1
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Moritz L, Schon SB, Rabbani M, Sheng Y, Agrawal R, Glass-Klaiber J, Sultan C, Camarillo JM, Clements J, Baldwin MR, Diehl AG, Boyle AP, O'Brien PJ, Ragunathan K, Hu YC, Kelleher NL, Nandakumar J, Li JZ, Orwig KE, Redding S, Hammoud SS. Sperm chromatin structure and reproductive fitness are altered by substitution of a single amino acid in mouse protamine 1. Nat Struct Mol Biol 2023; 30:1077-1091. [PMID: 37460896 PMCID: PMC10833441 DOI: 10.1038/s41594-023-01033-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 06/12/2023] [Indexed: 08/11/2023]
Abstract
Conventional dogma presumes that protamine-mediated DNA compaction in sperm is achieved by electrostatic interactions between DNA and the arginine-rich core of protamines. Phylogenetic analysis reveals several non-arginine residues conserved within, but not across species. The significance of these residues and their post-translational modifications are poorly understood. Here, we investigated the role of K49, a rodent-specific lysine residue in protamine 1 (P1) that is acetylated early in spermiogenesis and retained in sperm. In sperm, alanine substitution (P1(K49A)) decreases sperm motility and male fertility-defects that are not rescued by arginine substitution (P1(K49R)). In zygotes, P1(K49A) leads to premature male pronuclear decompaction, altered DNA replication, and embryonic arrest. In vitro, P1(K49A) decreases protamine-DNA binding and alters DNA compaction and decompaction kinetics. Hence, a single amino acid substitution outside the P1 arginine core is sufficient to profoundly alter protein function and developmental outcomes, suggesting that protamine non-arginine residues are essential for reproductive fitness.
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Affiliation(s)
- Lindsay Moritz
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Samantha B Schon
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA
| | - Mashiat Rabbani
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Yi Sheng
- Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Ritvija Agrawal
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Juniper Glass-Klaiber
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Caleb Sultan
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Jeannie M Camarillo
- Departments of Chemistry, Molecular Biosciences, and the National Resource for Translational and Developmental Proteomics, Northwestern University, Evanston, IL, USA
| | - Jourdan Clements
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Michael R Baldwin
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Adam G Diehl
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Alan P Boyle
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Patrick J O'Brien
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI, USA
| | | | - Yueh-Chiang Hu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Neil L Kelleher
- Departments of Chemistry, Molecular Biosciences, and the National Resource for Translational and Developmental Proteomics, Northwestern University, Evanston, IL, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jun Z Li
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Kyle E Orwig
- Department of Obstetrics, Gynecology and Reproductive Sciences, Magee Womens Research Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sy Redding
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Saher Sue Hammoud
- Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, MI, USA.
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA.
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA.
- Department of Urology, University of Michigan, Ann Arbor, MI, USA.
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2
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Ivanovaitė ŠRN, Paksaitė J, Kopu Stas A, Karzaitė G, Rutkauskas D, Silanskas A, Sasnauskas G, Zaremba M, Jones SK, Tutkus M. smFRET Detection of Cis and Trans DNA Interactions by the BfiI Restriction Endonuclease. J Phys Chem B 2023. [PMID: 37452775 PMCID: PMC10388346 DOI: 10.1021/acs.jpcb.3c03269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023]
Abstract
Protein-DNA interactions are fundamental to many biological processes. Proteins must find their target site on a DNA molecule to perform their function, and mechanisms for target search differ across proteins. Especially challenging phenomena to monitor and understand are transient binding events that occur across two DNA target sites, whether occurring in cis or trans. Type IIS restriction endonucleases rely on such interactions. They play a crucial role in safeguarding bacteria against foreign DNA, including viral genetic material. BfiI, a type IIS restriction endonuclease, acts upon a specific asymmetric sequence, 5-ACTGGG-3, and precisely cuts both upper and lower DNA strands at fixed locations downstream of this sequence. Here, we present two single-molecule Förster resonance energy-transfer-based assays to study such interactions in a BfiI-DNA system. The first assay focuses on DNA looping, detecting both "Phi"- and "U"-shaped DNA looping events. The second assay only allows in trans BfiI-target DNA interactions, improving the specificity and reducing the limits on observation time. With total internal reflection fluorescence microscopy, we directly observe on- and off-target binding events and characterize BfiI binding events. Our results show that BfiI binds longer to target sites and that BfiI rarely changes conformations during binding. This newly developed assay could be employed for other DNA-interacting proteins that bind two targets and for the dsDNA substrate BfiI-PAINT, a useful strategy for DNA stretch assays and other super-resolution fluorescence microscopy studies.
