E499K) in reattempting synapse formation enhances the probability of success at fruitful synapsis.
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Affiliation(s)
- Hsiu-Fang Fan
- Institute of Medical Science and Technology, National Sun Yat-sen University, Sizihwan, Kaohsiung 804, Taiwan.,Department of Chemistry, National Sun Yat-sen University, Sizihwan, Kaohsiung 804, Taiwan.,Aerosol Science Research Center, National Sun Yat-sen University, Sizihwan, Kaohsiung 804, Taiwan
| | - Bo-Yu Su
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan
| | - Chien-Hui Ma
- Department of Molecular Biosciences, UT Austin, Austin, TX 78712, USA
| | - Paul A Rowley
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Makkuni Jayaram
- Department of Molecular Biosciences, UT Austin, Austin, TX 78712, USA
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8
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Shoura MJ, Giovan SM, Vetcher AA, Ziraldo R, Hanke A, Levene SD. Loop-closure kinetics reveal a stable, right-handed DNA intermediate in Cre recombination. Nucleic Acids Res 2020; 48:4371-4381. [PMID: 32182357 PMCID: PMC7192630 DOI: 10.1093/nar/gkaa153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 02/24/2020] [Accepted: 02/29/2020] [Indexed: 11/12/2022] Open
Abstract
In Cre site-specific recombination, the synaptic intermediate is a recombinase homotetramer containing a pair of loxP DNA target sites. The enzyme system's strand-exchange mechanism proceeds via a Holliday-junction (HJ) intermediate; however, the geometry of DNA segments in the synapse has remained highly controversial. In particular, all crystallographic structures are consistent with an achiral, planar Holliday-junction (HJ) structure, whereas topological assays based on Cre-mediated knotting of plasmid DNAs are consistent with a right-handed chiral junction. We use the kinetics of loop closure involving closely spaced (131-151 bp) loxP sites to investigate the in-aqueo ensemble of conformations for the longest-lived looped DNA intermediate. Fitting the experimental site-spacing dependence of the loop-closure probability, J, to a statistical-mechanical theory of DNA looping provides evidence for substantial out-of-plane HJ distortion, which unequivocally stands in contrast to the square-planar intermediate geometry from Cre-loxP crystal structures and those of other int-superfamily recombinases. J measurements for an HJ-isomerization-deficient Cre mutant suggest that the apparent geometry of the wild-type complex is consistent with temporal averaging of right-handed and achiral structures. Our approach connects the static pictures provided by crystal structures and the natural dynamics of macromolecules in solution, thus advancing a more comprehensive dynamic analysis of large nucleoprotein structures and their mechanisms.
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Affiliation(s)
- Massa J Shoura
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Stefan M Giovan
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Alexandre A Vetcher
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Riccardo Ziraldo
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Andreas Hanke
- Department of Physics, University of Texas Rio Grande Valley, Brownsville, TX 78520, USA
| | - Stephen D Levene
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
- Physics, University of Texas at Dallas, Richardson, TX 75080, USA
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9
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Robb NC, Te Velthuis AJW, Fodor E, Kapanidis AN. Real-time analysis of single influenza virus replication complexes reveals large promoter-dependent differences in initiation dynamics. Nucleic Acids Res 2020; 47:6466-6477. [PMID: 31032520 PMCID: PMC6614853 DOI: 10.1093/nar/gkz313] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/15/2019] [Accepted: 04/24/2019] [Indexed: 12/24/2022] Open
Abstract
The viral RNA (vRNA) genome of influenza viruses is replicated by the RNA-dependent RNA polymerase (RNAP) via a complementary RNA (cRNA) intermediate. The vRNA promoter can adopt multiple conformations when bound by the RNAP. However, the dynamics, determinants, and biological role of these conformations are unknown; further, little is known about cRNA promoter conformations. To probe the RNA conformations adopted during initial replication, we monitored single, surface-immobilized vRNA and cRNA initiation complexes in real-time. Our results show that, while the 3′ terminus of the vRNA promoter exists in dynamic equilibrium between pre-initiation and initiation conformations, the cRNA promoter exhibited very limited dynamics. Two residues in the proximal 3′ region of the cRNA promoter (residues absent in the vRNA promoter) allowed the cRNA template strand to reach further into the active site, limiting promoter dynamics. Our results highlight promoter-dependent differences in influenza initiation mechanisms, and advance our understanding of virus replication.
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Affiliation(s)
- Nicole C Robb
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
| | - Aartjan J W Te Velthuis
- University of Cambridge, Department of Pathology, Division of Virology, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK
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10
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Statistical physics and mesoscopic modeling to interpret tethered particle motion experiments. Methods 2019; 169:57-68. [PMID: 31302177 DOI: 10.1016/j.ymeth.2019.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/11/2019] [Accepted: 07/07/2019] [Indexed: 11/22/2022] Open
Abstract
Tethered particle motion experiments are versatile single-molecule techniques enabling one to address in vitro the molecular properties of DNA and its interactions with various partners involved in genetic regulations. These techniques provide raw data such as the tracked particle amplitude of movement, from which relevant information about DNA conformations or states must be recovered. Solving this inverse problem appeals to specific theoretical tools that have been designed in the two last decades, together with the data pre-processing procedures that ought to be implemented to avoid biases inherent to these experimental techniques. These statistical tools and models are reviewed in this paper.
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11
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Duchi D, Gryte K, Robb NC, Morichaud Z, Sheppard C, Brodolin K, Wigneshweraraj S, Kapanidis AN. Conformational heterogeneity and bubble dynamics in single bacterial transcription initiation complexes. Nucleic Acids Res 2019; 46:677-688. [PMID: 29177430 PMCID: PMC5778504 DOI: 10.1093/nar/gkx1146] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 10/31/2017] [Indexed: 12/16/2022] Open
Abstract
Transcription initiation is a major step in gene regulation for all organisms. In bacteria, the promoter DNA is first recognized by RNA polymerase (RNAP) to yield an initial closed complex. This complex subsequently undergoes conformational changes resulting in DNA strand separation to form a transcription bubble and an RNAP-promoter open complex; however, the series and sequence of conformational changes, and the factors that influence them are unclear. To address the conformational landscape and transitions in transcription initiation, we applied single-molecule Förster resonance energy transfer (smFRET) on immobilized Escherichia coli transcription open complexes. Our results revealed the existence of two stable states within RNAP–DNA complexes in which the promoter DNA appears to adopt closed and partially open conformations, and we observed large-scale transitions in which the transcription bubble fluctuated between open and closed states; these transitions, which occur roughly on the 0.1 s timescale, are distinct from the millisecond-timescale dynamics previously observed within diffusing open complexes. Mutational studies indicated that the σ70 region 3.2 of the RNAP significantly affected the bubble dynamics. Our results have implications for many steps of transcription initiation, and support a bend-load-open model for the sequence of transitions leading to bubble opening during open complex formation.
