1
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Rojo-Romanos T, Karpinski J, Millen S, Beschorner N, Simon F, Paszkowski-Rogacz M, Lansing F, Schneider PM, Sonntag J, Hauber J, Thoma-Kress AK, Buchholz F. Precise excision of HTLV-1 provirus with a designer-recombinase. Mol Ther 2023; 31:2266-2285. [PMID: 36934299 PMCID: PMC10362392 DOI: 10.1016/j.ymthe.2023.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 02/06/2023] [Accepted: 03/12/2023] [Indexed: 03/19/2023] Open
Abstract
The human T cell leukemia virus type 1 (HTLV-1) is a pathogenic retrovirus that persists as a provirus in the genome of infected cells and can lead to adult T cell leukemia (ATL). Worldwide, more than 10 million people are infected and approximately 5% of these individuals will develop ATL, a highly aggressive cancer that is currently incurable. In the last years, genome editing tools have emerged as promising antiviral agents. In this proof-of-concept study, we use substrate-linked directed evolution (SLiDE) to engineer Cre-derived site-specific recombinases to excise the HTLV-1 proviral genome from infected cells. We identified a conserved loxP-like sequence (loxHTLV) present in the long terminal repeats of the majority of virus isolates. After 181 cycles of SLiDE, we isolated a designer-recombinase (designated RecHTLV), which efficiently recombines the loxHTLV sequence in bacteria and human cells with high specificity. Expression of RecHTLV in human Jurkat T cells resulted in antiviral activity when challenged with an HTLV-1 infection. Moreover, expression of RecHTLV in chronically infected SP cells led to the excision of HTLV-1 proviral DNA. Our data suggest that recombinase-mediated excision of the HTLV-1 provirus represents a promising approach to reduce proviral load in HTLV-1-infected individuals, potentially preventing the development of HTLV-1-associated diseases.
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Affiliation(s)
- Teresa Rojo-Romanos
- Medical Systems Biology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
| | - Janet Karpinski
- Medical Systems Biology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
| | - Sebastian Millen
- Institute of Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Niklas Beschorner
- PROVIREX Genome Editing Therapies GmbH, Luruper Hauptstrasse 1, 22547 Hamburg, Germany
| | - Florian Simon
- Institute of Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Maciej Paszkowski-Rogacz
- Medical Systems Biology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
| | - Felix Lansing
- Medical Systems Biology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
| | - Paul Martin Schneider
- Medical Systems Biology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
| | - Jan Sonntag
- Medical Systems Biology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany
| | - Joachim Hauber
- PROVIREX Genome Editing Therapies GmbH, Luruper Hauptstrasse 1, 22547 Hamburg, Germany
| | - Andrea K Thoma-Kress
- Institute of Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Frank Buchholz
- Medical Systems Biology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technical University Dresden, 01307 Dresden, Germany.
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2
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Schmitt LT, Paszkowski-Rogacz M, Jug F, Buchholz F. Prediction of designer-recombinases for DNA editing with generative deep learning. Nat Commun 2022; 13:7966. [PMID: 36575171 PMCID: PMC9794738 DOI: 10.1038/s41467-022-35614-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022] Open
Abstract
Site-specific tyrosine-type recombinases are effective tools for genome engineering, with the first engineered variants having demonstrated therapeutic potential. So far, adaptation to new DNA target site selectivity of designer-recombinases has been achieved mostly through iterative cycles of directed molecular evolution. While effective, directed molecular evolution methods are laborious and time consuming. Here we present RecGen (Recombinase Generator), an algorithm for the intelligent generation of designer-recombinases. We gather the sequence information of over one million Cre-like recombinase sequences evolved for 89 different target sites with which we train Conditional Variational Autoencoders for recombinase generation. Experimental validation demonstrates that the algorithm can predict recombinase sequences with activity on novel target-sites, indicating that RecGen is useful to accelerate the development of future designer-recombinases.
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Affiliation(s)
- Lukas Theo Schmitt
- grid.4488.00000 0001 2111 7257Medical Systems Biology, Medical Faculty, TU Dresden, 01307 Dresden, Germany
| | - Maciej Paszkowski-Rogacz
- grid.4488.00000 0001 2111 7257Medical Systems Biology, Medical Faculty, TU Dresden, 01307 Dresden, Germany
| | - Florian Jug
- grid.510779.d0000 0004 9414 6915Fondazione Human Technopole, Milano, Italy ,grid.495510.c0000 0004 9335 670XCenter for Systems Biology Dresden, Dresden, Germany ,grid.419537.d0000 0001 2113 4567Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Frank Buchholz
- grid.4488.00000 0001 2111 7257Medical Systems Biology, Medical Faculty, TU Dresden, 01307 Dresden, Germany
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3
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Yamauchi Y, Matsukura H, Motone K, Ueda M, Aoki W. Evaluation of a library of loxP variants with a wide range of recombination efficiencies by Cre. PLoS One 2022; 17:e0276657. [PMID: 36269789 PMCID: PMC9586403 DOI: 10.1371/journal.pone.0276657] [Citation(s) in RCA: 1] [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: 07/01/2022] [Accepted: 10/11/2022] [Indexed: 11/18/2022] Open
Abstract
Sparse labeling of individual cells is an important approach in neuroscience and many other fields of research. Various methods have been developed to sparsely label only a small population of cells; however, there is no simple and reproducible strategy for managing the probability of sparse labeling at desired levels. Here, we aimed to develop a novel methodology based on the Cre-lox system to regulate sparseness at desired levels, and we purely analyzed cleavage efficiencies of loxP mutants by Cre. We hypothesized that mutations in the loxP sequence reduce the recognition efficiency by Cre, which enables the regulation of the sparseness level of gene expression. In this research, we mutagenized the loxP sequence and analyzed a library of loxP variants. We evaluated more than 1000 mutant loxP sequences, including mutants with reduced excision efficiencies by Cre ranging from 0.51% to 59%. This result suggests that these mutant loxP sequences can be useful in regulating the sparseness of genetic labeling at desired levels.