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Affiliation(s)
- Ša Ru Nė Ivanovaitė
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Savanorių 231, Vilnius LT-02300, Lithuania
- Vilnius University, Life Sciences Center, Institute of Biotechnology, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Justė Paksaitė
- Vilnius University, Life Sciences Center, Institute of Biotechnology, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Aurimas Kopu Stas
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Savanorių 231, Vilnius LT-02300, Lithuania
- Vilnius University, Life Sciences Center, Institute of Biotechnology, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Giedrė Karzaitė
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Savanorių 231, Vilnius LT-02300, Lithuania
| | - Danielis Rutkauskas
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Savanorių 231, Vilnius LT-02300, Lithuania
| | - Arunas Silanskas
- Vilnius University, Life Sciences Center, Institute of Biotechnology, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Giedrius Sasnauskas
- Vilnius University, Life Sciences Center, Institute of Biotechnology, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Mindaugas Zaremba
- Vilnius University, Life Sciences Center, Institute of Biotechnology, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
| | - Stephen K Jones
- VU LSC-EMBL Partnership for Genome Editing Technologies, Life Sciences Center, Vilnius University, Vilnius LT-10257, Lithuania
| | - Marijonas Tutkus
- Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Savanorių 231, Vilnius LT-02300, Lithuania
- Vilnius University, Life Sciences Center, Institute of Biotechnology, Saulėtekio av. 7, Vilnius LT-10257, Lithuania
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3
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Montalbo RCK, Tu HL. Micropatterning of functional lipid bilayer assays for quantitative bioanalysis. BIOMICROFLUIDICS 2023; 17:031302. [PMID: 37179590 PMCID: PMC10171888 DOI: 10.1063/5.0145997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023]
Abstract
Interactions of the cell with its environment are mediated by the cell membrane and membrane-localized molecules. Supported lipid bilayers have enabled the recapitulation of the basic properties of cell membranes and have been broadly used to further our understanding of cellular behavior. Coupled with micropatterning techniques, lipid bilayer platforms have allowed for high throughput assays capable of performing quantitative analysis at a high spatiotemporal resolution. Here, an overview of the current methods of the lipid membrane patterning is presented. The fabrication and pattern characteristics are briefly described to present an idea of the quality and notable features of the methods, their utilizations for quantitative bioanalysis, as well as to highlight possible directions for the advanced micropatterning lipid membrane assays.
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4
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Soniat MM, Nguyen G, Kuo HC, Finkelstein IJ. The MRN complex and topoisomerase IIIa-RMI1/2 synchronize DNA resection motor proteins. J Biol Chem 2023; 299:102802. [PMID: 36529288 PMCID: PMC9971906 DOI: 10.1016/j.jbc.2022.102802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/08/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
DNA resection-the nucleolytic processing of broken DNA ends-is the first step of homologous recombination. Resection is catalyzed by the resectosome, a multienzyme complex that includes bloom syndrome helicase (BLM), DNA2 or exonuclease 1 nucleases, and additional DNA-binding proteins. Although the molecular players have been known for over a decade, how the individual proteins work together to regulate DNA resection remains unknown. Using single-molecule imaging, we characterized the roles of the MRE11-RAD50-NBS1 complex (MRN) and topoisomerase IIIa (TOP3A)-RMI1/2 during long-range DNA resection. BLM partners with TOP3A-RMI1/2 to form the BTRR (BLM-TOP3A-RMI1/2) complex (or BLM dissolvasome). We determined that TOP3A-RMI1/2 aids BLM in initiating DNA unwinding, and along with MRN, stimulates DNA2-mediated resection. Furthermore, we found that MRN promotes the association between BTRR and DNA and synchronizes BLM and DNA2 translocation to prevent BLM from pausing during resection. Together, this work provides direct observation of how MRN and DNA2 harness the BTRR complex to resect DNA efficiently and how TOP3A-RMI1/2 regulates the helicase activity of BLM to promote efficient DNA repair.
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Affiliation(s)
- Michael M Soniat
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA.
| | - Giaochau Nguyen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Hung-Che Kuo
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, USA.