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Affiliation(s)
- Diego Duchi
- Gene Machines Group, Biological Physics Research Unit, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Kristofer Gryte
- Gene Machines Group, Biological Physics Research Unit, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Nicole C Robb
- Gene Machines Group, Biological Physics Research Unit, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Zakia Morichaud
- CNRS UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
| | - Carol Sheppard
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Konstantin Brodolin
- CNRS UMR 9004, Institut de Recherche en Infectiologie de Montpellier, Université de Montpellier, 1919 route de Mende, 34293 Montpellier, France
| | | | - Achillefs N Kapanidis
- Gene Machines Group, Biological Physics Research Unit, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
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12
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Tethered multifluorophore motion reveals equilibrium transition kinetics of single DNA double helices. Proc Natl Acad Sci U S A 2018; 115:E7512-E7521. [PMID: 30037988 PMCID: PMC6094131 DOI: 10.1073/pnas.1800585115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Understanding cellular functions and dysfunctions often begins with quantifying the interactions between the binding partners involved in the processes. Learning about the kinetics of the interactions is of particular importance to understand the dynamics of cellular processes. We created a tethered multifluorophore motion assay using DNA origami that enables over 1-hour-long recordings of the statistical binding and unbinding of single pairs of biomolecules directly in equilibrium. The experimental concept is simple and the data interpretation is very direct, which makes the system easy to use for a wide variety of researchers. Due to the modularity and addressability of the DNA origami-based assay, our system may be readily adapted to study various other molecular interactions. We describe a tethered multifluorophore motion assay based on DNA origami for revealing bimolecular reaction kinetics on the single-molecule level. Molecular binding partners may be placed at user-defined positions and in user-defined stoichiometry; and binding states are read out by tracking the motion of quickly diffusing fluorescent reporter units. Multiple dyes per reporter unit enable singe-particle observation for more than 1 hour. We applied the system to study in equilibrium reversible hybridization and dissociation of complementary DNA single strands as a function of tether length, cation concentration, and sequence. We observed up to hundreds of hybridization and dissociation events per single reactant pair and could produce cumulative statistics with tens of thousands of binding and unbinding events. Because the binding partners per particle do not exchange, we could also detect subtle heterogeneity from molecule to molecule, which enabled separating data reflecting the actual target strand pair binding kinetics from falsifying influences stemming from chemically truncated oligonucleotides. Our data reflected that mainly DNA strand hybridization, but not strand dissociation, is affected by cation concentration, in agreement with previous results from different assays. We studied 8-bp-long DNA duplexes with virtually identical thermodynamic stability, but different sequences, and observed strongly differing hybridization kinetics. Complementary full-atom molecular-dynamics simulations indicated two opposing sequence-dependent phenomena: helical templating in purine-rich single strands and secondary structures. These two effects can increase or decrease, respectively, the fraction of strand collisions leading to successful nucleation events for duplex formation.
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13
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Fan HF, Ma CH, Jayaram M. Single-Molecule Tethered Particle Motion: Stepwise Analyses of Site-Specific DNA Recombination. MICROMACHINES 2018; 9:E216. [PMID: 30424148 PMCID: PMC6187709 DOI: 10.3390/mi9050216] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/25/2018] [Accepted: 04/28/2018] [Indexed: 12/17/2022]
Abstract
Tethered particle motion/microscopy (TPM) is a biophysical tool used to analyze changes in the effective length of a polymer, tethered at one end, under changing conditions. The tether length is measured indirectly by recording the Brownian motion amplitude of a bead attached to the other end. In the biological realm, DNA, whose interactions with proteins are often accompanied by apparent or real changes in length, has almost exclusively been the subject of TPM studies. TPM has been employed to study DNA bending, looping and wrapping, DNA compaction, high-order DNA⁻protein assembly, and protein translocation along DNA. Our TPM analyses have focused on tyrosine and serine site-specific recombinases. Their pre-chemical interactions with DNA cause reversible changes in DNA length, detectable by TPM. The chemical steps of recombination, depending on the substrate and the type of recombinase, may result in a permanent length change. Single molecule TPM time traces provide thermodynamic and kinetic information on each step of the recombination pathway. They reveal how mechanistically related recombinases may differ in their early commitment to recombination, reversibility of individual steps, and in the rate-limiting step of the reaction. They shed light on the pre-chemical roles of catalytic residues, and on the mechanisms by which accessory proteins regulate recombination directionality.
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Affiliation(s)
- Hsiu-Fang Fan
- Biophotonics and Molecular Imaging Center, Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan.
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115, Taiwan.
| | - Chien-Hui Ma
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
| | - Makkuni Jayaram
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
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14
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Tardin C. The mechanics of DNA loops bridged by proteins unveiled by single-molecule experiments. Biochimie 2017; 142:80-92. [PMID: 28804000 DOI: 10.1016/j.biochi.2017.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/06/2017] [Indexed: 12/28/2022]
Abstract
Protein-induced DNA bridging and looping is a common mechanism for various and essential processes in bacterial chromosomes. This mechanism is preserved despite the very different bacterial conditions and their expected influence on the thermodynamic and kinetic characteristics of the bridge formation and stability. Over the last two decades, single-molecule techniques carried out on in vitro DNA systems have yielded valuable results which, in combination with theoretical works, have clarified the effects of different parameters of nucleoprotein complexes on the protein-induced DNA bridging and looping process. In this review, I will outline the features that can be measured for such processes with various single-molecule techniques in use in the field. I will then describe both the experimental results and the theoretical models that illuminate the contribution of the DNA molecule itself as well as that of the bridging proteins in the DNA looping mechanism at play in the nucleoid of E. coli.
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Affiliation(s)
- Catherine Tardin
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, France.