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Affiliation(s)
- Yuji Yamauchi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
- Japan Society for the Promotion of Science, Sakyo-ku, Kyoto, Japan
| | - Hidenori Matsukura
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Keisuke Motone
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, Washington, United States of America
| | - Mitsuyoshi Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Wataru Aoki
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan
- * E-mail:
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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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Voziyanova E, Li F, Shah R, Voziyanov Y. Genome targeting by hybrid Flp-TAL recombinases. Sci Rep 2020; 10:17479. [PMID: 33060660 PMCID: PMC7562724 DOI: 10.1038/s41598-020-74474-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/08/2020] [Indexed: 11/09/2022] Open
Abstract
Genome engineering is a rapidly evolving field that benefits from the availability of different tools that can be used to perform genome manipulation tasks. We describe here the development of the Flp-TAL recombinases that can target genomic FRT-like sequences in their native chromosomal locations. Flp-TAL recombinases are hybrid enzymes that are composed of two functional modules: a variant of site-specific tyrosine recombinase Flp, which can have either narrow or broad target specificity, and the DNA-binding domain of the transcription activator-like effector, TAL. In Flp-TAL, the TAL module is responsible for delivering and stabilizing the Flp module onto the desired genomic FRT-like sequence where the Flp module mediates recombination. We demonstrate the functionality of the Flp-TAL recombinases by performing integration and deletion experiments in human HEK-293 cells. In the integration experiments we targeted a vector to three genomic FRT-like sequences located in the β-globin locus. In the deletion experiments we excised ~ 15 kilobases of DNA that contained a fragment of the integrated vector sequence and the neighboring genome sequence. On average, the efficiency of the integration and deletion reactions was about 0.1% and 20%, respectively.
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Affiliation(s)
- Eugenia Voziyanova
- School of Biological Sciences, Louisiana Tech University, 1 Adams Blvd., Ruston, LA, 71272, USA
| | - Feng Li
- School of Biological Sciences, Louisiana Tech University, 1 Adams Blvd., Ruston, LA, 71272, USA
| | - Riddhi Shah
- Department of Medicine, Columbia University Medical Center, New York, NY, 10032, USA
| | - Yuri Voziyanov
- School of Biological Sciences, Louisiana Tech University, 1 Adams Blvd., Ruston, LA, 71272, USA.
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6
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DNA binding induces a cis-to- trans switch in Cre recombinase to enable intasome assembly. Proc Natl Acad Sci U S A 2020; 117:24849-24858. [PMID: 32968014 DOI: 10.1073/pnas.2011448117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mechanistic understanding of DNA recombination in the Cre-loxP system has largely been guided by crystallographic structures of tetrameric synaptic complexes. Those studies have suggested a role for protein conformational dynamics that has not been well characterized at the atomic level. We used solution nuclear magnetic resonance (NMR) spectroscopy to discover the link between intrinsic flexibility and function in Cre recombinase. Transverse relaxation-optimized spectroscopy (TROSY) NMR spectra show the N-terminal and C-terminal catalytic domains (CreNTD and CreCat) to be structurally independent. Amide 15N relaxation measurements of the CreCat domain reveal fast-timescale dynamics in most regions that exhibit conformational differences in active and inactive Cre protomers in crystallographic tetramers. However, the C-terminal helix αN, implicated in assembly of synaptic complexes and regulation of DNA cleavage activity via trans protein-protein interactions, is unexpectedly rigid in free Cre. Chemical shift perturbations and intra- and intermolecular paramagnetic relaxation enhancement (PRE) NMR data reveal an alternative autoinhibitory conformation for the αN region of free Cre, wherein it packs in cis over the protein DNA binding surface and active site. Moreover, binding to loxP DNA induces a conformational change that dislodges the C terminus, resulting in a cis-to-trans switch that is likely to enable protein-protein interactions required for assembly of recombinogenic Cre intasomes. These findings necessitate a reexamination of the mechanisms by which this widely utilized gene-editing tool selects target sites, avoids spurious DNA cleavage activity, and controls DNA recombination efficiency.
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7
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Soni A, Augsburg M, Buchholz F, Pisabarro MT. Nearest-neighbor amino acids of specificity-determining residues influence the activity of engineered Cre-type recombinases. Sci Rep 2020; 10:13985. [PMID: 32814809 PMCID: PMC7438526 DOI: 10.1038/s41598-020-70867-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 08/03/2020] [Indexed: 11/29/2022] Open
Abstract
The tyrosine-type site-specific DNA recombinase Cre recombines its target site, loxP, with high activity and specificity without cross-recombining the target sites of highly related recombinases. Understanding how Cre achieves this precision is key to be able to rationally engineer site-specific recombinases (SSRs) for genome editing applications. Previous work has revealed key residues for target site selectivity in the Cre/loxP and the related Dre/rox recombinase systems. However, enzymes in which these residues were changed to the respective counterpart only showed weak activity on the foreign target site. Here, we use molecular modeling and dynamics simulation techniques to comprehensively explore the mechanisms by which these residues determine target recognition in the context of their flanking regions in the protein-DNA interface, and we establish a structure-based rationale for the design of improved recombination activities. Our theoretical models reveal that nearest-neighbors to the specificity-determining residues are important players for enhancing SSR activity on the foreign target site. Based on the established rationale, we design new Cre variants with improved rox recombination activities, which we validate experimentally. Our work provides new insights into the target recognition mechanisms of Cre-like recombinases and represents an important step towards the rational design of SSRs for applied genome engineering.
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Affiliation(s)
- Anjali Soni
- Structural Bioinformatics, BIOTEC, TU Dresden, Tatzberg 47-51, 01307, Dresden, Germany
| | - Martina Augsburg
- University Carl Gustav Carus and Medical Faculty, UCC, Medical Systems Biology, TU Dresden, Fetscherstrasse 74, Dresden, Germany
| | - Frank Buchholz
- University Carl Gustav Carus and Medical Faculty, UCC, Medical Systems Biology, TU Dresden, Fetscherstrasse 74, Dresden, Germany
| | - M Teresa Pisabarro
- Structural Bioinformatics, BIOTEC, TU Dresden, Tatzberg 47-51, 01307, Dresden, Germany.
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8
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Mobley CB, Vechetti IJ, Valentino TR, McCarthy JJ. CORP: Using transgenic mice to study skeletal muscle physiology. J Appl Physiol (1985) 2020; 128:1227-1239. [PMID: 32105520 DOI: 10.1152/japplphysiol.00021.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The development of tissue-specific inducible transgenic mice has provided a powerful tool to study gene function and cell biology in almost any tissue of interest at any given time within the animal's life. The purpose of this review is to describe how to use two different inducible transgenic systems, the Cre-loxP system and the Tet-ON/OFF system, that can be used to study skeletal muscle physiology. Myofiber- and satellite cell-specific Cre-loxP transgenic mice are described as is how these mice can be used to knockout a gene of interest or to deplete satellite cells in adult skeletal muscle, respectively. A myofiber-specific Tet-ON system is described as is how such mice can be used to overexpress a gene of interest or to label myonuclei. How to effectively breed and genotype the transgenic mice are also described in detail. The hope is this review will provide the basic information necessary to facilitate the incorporation of tissue-specific inducible transgenic mice into a skeletal muscle research program.