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Crickard JB. Single Molecule Imaging of DNA-Protein Interactions Using DNA Curtains. Methods Mol Biol 2023; 2599:127-139. [PMID: 36427147 PMCID: PMC10082465 DOI: 10.1007/978-1-0716-2847-8_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Direct observation of enzymes that work to promote nucleic acid metabolism is a powerful approach to understanding their biochemical and biological properties. Over several years, fluorescent optical microscopy has developed as a powerful tool for watching biological pathways as they occur in real time. Here we describe DNA curtains as an optical microscopy tool that combines engineering, biochemistry, and single molecule imaging to make direct observations of enzymes as they work on DNA in real time. We will provide a detailed methodology of this approach including information about the setup of a basic TIRF microscope, assembly of flow chambers for imaging, and the protocol for making DNA curtains. Our goal is to help the reader better understand the technical approaches to DNA curtains and to better understand the biochemical and biological applications of this approach.
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Affiliation(s)
- J Brooks Crickard
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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6
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Schaub JM, Soniat MM, Finkelstein IJ. Polymerase theta-helicase promotes end joining by stripping single-stranded DNA-binding proteins and bridging DNA ends. Nucleic Acids Res 2022; 50:3911-3921. [PMID: 35357490 PMCID: PMC9023281 DOI: 10.1093/nar/gkac119] [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: 06/03/2021] [Revised: 01/20/2022] [Accepted: 03/29/2022] [Indexed: 01/20/2023] Open
Abstract
Homologous recombination-deficient cancers rely on DNA polymerase Theta (Polθ)-Mediated End Joining (TMEJ), an alternative double-strand break repair pathway. Polθ is the only vertebrate polymerase that encodes an N-terminal superfamily 2 (SF2) helicase domain, but the role of this helicase domain in TMEJ remains unclear. Using single-molecule imaging, we demonstrate that Polθ-helicase (Polθ-h) is a highly processive single-stranded DNA (ssDNA) motor protein that can efficiently strip Replication Protein A (RPA) from ssDNA. Polθ-h also has a limited capacity for disassembling RAD51 filaments but is not processive on double-stranded DNA. Polθ-h can bridge two non-complementary DNA strands in trans. PARylation of Polθ-h by PARP-1 resolves these DNA bridges. We conclude that Polθ-h removes RPA and RAD51 filaments and mediates bridging of DNA overhangs to aid in polymerization by the Polθ polymerase domain.
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Affiliation(s)
- Jeffrey M Schaub
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Michael M Soniat
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
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7
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Fairlamb MS, Whitaker AM, Bain FE, Spies M, Freudenthal BD. Construction of a Three-Color Prism-Based TIRF Microscope to Study the Interactions and Dynamics of Macromolecules. BIOLOGY 2021; 10:biology10070571. [PMID: 34201434 PMCID: PMC8301196 DOI: 10.3390/biology10070571] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/08/2021] [Accepted: 06/15/2021] [Indexed: 02/05/2023]
Abstract
Simple Summary Prism-based single-molecule total internal reflection fluorescence (prismTIRF) microscopes are excellent tools for studying macromolecular dynamics and interactions. Here, we provide an easy-to-follow guide for the design, assembly, and operation of a three-color prismTIRF microscope using commercially available components with the hope of assisting those who aim to implement TIRF imaging techniques in their laboratory. Abstract Single-molecule total internal reflection fluorescence (TIRF) microscopy allows for the real-time visualization of macromolecular dynamics and complex assembly. Prism-based TIRF microscopes (prismTIRF) are relatively simple to operate and can be easily modulated to fit the needs of a wide variety of experimental applications. While building a prismTIRF microscope without expert assistance can pose a significant challenge, the components needed to build a prismTIRF microscope are relatively affordable and, with some guidance, the assembly can be completed by a determined novice. Here, we provide an easy-to-follow guide for the design, assembly, and operation of a three-color prismTIRF microscope which can be utilized for the study of macromolecular complexes, including the multi-component protein–DNA complexes responsible for DNA repair, replication, and transcription. Our hope is that this article can assist laboratories that aspire to implement single-molecule TIRF techniques, and consequently expand the application of this technology.
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Affiliation(s)
- Max S. Fairlamb
- Department of Biochemistry and Molecular Biology and Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (M.S.F.); (A.M.W.)
| | - Amy M. Whitaker
- Department of Biochemistry and Molecular Biology and Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (M.S.F.); (A.M.W.)
| | - Fletcher E. Bain
- Department of Biochemistry and Molecular Biology, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA; (F.E.B.); (M.S.)
| | - Maria Spies
- Department of Biochemistry and Molecular Biology, University of Iowa Carver College of Medicine, 51 Newton Road, Iowa City, IA 52242, USA; (F.E.B.); (M.S.)
| | - Bret D. Freudenthal
- Department of Biochemistry and Molecular Biology and Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (M.S.F.); (A.M.W.)