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15
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Optimal Background Estimators in Single-Molecule FRET Microscopy. Biophys J 2017; 111:1278-1286. [PMID: 27653486 DOI: 10.1016/j.bpj.2016.07.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 06/21/2016] [Accepted: 07/26/2016] [Indexed: 11/23/2022] Open
Abstract
Single-molecule total internal reflection fluorescence (TIRF) microscopy constitutes an umbrella of powerful tools that facilitate direct observation of the biophysical properties, population heterogeneities, and interactions of single biomolecules without the need for ensemble synchronization. Due to the low signal/noise ratio in single-molecule TIRF microscopy experiments, it is important to determine the local background intensity, especially when the fluorescence intensity of the molecule is used quantitatively. Here we compare and evaluate the performance of different aperture-based background estimators used particularly in single-molecule Förster resonance energy transfer. We introduce the general concept of multiaperture signatures and use this technique to demonstrate how the choice of background can affect the measured fluorescence signal considerably. A new, to our knowledge, and simple background estimator is proposed, called the local statistical percentile (LSP). We show that the LSP background estimator performs as well as current background estimators at low molecular densities and significantly better in regions of high molecular densities. The LSP background estimator is thus suited for single-particle TIRF microscopy of dense biological samples in which the intensity itself is an observable of the technique.
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16
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Fan HF, Hsieh TS, Ma CH, Jayaram M. Single-molecule analysis of ϕC31 integrase-mediated site-specific recombination by tethered particle motion. Nucleic Acids Res 2016; 44:10804-10823. [PMID: 27986956 PMCID: PMC5159548 DOI: 10.1093/nar/gkw861] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/11/2016] [Accepted: 09/22/2016] [Indexed: 11/14/2022] Open
Abstract
Serine and tyrosine site-specific recombinases (SRs and YRs, respectively) provide templates for understanding the chemical mechanisms and conformational dynamics of strand cleavage/exchange between DNA partners. Current evidence suggests a rather intriguing mechanism for serine recombination, in which one half of the cleaved synaptic complex undergoes a 180° rotation relative to the other. The 'small' and 'large' SRs contain a compact amino-terminal catalytic domain, but differ conspicuously in their carboxyl-terminal domains. So far, only one serine recombinase has been analyzed using single substrate molecules. We now utilized single-molecule tethered particle motion (TPM) to follow step-by-step recombination catalyzed by a large SR, phage ϕC31 integrase. The integrase promotes unidirectional DNA exchange between attB and attP sites to integrate the phage genome into the host chromosome. The recombination directionality factor (RDF; ϕC31 gp3) activates the excision reaction (attL × attR). From integrase-induced changes in TPM in the presence or absence of gp3, we delineated the individual steps of recombination and their kinetic features. The gp3 protein appears to regulate recombination directionality by selectively promoting or excluding active conformations of the synapse formed by specific att site partners. Our results support a 'gated rotation' of the synaptic complex between DNA cleavage and joining.
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Affiliation(s)
- Hsiu-Fang Fan
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, 112, Taiwan
- Biophotonics and Molecular Imaging Research Center, National Yang-Ming University, 112, Taiwan
| | - Tao-Shih Hsieh
- Institute of Cellular and Organismic Biology Academia Sinica, 115, Taiwan
| | - Chien-Hui Ma
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Makkuni Jayaram
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
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17
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Abstract
Cre-lox of bacteriophage P1 has become one of the most widely used tools for genetic engineering in eukaryotes. The origins of this tool date to more than 30 years ago when Nat L. Sternberg discovered the recombinase, Cre, and its specific locus of crossover, lox, while studying the maintenance of bacteriophage P1 as a stable plasmid. Recombinations mediated by Cre assist in cyclization of the DNA of infecting phage and in resolution of prophage multimers created by generalized recombination. Early in vitro work demonstrated that, although it shares similarities with the well-characterized bacteriophage λ integration, Cre-lox is in many ways far simpler in its requirements for carrying out recombination. These features would prove critical for its development as a powerful and versatile tool in genetic engineering. We review the history of the discovery and characterization of Cre-lox and touch upon the present direction of Cre-lox research.
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Affiliation(s)
- Michael Yarmolinsky
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892;
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18
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Duchi D, Bauer DLV, Fernandez L, Evans G, Robb N, Hwang LC, Gryte K, Tomescu A, Zawadzki P, Morichaud Z, Brodolin K, Kapanidis AN. RNA Polymerase Pausing during Initial Transcription. Mol Cell 2016; 63:939-50. [PMID: 27618490 PMCID: PMC5031556 DOI: 10.1016/j.molcel.2016.08.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 04/12/2016] [Accepted: 08/05/2016] [Indexed: 11/11/2022]
Abstract
In bacteria, RNA polymerase (RNAP) initiates transcription by synthesizing short transcripts that are either released or extended to allow RNAP to escape from the promoter. The mechanism of initial transcription is unclear due to the presence of transient intermediates and molecular heterogeneity. Here, we studied initial transcription on a lac promoter using single-molecule fluorescence observations of DNA scrunching on immobilized transcription complexes. Our work revealed a long pause (“initiation pause,” ∼20 s) after synthesis of a 6-mer RNA; such pauses can serve as regulatory checkpoints. Region sigma 3.2, which contains a loop blocking the RNA exit channel, was a major pausing determinant. We also obtained evidence for RNA backtracking during abortive initial transcription and for additional pausing prior to escape. We summarized our work in a model for initial transcription, in which pausing is controlled by a complex set of determinants that modulate the transition from a 6- to a 7-nt RNA. E. coli RNA polymerase pauses during initial transcription at lac promoters Initiation pausing lasts for ∼20 s and occurs at the transition from 6- to 7-nt RNA Region 3.2 of σ70 is the main protein element controlling pausing Pausing is likely to be controlled further by a complex set of determinants
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Affiliation(s)
- Diego Duchi
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - David L V Bauer
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Laurent Fernandez
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Geraint Evans
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Nicole Robb
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Ling Chin Hwang
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Kristofer Gryte
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Alexandra Tomescu
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Pawel Zawadzki
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK
| | - Zakia Morichaud
- CNRS FRE 3689, Centre d'études d'agents Pathogénes et Biotechnologies pour la Santé (CPBS), 1919 route de Mende, 34293 Montpellier, France
| | - Konstantin Brodolin
- CNRS FRE 3689, Centre d'études d'agents Pathogénes et Biotechnologies pour la Santé (CPBS), 1919 route de Mende, 34293 Montpellier, France
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, UK.