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Affiliation(s)
- C Brooks Mobley
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Ivan J Vechetti
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Taylor R Valentino
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - John J McCarthy
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
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9
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Bramlett C, Jiang D, Nogalska A, Eerdeng J, Contreras J, Lu R. Clonal tracking using embedded viral barcoding and high-throughput sequencing. Nat Protoc 2020; 15:1436-1458. [PMID: 32132718 PMCID: PMC7427513 DOI: 10.1038/s41596-019-0290-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 12/21/2019] [Indexed: 11/09/2022]
Abstract
Embedded viral barcoding in combination with high-throughput sequencing is a powerful technology with which to track single-cell clones. It can provide clonal-level insights into cellular proliferation, development, differentiation, migration, and treatment efficacy. Here, we present a detailed protocol for a viral barcoding procedure that includes the creation of barcode libraries, the viral delivery of barcodes, the recovery of barcodes, and the computational analysis of barcode sequencing data. The entire procedure can be completed within a few weeks. This barcoding method requires cells to be susceptible to viral transduction. It provides high sensitivity and throughput, and enables precise quantification of cellular progeny. It is cost efficient and does not require any advanced skills. It can also be easily adapted to many types of applications, including both in vitro and in vivo experiments.
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Affiliation(s)
- Charles Bramlett
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA
| | - Du Jiang
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA
| | - Anna Nogalska
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA
| | - Jiya Eerdeng
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA
| | - Jorge Contreras
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA
| | - Rong Lu
- Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research, Keck School of Medicine, University of Southern California, Los Angeles, Los Angeles, CA, USA.
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10
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Bessen JL, Afeyan LK, Dančík V, Koblan LW, Thompson DB, Leichner C, Clemons PA, Liu DR. High-resolution specificity profiling and off-target prediction for site-specific DNA recombinases. Nat Commun 2019; 10:1937. [PMID: 31028261 PMCID: PMC6486577 DOI: 10.1038/s41467-019-09987-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/05/2019] [Indexed: 12/26/2022] Open
Abstract
The development of site-specific recombinases (SSRs) as genome editing agents is limited by the difficulty of altering their native DNA specificities. Here we describe Rec-seq, a method for revealing the DNA specificity determinants and potential off-target substrates of SSRs in a comprehensive and unbiased manner. We applied Rec-seq to characterize the DNA specificity determinants of several natural and evolved SSRs including Cre, evolved variants of Cre, and other SSR family members. Rec-seq profiling of these enzymes and mutants thereof revealed previously uncharacterized SSR interactions, including specificity determinants not evident from SSR:DNA structures. Finally, we used Rec-seq specificity profiles to predict off-target substrates of Tre and Brec1 recombinases, including endogenous human genomic sequences, and confirmed their ability to recombine these off-target sequences in human cells. These findings establish Rec-seq as a high-resolution method for rapidly characterizing the DNA specificity of recombinases with single-nucleotide resolution, and for informing their further development. The development of site-specific recombinases as genome editing tools is limited by the difficulty of altering their DNA sequence specificity. Here the authors present Rec-seq, a method for identifying specificity determinants and off-target substrates of recombinases in an unbiased manner.
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Affiliation(s)
- Jeffrey L Bessen
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02138, USA
| | - Lena K Afeyan
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02138, USA
| | - Vlado Dančík
- Chemical Biology and Therapeutics Science Program, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA
| | - Luke W Koblan
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02138, USA
| | - David B Thompson
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02138, USA
| | | | - Paul A Clemons
- Chemical Biology and Therapeutics Science Program, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA. .,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA. .,Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02138, USA.
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11
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Bogdanove AJ, Bohm A, Miller JC, Morgan RD, Stoddard BL. Engineering altered protein-DNA recognition specificity. Nucleic Acids Res 2018; 46:4845-4871. [PMID: 29718463 PMCID: PMC6007267 DOI: 10.1093/nar/gky289] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/03/2018] [Accepted: 04/06/2018] [Indexed: 02/07/2023] Open
Abstract
Protein engineering is used to generate novel protein folds and assemblages, to impart new properties and functions onto existing proteins, and to enhance our understanding of principles that govern protein structure. While such approaches can be employed to reprogram protein-protein interactions, modifying protein-DNA interactions is more difficult. This may be related to the structural features of protein-DNA interfaces, which display more charged groups, directional hydrogen bonds, ordered solvent molecules and counterions than comparable protein interfaces. Nevertheless, progress has been made in the redesign of protein-DNA specificity, much of it driven by the development of engineered enzymes for genome modification. Here, we summarize the creation of novel DNA specificities for zinc finger proteins, meganucleases, TAL effectors, recombinases and restriction endonucleases. The ease of re-engineering each system is related both to the modularity of the protein and the extent to which the proteins have evolved to be capable of readily modifying their recognition specificities in response to natural selection. The development of engineered DNA binding proteins that display an ideal combination of activity, specificity, deliverability, and outcomes is not a fully solved problem, however each of the current platforms offers unique advantages, offset by behaviors and properties requiring further study and development.
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Affiliation(s)
- Adam J Bogdanove
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - Andrew Bohm
- Sackler School of Graduate Biomedical Sciences, Tufts University, 136 Harrison Avenue, Boston, MA 02111, USA
| | - Jeffrey C Miller
- Sangamo Therapeutics Inc. 501 Canal Blvd., Richmond, CA 94804, USA
| | - Richard D Morgan
- New England Biolabs, Inc., 240 County Road, Ipswich, MA 01938, USA
| | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98019, USA
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12
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Meinke G, Karpinski J, Buchholz F, Bohm A. Crystal structure of an engineered, HIV-specific recombinase for removal of integrated proviral DNA. Nucleic Acids Res 2017; 45:9726-9740. [PMID: 28934476 PMCID: PMC5766204 DOI: 10.1093/nar/gkx603] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 07/06/2017] [Indexed: 01/07/2023] Open
Abstract
As part of the HIV infection cycle, viral DNA inserts into the genome of host cells such that the integrated DNA encoding the viral proteins is flanked by long terminal repeat (LTR) regions from the retrovirus. In an effort to develop novel genome editing techniques that safely excise HIV provirus from cells, Tre, an engineered version of Cre recombinase, was designed to target a 34-bp sequence within the HIV-1 LTR (loxLTR). The sequence targeted by Tre lacks the symmetry present in loxP, the natural DNA substrate for Cre. We report here the crystal structure of a catalytically inactive (Y324F) mutant of this engineered Tre recombinase in complex with the loxLTR DNA substrate. We also report that 17 of the 19 amino acid changes relative to Cre contribute to the altered specificity, even though many of these residues do not contact the DNA directly. We hypothesize that some mutations increase the flexibility of the Cre tetramer and that this, along with flexibility in the DNA, enable the engineered enzyme and DNA substrate to adopt complementary conformations.