- Correspondence:
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8
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Molecular basis of the dual role of the Mlh1-Mlh3 endonuclease in MMR and in meiotic crossover formation. Proc Natl Acad Sci U S A 2021; 118:2022704118. [PMID: 34088835 DOI: 10.1073/pnas.2022704118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In budding yeast, the MutL homolog heterodimer Mlh1-Mlh3 (MutLγ) plays a central role in the formation of meiotic crossovers. It is also involved in the repair of a subset of mismatches besides the main mismatch repair (MMR) endonuclease Mlh1-Pms1 (MutLα). The heterodimer interface and endonuclease sites of MutLγ and MutLα are located in their C-terminal domain (CTD). The molecular basis of MutLγ's dual roles in MMR and meiosis is not known. To better understand the specificity of MutLγ, we characterized the crystal structure of Saccharomyces cerevisiae MutLγ(CTD). Although MutLγ(CTD) presents overall similarities with MutLα(CTD), it harbors some rearrangement of the surface surrounding the active site, which indicates altered substrate preference. The last amino acids of Mlh1 participate in the Mlh3 endonuclease site as previously reported for Pms1. We characterized mlh1 alleles and showed a critical role of this Mlh1 extreme C terminus both in MMR and in meiotic recombination. We showed that the MutLγ(CTD) preferentially binds Holliday junctions, contrary to MutLα(CTD). We characterized Mlh3 positions on the N-terminal domain (NTD) and CTD that could contribute to the positioning of the NTD close to the CTD in the context of the full-length MutLγ. Finally, crystal packing revealed an assembly of MutLγ(CTD) molecules in filament structures. Mutation at the corresponding interfaces reduced crossover formation, suggesting that these superstructures may contribute to the oligomer formation proposed for MutLγ. This study defines clear divergent features between the MutL homologs and identifies, at the molecular level, their specialization toward MMR or meiotic recombination functions.
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9
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Loeff L, Kerssemakers JWJ, Joo C, Dekker C. AutoStepfinder: A fast and automated step detection method for single-molecule analysis. PATTERNS 2021; 2:100256. [PMID: 34036291 PMCID: PMC8134948 DOI: 10.1016/j.patter.2021.100256] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/12/2020] [Accepted: 04/08/2021] [Indexed: 01/05/2023]
Abstract
Single-molecule techniques allow the visualization of the molecular dynamics of nucleic acids and proteins with high spatiotemporal resolution. Valuable kinetic information of biomolecules can be obtained when the discrete states within single-molecule time trajectories are determined. Here, we present a fast, automated, and bias-free step detection method, AutoStepfinder, that determines steps in large datasets without requiring prior knowledge on the noise contributions and location of steps. The analysis is based on a series of partition events that minimize the difference between the data and the fit. A dual-pass strategy determines the optimal fit and allows AutoStepfinder to detect steps of a wide variety of sizes. We demonstrate step detection for a broad variety of experimental traces. The user-friendly interface and the automated detection of AutoStepfinder provides a robust analysis procedure that enables anyone without programming knowledge to generate step fits and informative plots in less than an hour. Fast, automated, and bias-free detection of steps within single-molecule trajectories Robust step detection without any prior knowledge on the data A dual-pass strategy for the detection of steps over a wide variety of scales A user-friendly interface for a simplified step fitting procedure
Single-molecule techniques have made it possible to track individual protein complexes in real time with a nanometer spatial resolution and a millisecond timescale. Accurate determination of the dynamic states within single-molecule time traces provides valuable kinetic information that underlie the function of biological macromolecules. Here, we present a new automated step detection method called AutoStepfinder, a versatile, robust, and easy-to-use algorithm that allows researchers to determine the kinetic states within single-molecule time trajectories without any bias.