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19
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Weber TS, Dukes M, Miles DC, Glaser SP, Naik SH, Duffy KR. Site-specific recombinatorics: in situ cellular barcoding with the Cre Lox system. BMC SYSTEMS BIOLOGY 2016; 10:43. [PMID: 27363727 PMCID: PMC4929723 DOI: 10.1186/s12918-016-0290-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 06/14/2016] [Indexed: 01/07/2023]
Abstract
BACKGROUND Cellular barcoding is a recently developed biotechnology tool that enables the familial identification of progeny of individual cells in vivo. In immunology, it has been used to track the burst-sizes of multiple distinct responding T cells over several adaptive immune responses. In the study of hematopoiesis, it revealed fate heterogeneity amongst phenotypically identical multipotent cells. Most existing approaches rely on ex vivo viral transduction of cells with barcodes followed by adoptive transfer into an animal, which works well for some systems, but precludes barcoding cells in their native environment such as those inside solid tissues. RESULTS With a view to overcoming this limitation, we propose a new design for a genetic barcoding construct based on the Cre Lox system that induces randomly created stable barcodes in cells in situ by exploiting inherent sequence distance constraints during site-specific recombination. We identify the cassette whose provably maximal code diversity is several orders of magnitude higher than what is attainable with previously considered Cre Lox barcoding approaches, exceeding the number of lymphocytes or hematopoietic progenitor cells in mice. CONCLUSIONS Its high diversity and in situ applicability, make the proposed Cre Lox based tagging system suitable for whole tissue or even whole animal barcoding. Moreover, it can be built using established technology.
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Affiliation(s)
- Tom S Weber
- Hamilton Institute, Maynooth University, Maynooth, Ireland
| | | | - Denise C Miles
- The Walter and Eliza Hall Institute of Medical Research & The University of Melbourne, Parkville, Melbourne, Australia
| | - Stefan P Glaser
- The Walter and Eliza Hall Institute of Medical Research & The University of Melbourne, Parkville, Melbourne, Australia
| | - Shalin H Naik
- The Walter and Eliza Hall Institute of Medical Research & The University of Melbourne, Parkville, Melbourne, Australia
| | - Ken R Duffy
- Hamilton Institute, Maynooth University, Maynooth, Ireland.
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20
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Meinke G, Bohm A, Hauber J, Pisabarro MT, Buchholz F. Cre Recombinase and Other Tyrosine Recombinases. Chem Rev 2016; 116:12785-12820. [PMID: 27163859 DOI: 10.1021/acs.chemrev.6b00077] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tyrosine-type site-specific recombinases (T-SSRs) have opened new avenues for the predictable modification of genomes as they enable precise genome editing in heterologous hosts. These enzymes are ubiquitous in eubacteria, prevalent in archaea and temperate phages, present in certain yeast strains, but barely found in higher eukaryotes. As tools they find increasing use for the generation and systematic modification of genomes in a plethora of organisms. If applied in host organisms, they enable precise DNA cleavage and ligation without the gain or loss of nucleotides. Criteria directing the choice of the most appropriate T-SSR system for genetic engineering include that, whenever possible, the recombinase should act independent of cofactors and that the target sequences should be long enough to be unique in a given genome. This review is focused on recent advancements in our mechanistic understanding of simple T-SSRs and their application in developmental and synthetic biology, as well as in biomedical research.
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Affiliation(s)
- Gretchen Meinke
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine , Boston, Massachusetts 02111, United States
| | - Andrew Bohm
- Department of Developmental, Molecular & Chemical Biology, Tufts University School of Medicine , Boston, Massachusetts 02111, United States
| | - Joachim Hauber
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology , 20251 Hamburg, Germany
| | | | - Frank Buchholz
- Medical Systems Biology, UCC, Medical Faculty Carl Gustav Carus TU Dresden , 01307 Dresden, Germany
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21
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Jiang B, Zhang R, Feng D, Wang F, Liu K, Jiang Y, Niu K, Yuan Q, Wang M, Wang H, Zhang Y, Fang X. A Tet-on and Cre-loxP Based Genetic Engineering System for Convenient Recycling of Selection Markers in Penicillium oxalicum. Front Microbiol 2016; 7:485. [PMID: 27148179 PMCID: PMC4828452 DOI: 10.3389/fmicb.2016.00485] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 03/23/2016] [Indexed: 01/15/2023] Open
Abstract
The lack of selective markers has been a key problem preventing multistep genetic engineering in filamentous fungi, particularly for industrial species such as the lignocellulose degrading Penicillium oxalicum JUA10-1(formerly named as Penicillium decumbens). To resolve this problem, we constructed a genetic manipulation system taking advantage of two established genetic systems: the Cre-loxP system and Tet-on system in P. oxalicum JUA10-1. This system is efficient and convenient. The expression of Cre recombinase was activated by doxycycline since it was controlled by Tet-on system. Using this system, two genes, ligD and bglI, were sequentially disrupted by loxP flanked ptrA. The successful application of this procedure will provide a useful tool for genetic engineering in filamentous fungi. This system will also play an important role in improving the productivity of interesting products and minimizing by-product when fermented by filamentous fungi.
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Affiliation(s)
- Baojie Jiang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Ruiqin Zhang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Dan Feng
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Fangzhong Wang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Kuimei Liu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Yi Jiang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Kangle Niu
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Quanquan Yuan
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Mingyu Wang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
| | - Hailong Wang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong UniversityJinan, China; State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong UniversityJinan, China
| | - Youming Zhang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong UniversityJinan, China; State Key Laboratory of Microbial Technology, School of Life Science, Shandong University-Helmholtz Institute of Biotechnology, Shandong UniversityJinan, China
| | - Xu Fang
- State Key Laboratory of Microbial Technology, School of Life Science, Shandong University Jinan, China
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22
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Abstract
The use of Cre recombinase to carry out conditional mutagenesis of transgenes and insert DNA cassettes into eukaryotic chromosomes is widespread. In addition to the numerous in vivo and in vitro applications that have been reported since Cre was first shown to function in yeast and mammalian cells nearly 30 years ago, the Cre-loxP system has also played an important role in understanding the mechanism of recombination by the tyrosine recombinase family of site-specific recombinases. The simplicity of this system, requiring only a single recombinase enzyme and short recombination sequences for robust activity in a variety of contexts, has been an important factor in both cases. This review discusses advances in the Cre recombinase field that have occurred over the past 12 years since the publication of Mobile DNA II. The focus is on those recent contributions that have provided new mechanistic insights into the reaction. Also discussed are modifications of Cre and/or the loxP sequence that have led to improvements in genome engineering applications.