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Affiliation(s)
- Gretchen Meinke
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Janet Karpinski
- Medical Systems Biology, UCC, Medical Faculty Carl Gustav Carus, TU Dresden, 01307 Dresden, Germany
| | - Frank Buchholz
- Medical Systems Biology, UCC, Medical Faculty Carl Gustav Carus, TU Dresden, 01307 Dresden, Germany,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany,German Cancer Research Center (DKFZ), Heidelberg and German Cancer Consortium (DKTK) partner site Dresden, 01307 Dresden, Germany,National Center for Tumor Diseases (NCT), University Hospital Carl Gustav Carus, TU Dresden, 01307 Dresden, Germany
| | - Andrew Bohm
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA,To whom correspondence should be addressed. Tel: +1 617 636 2994; Fax: +1 617 636 2409;
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13
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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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14
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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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15
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Pugach EK, Richmond PA, Azofeifa JG, Dowell RD, Leinwand LA. Prolonged Cre expression driven by the α-myosin heavy chain promoter can be cardiotoxic. J Mol Cell Cardiol 2015; 86:54-61. [PMID: 26141530 PMCID: PMC4558343 DOI: 10.1016/j.yjmcc.2015.06.019] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/10/2015] [Accepted: 06/24/2015] [Indexed: 12/23/2022]
Abstract
Studying the importance of genetic factors in a desired cell type or tissue necessitates the use of precise genetic tools. With the introduction of bacteriophage Cre recombinase/loxP mediated DNA editing and promoter-specific Cre expression, it is feasible to generate conditional knockout mice in which particular genes are disrupted in a cell type-specific manner in vivo. In cardiac myocytes, this is often achieved through α-myosin heavy chain promoter (αMyHC)-driven Cre expression in conjunction with a loxP-site flanked gene of interest. Recent studies in other cell types demonstrate toxicity of Cre expression through induction of DNA damage. However, it is unclear to what extent the traditionally used αMyHC-Cre line [1] may exhibit cardiotoxicity. Further, the genotype of αMyHC-Cre(+/-) is not often included as a control group in cardiac myocyte-specific knockout studies. Here we present evidence that these αMyHC-Cre(+/-) mice show molecular signs of cardiac toxicity by 3months of age and exhibit decreased cardiac function by 6months of age compared to wild-type littermates. Hearts from αMyHC-Cre(+/-) mice also display evidence of fibrosis, inflammation, and DNA damage. Interestingly, some of the early functional changes observed in αMyHC-Cre(+/-) mice are sexually dimorphic. Given the high level of Cre recombinase expression resulting from expression from the αMyHC promoter, we asked if degenerate loxP-like sites naturally exist in the mouse genome and if so, whether they are affected by Cre in the absence of canonical loxP-sites. Using a novel bioinformatics search tool, we identified 619 loxP-like sites with 4 or less mismatches to the canonical loxP-site. 227 sites overlapped with annotated genes and 55 of these genes were expressed in cardiac muscle. Expression of ~26% of the 27 genes tested was disrupted in αMyHC-Cre(+/-) mice indicating potential targeting by Cre. Taken together, these results highlight both the importance of using αMyHC-Cre mice as controls in conditional knockout studies as well as the need for a less cardiotoxic Cre driver for the field.
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Affiliation(s)
- Emily K Pugach
- University of Colorado at Boulder, Department of Molecular, Cellular, and Developmental Biology, BioFrontiers Institute, Boulder, CO 80303 USA.
| | - Phillip A Richmond
- University of Colorado at Boulder, Department of Molecular, Cellular, and Developmental Biology, BioFrontiers Institute, Boulder, CO 80303 USA.
| | - Joseph G Azofeifa
- University of Colorado at Boulder, Department of Computer Science, Boulder, CO 80303 USA.
| | - Robin D Dowell
- University of Colorado at Boulder, Department of Molecular, Cellular, and Developmental Biology, BioFrontiers Institute, Boulder, CO 80303 USA.
| | - Leslie A Leinwand
- University of Colorado at Boulder, Department of Molecular, Cellular, and Developmental Biology, BioFrontiers Institute, Boulder, CO 80303 USA.
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16
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Shah R, Li F, Voziyanova E, Voziyanov Y. Target-specific variants of Flp recombinase mediate genome engineering reactions in mammalian cells. FEBS J 2015; 282:3323-33. [PMID: 26077105 DOI: 10.1111/febs.13345] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 05/18/2015] [Accepted: 06/12/2015] [Indexed: 12/30/2022]
Abstract
Genome engineering relies on DNA-modifying enzymes that are able to locate a DNA sequence of interest and initiate a desired genome rearrangement. Currently, the field predominantly utilizes site-specific DNA nucleases that depend on the host DNA repair machinery to complete a genome modification task. We show here that genome engineering approaches that employ target-specific variants of the self-sufficient, versatile site-specific DNA recombinase Flp can be developed into promising alternatives. We demonstrate that the Flp variant evolved to recombine an FRT-like sequence, FL-IL10A, which is located upstream of the human interleukin-10 gene, and can target this sequence in the model setting of Chinese hamster ovary and human embryonic kidney 293 cells. This target-specific Flp variant is able to perform the integration reaction and, when paired with another recombinase, the dual recombinase-mediated cassette exchange reaction. The efficiency of the integration reaction in human cells can be enhanced by 'humanizing' the Flp variant gene and by adding the nuclear localization sequence to the recombinase.
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Affiliation(s)
- Riddhi Shah
- School of Biosciences, Louisiana Tech University, Ruston, LA, USA
| | - Feng Li
- School of Biosciences, Louisiana Tech University, Ruston, LA, USA
| | | | - Yuri Voziyanov
- School of Biosciences, Louisiana Tech University, Ruston, LA, USA
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17
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Abi-Ghanem J, Chusainow J, Karimova M, Spiegel C, Hofmann-Sieber H, Hauber J, Buchholz F, Pisabarro MT. Engineering of a target site-specific recombinase by a combined evolution- and structure-guided approach. Nucleic Acids Res 2012; 41:2394-403. [PMID: 23275541 PMCID: PMC3575804 DOI: 10.1093/nar/gks1308] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Site-specific recombinases (SSRs) can perform DNA rearrangements, including deletions, inversions and translocations when their naive target sequences are placed strategically into the genome of an organism. Hence, in order to employ SSRs in heterologous hosts, their target sites have to be introduced into the genome of an organism before the enzyme can be practically employed. Engineered SSRs hold great promise for biotechnology and advanced biomedical applications, as they promise to extend the usefulness of SSRs to allow efficient and specific recombination of pre-existing, natural genomic sequences. However, the generation of enzymes with desired properties remains challenging. Here, we use substrate-linked directed evolution in combination with molecular modeling to rationally engineer an efficient and specific recombinase (sTre) that readily and specifically recombines a sequence present in the HIV-1 genome. We elucidate the role of key residues implicated in the molecular recognition mechanism and we present a rationale for sTre’s enhanced specificity. Combining evolutionary and rational approaches should help in accelerating the generation of enzymes with desired properties for use in biotechnology and biomedicine.