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23
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Abstract
The fields of molecular genetics, biotechnology and synthetic biology are demanding ever more sophisticated molecular tools for programmed precise modification of cell genomic DNA and other DNA sequences. This review presents the current state of knowledge and development of one important group of DNA-modifying enzymes, the site-specific recombinases (SSRs). SSRs are Nature's 'molecular machines' for cut-and-paste editing of DNA molecules by inserting, deleting or inverting precisely defined DNA segments. We survey the SSRs that have been put to use, and the types of applications for which they are suitable. We also discuss problems associated with uses of SSRs, how these problems can be minimized, and how recombinases are being re-engineered for improved performance and novel applications.
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24
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Abstract
One of the disadvantages of circular plasmids and chromosomes is their high sensitivity to rearrangements caused by homologous recombination. Odd numbers of crossing-over occurring during or after replication of a circular replicon result in the formation of a dimeric molecule in which the two copies of the replicon are fused. If they are not converted back to monomers, the dimers of replicons may fail to correctly segregate at the time of cell division. Resolution of multimeric forms of circular plasmids and chromosomes is mediated by site-specific recombination, and the enzymes that catalyze this type of reaction fall into two families of proteins: the serine and tyrosine recombinase families. Here we give an overview of the variety of site-specific resolution systems found on circular plasmids and chromosomes.
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25
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The partitioning and copy number control systems of the selfish yeast plasmid: an optimized molecular design for stable persistence in host cells. Microbiol Spectr 2016; 2. [PMID: 25541598 DOI: 10.1128/microbiolspec.plas-0003-2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The multi-copy 2 micron plasmid of Saccharomyces cerevisiae, a resident of the nucleus, is remarkable for its high chromosome-like stability. The plasmid does not appear to contribute to the fitness of the host, nor does it impose a significant metabolic burden on the host at its steady state copy number. The plasmid may be viewed as a highly optimized selfish DNA element whose genome design is devoted entirely towards efficient replication, equal segregation and copy number maintenance. A partitioning system comprised of two plasmid coded proteins, Rep1 and Rep2, and a partitioning locus STB is responsible for equal or nearly equal segregation of plasmid molecules to mother and daughter cells. Current evidence supports a model in which the Rep-STB system promotes the physical association of the plasmid with chromosomes and thus plasmid segregation by a hitchhiking mechanism. The Flp site-specific recombination system housed by the plasmid plays a critical role in maintaining steady state plasmid copy number. A decrease in plasmid population due to rare missegregation events is rectified by plasmid amplification via a recombination induced rolling circle replication mechanism. Appropriate plasmid amplification, without runaway increase in copy number, is ensured by positive and negative regulation of FLP gene expression by plasmid coded proteins and by the control of Flp level/activity through host mediated post-translational modification(s) of Flp. The Flp system has been successfully utilized to understand mechanisms of site-specific recombination, to bring about directed genetic alterations for addressing fundamental problems in biology, and as a tool in biotechnological applications.
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26
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McGinn S, Bauer D, Brefort T, Dong L, El-Sagheer A, Elsharawy A, Evans G, Falk-Sörqvist E, Forster M, Fredriksson S, Freeman P, Freitag C, Fritzsche J, Gibson S, Gullberg M, Gut M, Heath S, Heath-Brun I, Heron AJ, Hohlbein J, Ke R, Lancaster O, Le Reste L, Maglia G, Marie R, Mauger F, Mertes F, Mignardi M, Moens L, Oostmeijer J, Out R, Pedersen JN, Persson F, Picaud V, Rotem D, Schracke N, Sengenes J, Stähler PF, Stade B, Stoddart D, Teng X, Veal CD, Zahra N, Bayley H, Beier M, Brown T, Dekker C, Ekström B, Flyvbjerg H, Franke A, Guenther S, Kapanidis AN, Kaye J, Kristensen A, Lehrach H, Mangion J, Sauer S, Schyns E, Tost J, van Helvoort JMLM, van der Zaag PJ, Tegenfeldt JO, Brookes AJ, Mir K, Nilsson M, Willcocks JP, Gut IG. New technologies for DNA analysis--a review of the READNA Project. N Biotechnol 2015; 33:311-30. [PMID: 26514324 DOI: 10.1016/j.nbt.2015.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/17/2015] [Indexed: 01/09/2023]
Abstract
The REvolutionary Approaches and Devices for Nucleic Acid analysis (READNA) project received funding from the European Commission for 41/2 years. The objectives of the project revolved around technological developments in nucleic acid analysis. The project partners have discovered, created and developed a huge body of insights into nucleic acid analysis, ranging from improvements and implementation of current technologies to the most promising sequencing technologies that constitute a 3(rd) and 4(th) generation of sequencing methods with nanopores and in situ sequencing, respectively.
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Affiliation(s)
- Steven McGinn
- CEA - Centre National de Génotypage, 2, rue Gaston Cremieux, 91057 Evry Cedex, France
| | - David Bauer
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Thomas Brefort
- Comprehensive Biomarker Center GmbH, Im Neuenheimer Feld 583, D-69120 Heidelberg, Germany
| | - Liqin Dong
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Afaf El-Sagheer
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK; Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Rd, Oxford OX1 3TA, UK; Chemistry Branch, Department of Science and Mathematics, Faculty of Petroleum and Mining Engineering, Suez University, Suez 43721, Egypt
| | - Abdou Elsharawy
- Institute of Clinical Molecular Biology, Christian-Albrechts-University (CAU), Am Botanischen Garten 11, D-24118 Kiel, Germany; Faculty of Sciences, Division of Biochemistry, Chemistry Department, Damietta University, New Damietta City, Egypt
| | - Geraint Evans
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, Parks Road, Oxford OX1 3PU, UK
| | - Elin Falk-Sörqvist
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Sweden
| | - Michael Forster
- Institute of Clinical Molecular Biology, Christian-Albrechts-University (CAU), Am Botanischen Garten 11, D-24118 Kiel, Germany
| | | | - Peter Freeman
- University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Camilla Freitag
- Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Joachim Fritzsche
- Department of Applied Physics, Chalmers University of Technology, Kemivägen 10, 412 96 Göteborg, Sweden
| | - Spencer Gibson
- University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Mats Gullberg
- Olink AB, Dag Hammarskjölds väg 52A, 752 37 Uppsala, Sweden
| | - Marta Gut
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, C/Baldiri Reixac 7, 08028 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Simon Heath
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, C/Baldiri Reixac 7, 08028 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Isabelle Heath-Brun
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, C/Baldiri Reixac 7, 08028 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Andrew J Heron
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, England, UK
| | - Johannes Hohlbein
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, Parks Road, Oxford OX1 3PU, UK
| | - Rongqin Ke
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Box 1031, Se-171 21 Solna, Sweden; Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Sweden
| | - Owen Lancaster
- University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Ludovic Le Reste
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, Parks Road, Oxford OX1 3PU, UK
| | - Giovanni Maglia
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, England, UK
| | - Rodolphe Marie
- DTU Nanotech, Oerstedsplads Building 345 East, 2800, Kongens Lyngby, Denmark
| | - Florence Mauger
- CEA - Centre National de Génotypage, 2, rue Gaston Cremieux, 91057 Evry Cedex, France
| | - Florian Mertes
- Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany
| | - Marco Mignardi
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Box 1031, Se-171 21 Solna, Sweden; Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Sweden
| | - Lotte Moens
- Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Sweden
| | | | - Ruud Out
- FlexGen BV, Galileiweg 8, 2333 BD Leiden, The Netherlands
| | | | - Fredrik Persson
- Department of Physics, University of Gothenburg, SE-412 96 Gothenburg, Sweden
| | - Vincent Picaud
- CEA-Saclay, Bât DIGITEO 565 - Pt Courrier 192, 91191 Gif-sur-Yvette Cedex, France
| | - Dvir Rotem
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, England, UK
| | - Nadine Schracke
- Comprehensive Biomarker Center GmbH, Im Neuenheimer Feld 583, D-69120 Heidelberg, Germany
| | - Jennifer Sengenes
- CEA - Centre National de Génotypage, 2, rue Gaston Cremieux, 91057 Evry Cedex, France
| | - Peer F Stähler
- Comprehensive Biomarker Center GmbH, Im Neuenheimer Feld 583, D-69120 Heidelberg, Germany
| | - Björn Stade
- Institute of Clinical Molecular Biology, Christian-Albrechts-University (CAU), Am Botanischen Garten 11, D-24118 Kiel, Germany
| | - David Stoddart
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, England, UK
| | - Xia Teng
- FlexGen BV, Galileiweg 8, 2333 BD Leiden, The Netherlands
| | - Colin D Veal
- University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Nathalie Zahra
- University of Leicester, University Road, Leicester LE1 7RH, UK
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, England, UK
| | - Markus Beier
- Comprehensive Biomarker Center GmbH, Im Neuenheimer Feld 583, D-69120 Heidelberg, Germany
| | - Tom Brown
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK; Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Rd, Oxford OX1 3TA, UK
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| | - Björn Ekström
- Olink AB, Dag Hammarskjölds väg 52A, 752 37 Uppsala, Sweden
| | - Henrik Flyvbjerg
- DTU Nanotech, Oerstedsplads Building 345 East, 2800, Kongens Lyngby, Denmark
| | - Andre Franke
- Institute of Clinical Molecular Biology, Christian-Albrechts-University (CAU), Am Botanischen Garten 11, D-24118 Kiel, Germany
| | - Simone Guenther
- Thermo Fisher Scientific Frankfurter Straße 129B, 64293 Darmstadt, Germany
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, Parks Road, Oxford OX1 3PU, UK
| | - Jane Kaye
- HeLEX - Centre for Health, Law and Emerging Technologies, Nuffield Department of Population Health, University of Oxford, Old Road Campus, Oxford OX3 7LF, UK
| | - Anders Kristensen
- DTU Nanotech, Oerstedsplads Building 345 East, 2800, Kongens Lyngby, Denmark
| | - Hans Lehrach
- Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany
| | - Jonathan Mangion
- Thermo Fisher Scientific Frankfurter Straße 129B, 64293 Darmstadt, Germany
| | - Sascha Sauer
- Max Planck Institute for Molecular Genetics, Ihnestrasse 73, 14195 Berlin, Germany
| | - Emile Schyns
- PHOTONIS France S.A.S. Avenue Roger Roncier, 19100 Brive B.P. 520, 19106 BRIVE Cedex, France
| | - Jörg Tost
- CEA - Centre National de Génotypage, 2, rue Gaston Cremieux, 91057 Evry Cedex, France
| | | | - Pieter J van der Zaag
- Philips Research Laboratories, High Tech Campus 11, 5656 AE Eindhoven, The Netherlands
| | - Jonas O Tegenfeldt
- Division of Solid State Physics and NanoLund, Lund University, Box 118, 22100 Lund, Sweden
| | | | - Kalim Mir
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Mats Nilsson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Box 1031, Se-171 21 Solna, Sweden; Department of Immunology, Genetics, and Pathology, Science for Life Laboratory, Uppsala University, Sweden
| | - James P Willcocks
- Oxford Nanopore Technologies, Edmund Cartwright House, 4 Robert Robinson Avenue, Oxford Science Park, Oxford OX4 4GA, UK
| | - Ivo G Gut
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, C/Baldiri Reixac 7, 08028 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
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27
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Tethered fluorophore motion: studying large DNA conformational changes by single-fluorophore imaging. Biophys J 2015; 107:1205-1216. [PMID: 25185556 DOI: 10.1016/j.bpj.2014.07.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 06/13/2014] [Accepted: 07/09/2014] [Indexed: 11/20/2022] Open
Abstract
We have previously introduced tethered fluorophore motion (TFM), a single-molecule fluorescence technique that monitors the effective length of a biopolymer such as DNA. TFM uses the same principles as tethered particle motion (TPM) but employs a single fluorophore in place of the bead, allowing TFM to be combined with existing fluorescence techniques on a standard fluorescence microscope. TFM has been previously been used to reveal the mechanism of two site-specific recombinase systems, Cre-loxP and XerCD-dif. In this work, we characterize TFM, focusing on the theoretical basis and potential applications of the technique. Since TFM is limited in observation time and photon count by photobleaching, we present a description of the sources of noise in TFM. Comparing this with Monte Carlo simulations and experimental data, we show that length changes of 100 bp of double-stranded DNA are readily distinguishable using TFM, making it comparable with TPM. We also show that the commonly recommended pixel size for single-molecule fluorescence approximately optimizes signal to noise for TFM experiments, thus enabling facile combination of TFM with other fluorescence techniques, such as Förster resonance energy transfer (FRET). Finally, we apply TFM to determine the polymerization rate of the Klenow fragment of DNA polymerase I, and we demonstrate its combination with FRET to observe synapsis formation by Cre using excitation by a single laser. We hope that TFM will be a useful addition to the single-molecule toolkit, providing excellent insight into protein-nucleic acid interactions.