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Affiliation(s)
- Josephine Abi-Ghanem
- Structural Bioinformatics, BIOTEC TU Dresden, Tatzberg 47-51, 01037 Dresden, Germany
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18
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A genome-wide analysis of FRT-like sequences in the human genome. PLoS One 2011; 6:e18077. [PMID: 21448289 PMCID: PMC3063242 DOI: 10.1371/journal.pone.0018077] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 02/24/2011] [Indexed: 11/19/2022] Open
Abstract
Efficient and precise genome manipulations can be achieved by the
Flp/FRT system of site-specific DNA recombination.
Applications of this system are limited, however, to cases when target sites for
Flp recombinase, FRT sites, are pre-introduced into a genome
locale of interest. To expand use of the Flp/FRT system in
genome engineering, variants of Flp recombinase can be evolved to recognize
pre-existing genomic sequences that resemble FRT and thus can
serve as recombination sites. To understand the distribution and sequence
properties of genomic FRT-like sites, we performed a
genome-wide analysis of FRT-like sites in the human genome
using the experimentally-derived parameters. Out of 642,151 identified
FRT-like sequences, 581,157 sequences were unique and
12,452 sequences had at least one exact duplicate. Duplicated
FRT-like sequences are located mostly within LINE1, but
also within LTRs of endogenous retroviruses, Alu repeats and other repetitive
DNA sequences. The unique FRT-like sequences were classified
based on the number of matches to FRT within the first four
proximal bases pairs of the Flp binding elements of FRT and the
nature of mismatched base pairs in the same region. The data obtained will be
useful for the emerging field of genome engineering.
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19
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Gelato KA, Martin SS, Liu PH, Saunders AA, Baldwin EP. Spatially directed assembly of a heterotetrameric Cre-Lox synapse restricts recombination specificity. J Mol Biol 2008; 378:653-65. [PMID: 18374357 DOI: 10.1016/j.jmb.2008.02.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 02/13/2008] [Accepted: 02/25/2008] [Indexed: 12/21/2022]
Abstract
The pseudo-fourfold homotetrameric synapse formed by Cre protein and target DNA restricts site-specific recombination to sequences containing dyad-symmetric Cre-binding repeats. Mixtures of engineered altered-specificity Cre monomers can form heterotetramers that recombine nonidentical asymmetric sequences, allowing greater flexibility for target site selection in the genome of interest. However, the variety of tetramers allowed by random subunit association increases the chances of unintended reactivity at nontarget sites. This problem can be circumvented by specifying a unique spatial arrangement of heterotetramer subunits. By reconfiguring intersubunit protein-protein contacts, we directed the assembly of two different Cre monomers, each having a distinct DNA sequence specificity, in an alternating (ABAB) configuration. This designed heterotetramer preferentially recombined a particular pair of asymmetric Lox sites over other pairs, whereas a mixture of freely associating subunits showed little bias. Alone, the engineered monomers had reduced reactivity towards both dyad-symmetric and asymmetric sites. Specificity arose because the organization of Cre-binding repeats of the preferred substrate matched the programmed arrangement of the subunits in the heterotetrameric synapse. When this "spatial matching" principle is applied, Cre-mediated recombination can be directed to asymmetric DNA sequences with greater fidelity.
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Affiliation(s)
- Kathy A Gelato
- Biochemistry and Molecular Biology Graduate Group, University of California, Davis, CA 95616, USA
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20
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Sheren J, Langer SJ, Leinwand LA. A randomized library approach to identifying functional lox site domains for the Cre recombinase. Nucleic Acids Res 2007; 35:5464-73. [PMID: 17702764 PMCID: PMC2018622 DOI: 10.1093/nar/gkm604] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The bacteriophage P1 Cre/loxP site-specific recombination system is a useful tool in a number of genetic engineering processes. The Cre recombinase has been shown to act on DNA sequences that vary considerably from that of its bacteriophage recognition sequence, loxP. However, little is known about the sequence requirements for functional lox-like sequences. In this study, we have implemented a randomized library approach to identify the sequence characteristics of functional lox site domains. We created a randomized spacer library and a randomized arm library, and then tested them for recombination in vivo and in vitro. Results from the spacer library show that, while there is great plasticity, identity between spacer pairs is the most important factor influencing function, especially in in vitro reactions. The presence of one completely randomized arm in a functional loxP recombination reaction revealed that only three wild-type loxP arms are necessary for successful recombination in Cre-expressing bacteria, and that there are nucleotide preferences at the first three and last three positions of the randomized arm for the most efficiently recombined sequences. Finally, we found that in vitro Cre recombination reactions are much more stringent for evaluating which sequences can support efficient recombination compared to the 294-CRE system.
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Affiliation(s)
- Jamie Sheren
- University of Colorado, Department of Molecular, Cellular and Developmental Biology, 347 UCB, Boulder, CO 80309-0347, USA.
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21
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Abstract
HIV-1 integrates into the host chromosome and persists as a provirus flanked by long terminal repeats (LTRs). To date, treatment regimens primarily target the virus enzymes or virus-cell fusion, but not the integrated provirus. We report here the substrate-linked protein evolution of a tailored recombinase that recognizes an asymmetric sequence within an HIV-1 LTR. This evolved recombinase efficiently excised integrated HIV proviral DNA from the genome of infected cells. Although a long way from use in the clinic, we speculate that this type of technology might be adapted in future antiretroviral therapies, among other possible uses.
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Affiliation(s)
- Indrani Sarkar
- Max-Planck-Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-01307 Dresden, Germany
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22
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Gelato KA, Martin SS, Wong S, Baldwin EP. Multiple levels of affinity-dependent DNA discrimination in Cre-LoxP recombination. Biochemistry 2006; 45:12216-26. [PMID: 17014075 PMCID: PMC2891539 DOI: 10.1021/bi0605235] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Cre recombinase residue Arg259 mediates a canonical bidentate hydrogen-bonded contact with Gua27 of its LoxP DNA substrate. Substituting Cyt8-Gua27 with the three other basepairs, to give LoxAT, LoxTA, and LoxGC, reduced Cre-mediated recombination in vitro, with the preference order of Gua27 > Ade27 approximately Thy27 >> Cyt27. While LoxAT and LoxTA exhibited 2.5-fold reduced affinity and 2.5-5-fold slower reaction rates, LoxGC was a barely functional substrate. Its maximum level of turnover was 6-fold reduced over other substrates, and it exhibited 8.5-fold reduced Cre binding and 6.3-fold slower turnover rate. With LoxP, the rate-limiting step for recombination occurs after protein-DNA complex assembly but before completion of the first strand exchange to form the Holliday junction (HJ) intermediate. With the mutant substrates, it occurs after HJ formation. Using an increased DNA-binding E262Q/E266Q "CreQQ" variant, all four substrates react more readily, but with much less difference between them, and maintained the earlier rate-limiting step. The data indicate that Cre discriminates substrates through differences in (i) concentration dependence of active complex assembly, (ii) turnover rate, and (iii) maximum yield of product at saturation, all of which are functions of the Cre-DNA binding interaction. CreQQ suppression of Lox mutant defects implies that coupling between binding and turnover involves a change in Cre subunit DNA affinities during the "conformational switch" that occurs prior to the second strand exchange. These results provide an example of how a DNA-binding enzyme can exert specificity via affinity modulation of conformational transitions that occur along its reaction pathway.