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Assembly, translocation, and activation of XerCD-dif recombination by FtsK translocase analyzed in real-time by FRET and two-color tethered fluorophore motion. Proc Natl Acad Sci U S A 2015; 112:E5133-41. [PMID: 26324908 DOI: 10.1073/pnas.1510814112] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The FtsK dsDNA translocase functions in bacterial chromosome unlinking by activating XerCD-dif recombination in the replication terminus region. To analyze FtsK assembly and translocation, and the subsequent activation of XerCD-dif recombination, we extended the tethered fluorophore motion technique, using two spectrally distinct fluorophores to monitor two effective lengths along the same tethered DNA molecule. We observed that FtsK assembled stepwise on DNA into a single hexamer, and began translocation rapidly (∼ 0.25 s). Without extruding DNA loops, single FtsK hexamers approached XerCD-dif and resided there for ∼ 0.5 s irrespective of whether XerCD-dif was synapsed or unsynapsed. FtsK then dissociated, rather than reversing. Infrequently, FtsK activated XerCD-dif recombination when it encountered a preformed synaptic complex, and dissociated before the completion of recombination, consistent with each FtsK-XerCD-dif encounter activating only one round of recombination.
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29
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Fan HF, Cheng YS, Ma CH, Jayaram M. Single molecule TPM analysis of the catalytic pentad mutants of Cre and Flp site-specific recombinases: contributions of the pentad residues to the pre-chemical steps of recombination. Nucleic Acids Res 2015; 43:3237-55. [PMID: 25765648 PMCID: PMC4381057 DOI: 10.1093/nar/gkv114] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 02/03/2015] [Indexed: 12/18/2022] Open
Abstract
Cre and Flp site-specific recombinase variants harboring point mutations at their conserved catalytic pentad positions were characterized using single molecule tethered particle motion (TPM) analysis. The findings reveal contributions of these amino acids to the pre-chemical steps of recombination. They suggest functional differences between positionally conserved residues in how they influence recombinase-target site association and formation of ‘non-productive’, ‘pre-synaptic’ and ‘synaptic’ complexes. The most striking difference between the two systems is noted for the single conserved lysine. The pentad residues in Cre enhance commitment to recombination by kinetically favoring the formation of pre-synaptic complexes. These residues in Flp serve a similar function by promoting Flp binding to target sites, reducing non-productive binding and/or enhancing the rate of assembly of synaptic complexes. Kinetic comparisons between Cre and Flp, and between their derivatives lacking the tyrosine nucleophile, are consistent with a stronger commitment to recombination in the Flp system. The effect of target site orientation (head-to-head or head-to-tail) on the TPM behavior of synapsed DNA molecules supports the selection of anti-parallel target site alignment prior to the chemical steps. The integrity of the synapse, whose establishment/stability is fostered by strand cleavage in the case of Flp but not Cre, appears to be compromised by the pentad mutations.
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Affiliation(s)
- Hsiu-Fang Fan
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming University, Taipei 112, Taiwan
| | - Yong-Song Cheng
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming University, Taipei 112, Taiwan
| | - Chien-Hui Ma
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Makkuni Jayaram
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
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30
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Insights into the preferential order of strand exchange in the Cre/loxP recombinase system: impact of the DNA spacer flanking sequence and flexibility. J Comput Aided Mol Des 2015; 29:271-82. [DOI: 10.1007/s10822-014-9825-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
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31
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Hohlbein J, Craggs TD, Cordes T. Alternating-laser excitation: single-molecule FRET and beyond. Chem Soc Rev 2014; 43:1156-71. [PMID: 24037326 DOI: 10.1039/c3cs60233h] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The alternating-laser excitation (ALEX) scheme continues to expand the possibilities of fluorescence-based assays to study biological entities and interactions. Especially the combination of ALEX and single-molecule Förster Resonance Energy Transfer (smFRET) has been very successful as ALEX enables the sorting of fluorescently labelled species based on the number and type of fluorophores present. ALEX also provides a convenient way of accessing the correction factors necessary for determining accurate molecular distances. Here, we provide a comprehensive overview of the concept and current applications of ALEX and we explicitly discuss how to obtain fully corrected distance information across the entire FRET range. We also present new ideas for applications of ALEX which will push the limits of smFRET-based experiments in terms of temporal and spatial resolution for the study of complex biological systems.
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Affiliation(s)
- Johannes Hohlbein
- Laboratory of Biophysics, Wageningen UR, Wageningen, The Netherlands.
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32
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Farooq S, Fijen C, Hohlbein J. Studying DNA-protein interactions with single-molecule Förster resonance energy transfer. PROTOPLASMA 2014; 251:317-32. [PMID: 24374460 DOI: 10.1007/s00709-013-0596-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 12/09/2013] [Indexed: 05/21/2023]
Abstract
Single-molecule Förster resonance energy transfer (smFRET) has emerged as a powerful tool for elucidating biological structure and mechanisms on the molecular level. Here, we focus on applications of smFRET to study interactions between DNA and enzymes such as DNA and RNA polymerases. SmFRET, used as a nanoscopic ruler, allows for the detection and precise characterisation of dynamic and rarely occurring events, which are otherwise averaged out in ensemble-based experiments. In this review, we will highlight some recent developments that provide new means of studying complex biological systems either by combining smFRET with force-based techniques or by using data obtained from smFRET experiments as constrains for computer-aided modelling.
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Affiliation(s)
- Shazia Farooq
- Laboratory of Biophysics, Wageningen UR, Wageningen, The Netherlands
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33
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Suzuki Y, Endo M, Katsuda Y, Ou K, Hidaka K, Sugiyama H. DNA Origami Based Visualization System for Studying Site-Specific Recombination Events. J Am Chem Soc 2013; 136:211-8. [DOI: 10.1021/ja408656y] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Yuki Suzuki
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
- CREST, Japan Science
and Technology Corporation (JST), Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Masayuki Endo
- Institute for
Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan
- CREST, Japan Science
and Technology Corporation (JST), Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Yousuke Katsuda
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Keiyu Ou
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kumi Hidaka
- Institute for
Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hiroshi Sugiyama
- Department
of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
- Institute for
Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan
- CREST, Japan Science
and Technology Corporation (JST), Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan
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34
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Diagne CT, Salhi M, Crozat E, Salomé L, Cornet F, Rousseau P, Tardin C. TPM analyses reveal that FtsK contributes both to the assembly and the activation of the XerCD-dif recombination synapse. Nucleic Acids Res 2013; 42:1721-32. [PMID: 24214995 PMCID: PMC3919580 DOI: 10.1093/nar/gkt1024] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Circular chromosomes can form dimers during replication and failure to resolve those into monomers prevents chromosome segregation, which leads to cell death. Dimer resolution is catalysed by a highly conserved site-specific recombination system, called XerCD-dif in Escherichia coli. Recombination is activated by the DNA translocase FtsK, which is associated with the division septum, and is thought to contribute to the assembly of the XerCD-dif synapse. In our study, direct observation of the assembly of the XerCD-dif synapse, which had previously eluded other methods, was made possible by the use of Tethered Particle Motion, a single molecule approach. We show that XerC, XerD and two dif sites suffice for the assembly of XerCD-dif synapses in absence of FtsK, but lead to inactive XerCD-dif synapses. We also show that the presence of the γ domain of FtsK increases the rate of synapse formation and convert them into active synapses where recombination occurs. Our results represent the first direct observation of the formation of the XerCD-dif recombination synapse and its activation by FtsK.
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Affiliation(s)
- Cheikh Tidiane Diagne
- CNRS; IPBS (Institut de Pharmacologie et de Biologie Structurale); 205 route de Narbonne BP 64182, F-31077 Toulouse, France, Université de Toulouse; UPS; IPBS; F-31077 Toulouse, France, Université de Toulouse; UPS; LMGM (Laboratoire de Microbiologie et Génétique Moléculaires); F-31062 Toulouse, France and CNRS; LMGM; F-31062 Toulouse, France
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35
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Lu YW, Huang T, Tsai CT, Chang YY, Li HW, Hsu CH, Fan HF. Using Single-Molecule Approaches To Study Archaeal DNA-Binding Protein Alba1. Biochemistry 2013; 52:7714-22. [DOI: 10.1021/bi4010478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Yen-Wen Lu
- Department
of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, 112 Taiwan
| | - Tao Huang
- Department
of Chemistry, National Taiwan University, 106 Taiwan
| | - Cheng-Ting Tsai
- Department
of Chemistry, National Taiwan University, 106 Taiwan
| | - Yu-Yung Chang
- Department
of Agricultural Chemistry, National Taiwan University, 106 Taiwan
| | - Hung-Wen Li
- Department
of Chemistry, National Taiwan University, 106 Taiwan
| | - Chun-Hua Hsu
- Department
of Agricultural Chemistry, National Taiwan University, 106 Taiwan
- Center
for Systems Biology, National Taiwan University, 106 Taiwan
| | - Hsiu-Fang Fan
- Department
of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, 112 Taiwan
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36
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Conformational transitions during FtsK translocase activation of individual XerCD-dif recombination complexes. Proc Natl Acad Sci U S A 2013; 110:17302-7. [PMID: 24101525 DOI: 10.1073/pnas.1311065110] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Three single-molecule techniques have been used simultaneously and in tandem to track the formation in vitro of single XerCD-dif recombination complexes. We observed the arrival of the FtsK translocase at individual preformed synaptic complexes and demonstrated the conformational change that occurs during their activation. We then followed the reaction intermediate transitions as Holliday junctions formed through catalysis by XerD, isomerized, and were converted by XerC to reaction products, which then dissociated. These observations, along with the calculated intermediate lifetimes, inform the reaction mechanism, which plays a key role in chromosome unlinking in most bacteria with circular chromosomes.
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37
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Fan HF, Ma CH, Jayaram M. Real-time single-molecule tethered particle motion analysis reveals mechanistic similarities and contrasts of Flp site-specific recombinase with Cre and λ Int. Nucleic Acids Res 2013; 41:7031-47. [PMID: 23737451 PMCID: PMC3737535 DOI: 10.1093/nar/gkt424] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Flp, a tyrosine site-specific recombinase coded for by the selfish two micron plasmid of Saccharomyces cerevisiae, plays a central role in the maintenance of plasmid copy number. The Flp recombination system can be manipulated to bring about a variety of targeted DNA rearrangements in its native host and under non-native biological contexts. We have performed an exhaustive analysis of the Flp recombination pathway from start to finish by using single-molecule tethered particle motion (TPM). The recombination reaction is characterized by its early commitment and high efficiency, with only minor detraction from ‘non-productive’ and ‘wayward’ complexes. The recombination synapse is stabilized by strand cleavage, presumably by promoting the establishment of functional interfaces between adjacent Flp monomers. Formation of the Holliday junction intermediate poses a rate-limiting barrier to the overall reaction. Isomerization of the junction to the conformation favoring its resolution in the recombinant mode is not a slow step. Consistent with the completion of nearly every initiated reaction, the chemical steps of strand cleavage and exchange are not reversible during a recombination event. Our findings demonstrate similarities and differences between Flp and the mechanistically related recombinases λ Int and Cre. The commitment and directionality of Flp recombination revealed by TPM is consistent with the physiological role of Flp in amplifying plasmid DNA.
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Affiliation(s)
- Hsiu-Fang Fan
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan.
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38
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