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Affiliation(s)
| | | | | | - Enoch P. Baldwin
- Corresponding author: Phone: (530) 752-1108. FAX (530) 752-3085.
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23
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Bolusani S, Ma CH, Paek A, Konieczka JH, Jayaram M, Voziyanov Y. Evolution of variants of yeast site-specific recombinase Flp that utilize native genomic sequences as recombination target sites. Nucleic Acids Res 2006; 34:5259-69. [PMID: 17003057 PMCID: PMC1635253 DOI: 10.1093/nar/gkl548] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
As a tool in directed genome manipulations, site-specific recombination is a double-edged sword. Exquisite specificity, while highly desirable, makes it imperative that the target site be first inserted at the desired genomic locale before it can be manipulated. We describe a combination of computational and experimental strategies, based on the tyrosine recombinase Flp and its target site FRT, to overcome this impediment. We document the systematic evolution of Flp variants that can utilize, in a bacterial assay, two sites from the human interleukin 10 gene, IL10, as recombination substrates. Recombination competence on an end target site is acquired via chimeric sites containing mixed sequences from FRT and the genomic locus. This is the first time that a tyrosine site-specific recombinase has been coaxed successfully to perform DNA exchange within naturally occurring sequences derived from a foreign genomic context. We demonstrate the ability of an Flp variant to mediate integration of a reporter cassette in Escherichia coli via recombination at one of the IL10-derived sites.
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Affiliation(s)
| | - Chien-Hui Ma
- Molecular Genetics and Microbiology, University of TexasAustin1 University Station A5000Austin, TX 78712-0162, USA
| | - Andrew Paek
- Molecular Genetics and Microbiology, University of TexasAustin1 University Station A5000Austin, TX 78712-0162, USA
| | - Jay H. Konieczka
- Molecular Genetics and Microbiology, University of TexasAustin1 University Station A5000Austin, TX 78712-0162, USA
- University of ArizonaLife Sciences North 458, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA
| | - Makkuni Jayaram
- Molecular Genetics and Microbiology, University of TexasAustin1 University Station A5000Austin, TX 78712-0162, USA
- To whom correspondence should be addressed. Tel: +1 318 257 5141; Fax: +1 318 257 5104;
| | - Yuri Voziyanov
- To whom correspondence should be addressed. Tel: +1 318 257 5141; Fax: +1 318 257 5104;
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24
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Saraf-Levy T, Santoro SW, Volpin H, Kushnirsky T, Eyal Y, Schultz PG, Gidoni D, Carmi N. Site-specific recombination of asymmetric lox sites mediated by a heterotetrameric Cre recombinase complex. Bioorg Med Chem 2006; 14:3081-9. [PMID: 16412655 DOI: 10.1016/j.bmc.2005.12.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2005] [Revised: 12/12/2005] [Accepted: 12/13/2005] [Indexed: 10/25/2022]
Abstract
Previous reports have demonstrated that new Cre recombinase specificities can be developed for symmetrically designed lox mutants through directed evolution. The development of Cre variants that allow the recombination of true asymmetric lox mutant sites has not yet been addressed, however. In the present study, we demonstrate that a mixture of two different site-specific Cre recombinase molecules (wt Cre and a mutant Cre) catalyzes efficient recombination between two asymmetric lox sites in vitro, presumably via formation of a functionally active heterotetrameric complex. The results may broaden the application of site-specific recombination in basic and applied research, including the custom-design of recombinases for natural, asymmetric, and lox-related target sequences present in the genome. Future applications may potentially include genomic manipulations, for example, site-specific integrations, deletions or substitutions within precise regions of the genomes of mammalians and other organisms.
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Affiliation(s)
- Talia Saraf-Levy
- Institute of Plant Sciences, A.R.O, The Volcani Center, PO Box 6, Bet-Dagan 50250, Israel
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25
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Abstract
Systematic approaches to directed evolution of proteins have been documented since the 1970s. The ability to recruit new protein functions arises from the considerable substrate ambiguity of many proteins. The substrate ambiguity of a protein can be interpreted as the evolutionary potential that allows a protein to acquire new specificities through mutation or to regain function via mutations that differ from the original protein sequence. All organisms have evolutionarily exploited this substrate ambiguity. When exploited in a laboratory under controlled mutagenesis and selection, it enables a protein to "evolve" in desired directions. One of the most effective strategies in directed protein evolution is to gradually accumulate mutations, either sequentially or by recombination, while applying selective pressure. This is typically achieved by the generation of libraries of mutants followed by efficient screening of these libraries for targeted functions and subsequent repetition of the process using improved mutants from the previous screening. Here we review some of the successful strategies in creating protein diversity and the more recent progress in directed protein evolution in a wide range of scientific disciplines and its impacts in chemical, pharmaceutical, and agricultural sciences.
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Affiliation(s)
- Ling Yuan
- Department of Plant and Soil Sciences, and Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, KY 40546, USA.
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26
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Jahnz M, Schwille P. An ultrasensitive site-specific DNA recombination assay based on dual-color fluorescence cross-correlation spectroscopy. Nucleic Acids Res 2005; 33:e60. [PMID: 15802627 PMCID: PMC1074182 DOI: 10.1093/nar/gni060] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Site-specific exchange of genetic information is mediated by DNA recombinases, such as FLP or Cre, and has become a valuable tool in modern molecular biology. The so far low number of suitable recombinating enzymes has driven current research activities towards alteration of catalytic properties, such as thermostability or recognition sequences. However, identification and analysis of new mutants requires sensitive in vitro activity assays, which traditionally are based on gel electrophoresis. Here, we describe the development of a new sensitive DNA recombination assay based on dual-color fluorescence cross-correlation spectroscopy (DC-FCCS), which works in homogenous solution and does not require any separation step such as electrophoresis. The assay was validated with unlabeled FLP recombinase and different fluorescently labeled DNA substrates containing the FLP recognition target (FRT). This strategy fulfills all requirements for possible application in high throughput screening and engineering of new site-specific DNA recombinases starting from the FLP-FRT system, and is easily adjustable to other systems like Cre/loxP.
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Affiliation(s)
| | - Petra Schwille
- To whom correspondence should be addressed. Tel: +49 351 463 40329; Fax: +49 351 463 40342;
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27
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Sauer B, McDermott J. DNA recombination with a heterospecific Cre homolog identified from comparison of the pac-c1 regions of P1-related phages. Nucleic Acids Res 2004; 32:6086-95. [PMID: 15550568 PMCID: PMC534624 DOI: 10.1093/nar/gkh941] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sequencing of the 7 kb immC region from four P1-related phages identified a novel DNA recombinase that exhibits many Cre-like characteristics, including recombination in mammalian cells, but which has a distinctly different DNA specificity. DNA sequence comparison to the P1 immC region showed that all phages had related DNA terminase, C1 repressor and DNA recombinase genes. Although these genes from phages P7, phi(w39) and p15B were highly similar to those from P1, those of phage D6 showed significant divergence. Moreover, the D6 sequence showed evidence of DNA deletion and substitution in this region relative to the other phages. Characterization of the D6 site-specific DNA recombinase (Dre) showed that it was a tyrosine recombinase closely related to the P1 Cre recombinase, but that it had a distinct DNA specificity for a 32 bp DNA site (rox). Cre and Dre are heterospecific: Cre did not catalyze recombination at rox sites and Dre did not catalyze recombination at lox sites. Like Cre, Dre catalyzed both integrative and excisive recombination and required no other phage-encoded proteins for recombination. Dre-mediated recombination in mammalian cells showed that, like Cre, no host bacterial proteins are required for efficient Dre-mediated site-specific DNA recombination.
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Affiliation(s)
- Brian Sauer
- Stowers Institute, 1000 E 50th Street, Kansas City, MO 64110, USA.
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28
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Petyuk V, McDermott J, Cook M, Sauer B. Functional mapping of Cre recombinase by pentapeptide insertional mutagenesis. J Biol Chem 2004; 279:37040-8. [PMID: 15218019 DOI: 10.1074/jbc.m406042200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cre is a site-specific recombinase from bacteriophage P1. It is a member of the tyrosine integrase family and catalyzes reciprocal recombination between specific 34-bp sites called loxP. To analyze the structure-function relationships of this enzyme, we performed large scale pentapeptide insertional mutagenesis to generate insertions of five amino acids at random positions in the protein. The high density of insertion mutations into Cre allowed us to identify an unexpected degree of functional tolerance to insertions into the 4-5 beta-hairpin and into the loop between helices J and K (both of which contact the DNA in the minor groove) and also into helix A. The phenotypes of the majority of inserts allowed us to confirm a variety of predictions made on the basis of sequence conservation, known three-dimensional structure, and proposed catalytic mechanism. In particular, most insertions into conserved regions or secondary structure elements inactivated Cre, and most insertions located in nonconserved, unstructured regions preserved Cre activity. Less expectedly, the non-conserved and poorly structured loops and linkers between helices A-B, E-F, and M-N did not tolerate insertions, thus identifying these as critical regions for recombinase activity. We purified and characterized in vitro several representatives of these "unexpected" Cre insertion mutants. The role of those regions in the recombination process is discussed.
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Affiliation(s)
- Vladislav Petyuk
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
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29
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Konieczka JH, Paek A, Jayaram M, Voziyanov Y. Recombination of Hybrid Target Sites by Binary Combinations of Flp Variants: Mutations that Foster Interprotomer Collaboration and Enlarge Substrate Tolerance. J Mol Biol 2004; 339:365-78. [PMID: 15136039 DOI: 10.1016/j.jmb.2004.03.060] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Revised: 03/18/2004] [Accepted: 03/22/2004] [Indexed: 10/26/2022]
Abstract
Strategies of directed evolution and combinatorial mutagenesis applied to the Flp site-specific recombinase have yielded recombination systems that utilize bi-specific hybrid target sites. A hybrid site is assembled from two half-sites, each harboring a distinct binding specificity. Satisfying the two specificities by a binary combination of Flp variants, while necessary, may not be sufficient to elicit recombination. We have identified amino acid substitutions that foster interprotomer collaboration between partner Flp variants to potentiate strand exchange in hybrid sites. One such substitution, A35T, acts specifically in cis with one of the two partners of a variant pair, Flp(K82M) and Flp(A35T, R281V). The same A35T mutation is also present within a group of mutations that rescue a Flp variant, Flp(Y60S), that is defective in establishing monomer-monomer interactions on the native Flp target site. Strikingly, these mutations are localized to peptide regions involved in interdomain and interprotomer interactions within the recombination complex. The same group of mutations, when transferred to the context of wild-type Flp, can relax its specificity to include non-native target sites. The hybrid Flp systems described here mimic the naturally occurring XerC/XerD recombination system that utilizes two recombinases with distinct DNA binding specificities. The ability to overcome the constraints of binding site symmetry in Flp recombination has important implications in the targeted manipulations of genomes.
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Affiliation(s)
- Jay H Konieczka
- Molecular Genetics and Microbiology, University of Texas, Austin, 1 University Station A5000, Austin, TX 78712-0162, USA
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Jayaram M, Mehta S, Uzri D, Voziyanov Y, Velmurugan S. Site-specific recombination and partitioning systems in the stable high copy propagation of the 2-micron yeast plasmid. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 77:127-72. [PMID: 15196892 DOI: 10.1016/s0079-6603(04)77004-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Makkuni Jayaram
- Section of Molecular Genetics and Microbiology, University of Texas at Austin, Austin, TX 78712, USA
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Baldwin EP, Martin SS, Abel J, Gelato KA, Kim H, Schultz PG, Santoro SW. A Specificity Switch in Selected Cre Recombinase Variants Is Mediated by Macromolecular Plasticity and Water. ACTA ACUST UNITED AC 2003; 10:1085-94. [PMID: 14652076 PMCID: PMC2891429 DOI: 10.1016/j.chembiol.2003.10.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The basis for the altered DNA specificities of two Cre recombinase variants, obtained by mutation and selection, was revealed by their cocrystal structures. The proteins share similar substitutions but differ in their preferences for the natural LoxP substrate and an engineered substrate that is inactive with wild-type Cre, LoxM7. One variant preferentially recombines LoxM7 and contacts the substituted bases through a hydrated network of novel interlocking protein-DNA contacts. The other variant recognizes both LoxP and LoxM7 utilizing the same DNA backbone contact but different base contacts, facilitated by an unexpected DNA shift. Assisted by water, novel interaction networks can arise from few protein substitutions, suggesting how new DNA binding specificities might evolve. The contributions of macromolecular plasticity and water networks in specific DNA recognition observed here present a challenge for predictive schemes.
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Affiliation(s)
- Enoch P Baldwin
- Section of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA.
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Rowe LA, Geddie ML, Alexander OB, Matsumura I. A comparison of directed evolution approaches using the beta-glucuronidase model system. J Mol Biol 2003; 332:851-60. [PMID: 12972256 DOI: 10.1016/s0022-2836(03)00972-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Protein engineers can alter the properties of enzymes by directing their evolution in vitro. Many methods to generate molecular diversity and to identify improved clones have been developed, but experimental evolution remains as much an art as a science. We previously used DNA shuffling (sexual recombination) and a histochemical screen to direct the evolution of Escherichia coli beta-glucuronidase (GUS) variants with improved beta-galactosidase (BGAL) activity. Here, we employ the same model evolutionary system to test the efficiencies of several other techniques: recursive random mutagenesis (asexual), combinatorial cassette mutagenesis (high-frequency recombination) and a versatile high-throughput microplate screen. GUS variants with altered specificity evolved in each trial, but different combinations of mutagenesis and screening techniques effected the fixation of different beneficial mutations. The new microplate screen identified a broader set of mutations than the previously employed X-gal colony screen. Recursive random mutagenesis produced essentially asexual populations, within which beneficial mutations drove each other into extinction (clonal interference); DNA shuffling and combinatorial cassette mutagenesis led instead to the accumulation of beneficial mutations within a single allele. These results explain why recombinational approaches generally increase the efficiency of laboratory evolution.
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Affiliation(s)
- Lori A Rowe
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
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Collins CH, Yokobayashi Y, Umeno D, Arnold FH. Engineering proteins that bind, move, make and break DNA. Curr Opin Biotechnol 2003; 14:371-8. [PMID: 12943845 DOI: 10.1016/s0958-1669(03)00091-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Recent protein engineering efforts have generated artificial transcription factors that bind new target DNA sequences and enzymes that modify DNA at new target sites. Zinc-finger-based transcription factors are favored targets for design; important technological advances in their construction and numerous biotechnological applications have been reported. Other notable advances include the generation of endonucleases and recombinases with altered specificities, made by innovative combinatorial and evolutionary protein engineering strategies. An unexpectedly high tolerance to mutation in the active sites of DNA polymerases is being exploited to engineer polymerases to incorporate artificial nucleotides or to display other, nonnatural activities.
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Affiliation(s)
- Cynthia H Collins
- Biochemistry and Molecular Biophysics, California Institute of Technology, mail code 210-41, Pasadena, California 91125, USA
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Martin SS, Chu VC, Baldwin E. Modulation of the active complex assembly and turnover rate by protein-DNA interactions in Cre-LoxP recombination. Biochemistry 2003; 42:6814-26. [PMID: 12779336 PMCID: PMC2885442 DOI: 10.1021/bi0272306] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cre promotes recombination at the 34 bp LoxP sequence. Substitution of a critical C-G base pair in LoxP with an A-T base pair, to give LoxAT, reduced Cre binding in vitro and abolished recombination in vivo [Hartung, M., and Kisters-Woike, B. (1998) J. Biol. Chem. 273, 22884-22891].We demonstrated that LoxAT can be recombined in vitro. However, Cre discriminates against this substrate both before and after DNA binding. The preference for LoxP over LoxAT is the result of reduced binding and a slower turnover rate, amplified by changes in cooperativity of complex assembly. With LoxAT, similar levels of substrate turnover required 2-2.5-fold higher protein-DNA concentrations compared to LoxP, but the sigmoidal behavior of the concentration dependence was more pronounced. Further, the Cre-LoxAT complexes reacted 4-5-fold more slowly. In the 2.3 A resolution Cre-LoxAT complex structure, the major groove Arg259-guanine interaction was disrupted, explaining the reduced binding. Overall structural shifts and mobility changes indicate more favorable interactions between subunits, providing a hypothesis for the reduced turnover rate. Concomitant with the displacement of Arg259 from the DNA, adjacent charged residues Glu262 and Glu266 shifted to form salt bridges with the Arg259 guanidinium moiety. Substitution of Glu262 and Glu266 with glutamine increased Cre complex assembly efficiency and reaction rates with both LoxAT and LoxP, but diminished Cre's ability to distinguish them. The increased rate of this variant suggests that DNA substrate binding and turnover are coupled. The improved efficiency, made at some expense of sequence discrimination, may be useful for enhancing recombination in vivo.
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Affiliation(s)
- Shelley S. Martin
- Section of Molecular and Cellular Biology, University of California, 1 Shields Avenue, Davis, California 95616
| | - Victor C. Chu
- Section of Molecular and Cellular Biology, University of California, 1 Shields Avenue, Davis, California 95616
| | - Enoch Baldwin
- Section of Molecular and Cellular Biology, University of California, 1 Shields Avenue, Davis, California 95616
- Department of Chemistry, University of California, 1 Shields Avenue, Davis, California 95616
- To whom correspondence should be addressed. . Phone: (530) 752-1108. Fax: (530) 752-3085
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Voziyanov Y, Konieczka JH, Stewart AF, Jayaram M. Stepwise manipulation of DNA specificity in Flp recombinase: progressively adapting Flp to individual and combinatorial mutations in its target site. J Mol Biol 2003; 326:65-76. [PMID: 12547191 DOI: 10.1016/s0022-2836(02)01364-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Flp protein from Saccharomyces cerevisiae is one of the site-specific tyrosine family recombinases that are used widely in genomic engineering. As a first step towards mediating directed DNA rearrangements at non-native Flp recombination targets (mFRTs), we have evolved three separate groups of Flp variants that preferentially act on mFRTs containing substitutions at the first, seventh or both positions of the Flp-binding elements. The variants that recombine the double-mutant mFRT contain a subset of the mutations present in those that are active on the single-mutant mFRTs, plus additional mutations. Specificity for and discrimination between target sites, effected primarily by amino acid residues that contact DNA, can be modulated by those that do not interact with DNA or with a DNA-contacting residue. The degree of modulation can range from relaxed DNA specificity to almost completely altered specificity. Our results suggest that combined DNA shuffling and mutagenesis of libraries of Flp variants active on distinct mFRTs can yield variants that can recombine mFRTs containing combinations of the individual mutations.
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Affiliation(s)
- Yuri Voziyanov
- Section of Molecular Genetics and Microbiology, University of Texas, Austin, TX 78712-1095, USA.
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Rüfer A, Neuenschwander PF, Sauer B. Analysis of Cre-loxP interaction by surface plasmon resonance: influence of spermidine on cooperativity. Anal Biochem 2002; 308:90-9. [PMID: 12234468 DOI: 10.1016/s0003-2697(02)00247-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
To study target site selectivity of one important class of DNA-binding proteins, site-specific DNA recombinases, we developed an automated real-time kinetic assay based on surface plasmon resonance (BIACORE) and formulated a curve-fitting model that takes into account cooperative interactions. Monitoring the interaction between the Cre DNA recombinase and its specific target site loxP by BIACORE, we found that Cre associates with loxP tightly and highly cooperatively. We observed that the cooperative moment of the Cre-loxP interaction is strongly dependent on the concentration of spermidine, a small polyamine influencing DNA conformation. Thus, DNA conformation can have a profound impact on substrate recognition and subsequent recombination.
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Affiliation(s)
- Andreas Rüfer
- Oklahoma Medical Research Foundation, Oklahoma City 73104, USA
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