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Affiliation(s)
- Luuk Loeff
- Kavli Institute of Nanoscience and Department of Bionanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Jacob W J Kerssemakers
- Kavli Institute of Nanoscience and Department of Bionanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Chirlmin Joo
- Kavli Institute of Nanoscience and Department of Bionanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Cees Dekker
- Kavli Institute of Nanoscience and Department of Bionanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
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10
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Calcines-Cruz C, Finkelstein IJ, Hernandez-Garcia A. CRISPR-Guided Programmable Self-Assembly of Artificial Virus-Like Nucleocapsids. NANO LETTERS 2021; 21:2752-2757. [PMID: 33729813 PMCID: PMC9724498 DOI: 10.1021/acs.nanolett.0c04640] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Designer virus-inspired proteins drive the manufacturing of more effective, safer gene-delivery systems and simpler models to study viral assembly. However, self-assembly of engineered viromimetic proteins on specific nucleic acid templates, a distinctive viral property, has proved difficult. Inspired by viral packaging signals, we harness the programmability of CRISPR-Cas12a to direct the nucleation and growth of a self-assembling synthetic polypeptide into virus-like particles (VLP) on specific DNA molecules. Positioning up to ten nuclease-dead Cas12a (dCas12a) proteins along a 48.5 kbp DNA template triggers particle growth and full DNA encapsidation at limiting polypeptide concentrations. Particle growth rate is further increased when dCas12a is dimerized with a polymerization silk-like domain. Such improved self-assembly efficiency allows for discrimination between cognate versus noncognate DNA templates by the synthetic polypeptide. CRISPR-guided VLPs will help to develop programmable bioinspired nanomaterials with applications in biotechnology as well as viromimetic scaffolds to improve our understanding of viral self-assembly.
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Affiliation(s)
- Carlos Calcines-Cruz
- Department of Chemistry of Biomacromolecules, Institute of Chemistry, National Autonomous University of Mexico, Mexico City C.P. 04510, Mexico
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11
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Kopu̅stas A, Ivanovaitė Š, Rakickas T, Pocevičiu̅tė E, Paksaitė J, Karvelis T, Zaremba M, Manakova E, Tutkus M. Oriented Soft DNA Curtains for Single-Molecule Imaging. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:3428-3437. [PMID: 33689355 PMCID: PMC8280724 DOI: 10.1021/acs.langmuir.1c00066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Over the past 20 years, single-molecule methods have become extremely important for biophysical studies. These methods, in combination with new nanotechnological platforms, can significantly facilitate experimental design and enable faster data acquisition. A nanotechnological platform, which utilizes a flow-stretch of immobilized DNA molecules, called DNA Curtains, is one of the best examples of such combinations. Here, we employed new strategies to fabricate a flow-stretch assay of stably immobilized and oriented DNA molecules using a protein template-directed assembly. In our assay, a protein template patterned on a glass coverslip served for directional assembly of biotinylated DNA molecules. In these arrays, DNA molecules were oriented to one another and maintained extended by either single- or both-end immobilization to the protein templates. For oriented both-end DNA immobilization, we employed heterologous DNA labeling and protein template coverage with the antidigoxigenin antibody. In contrast to single-end immobilization, both-end immobilization does not require constant buffer flow for keeping DNAs in an extended configuration, allowing us to study protein-DNA interactions at more controllable reaction conditions. Additionally, we increased the immobilization stability of the biotinylated DNA molecules using protein templates fabricated from traptavidin. Finally, we demonstrated that double-tethered Soft DNA Curtains can be used in nucleic acid-interacting protein (e.g., CRISPR-Cas9) binding assay that monitors the binding location and position of individual fluorescently labeled proteins on DNA.
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Affiliation(s)
- Aurimas Kopu̅stas
- Departments
of Molecular Compound Physics, Nanoengineering, and Functional Materials and Electronics, Center for Physical Sciences and Technology, Savanoriu 231, Vilnius LT-02300, Lithuania
- Life
Sciences Center, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Šaru̅nė Ivanovaitė
- Departments
of Molecular Compound Physics, Nanoengineering, and Functional Materials and Electronics, Center for Physical Sciences and Technology, Savanoriu 231, Vilnius LT-02300, Lithuania
| | - Tomas Rakickas
- Departments
of Molecular Compound Physics, Nanoengineering, and Functional Materials and Electronics, Center for Physical Sciences and Technology, Savanoriu 231, Vilnius LT-02300, Lithuania
| | - Ernesta Pocevičiu̅tė
- Departments
of Molecular Compound Physics, Nanoengineering, and Functional Materials and Electronics, Center for Physical Sciences and Technology, Savanoriu 231, Vilnius LT-02300, Lithuania
- Life
Sciences Center, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Justė Paksaitė
- Life
Sciences Center, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Tautvydas Karvelis
- Life
Sciences Center, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Mindaugas Zaremba
- Life
Sciences Center, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Elena Manakova
- Life
Sciences Center, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
| | - Marijonas Tutkus
- Departments
of Molecular Compound Physics, Nanoengineering, and Functional Materials and Electronics, Center for Physical Sciences and Technology, Savanoriu 231, Vilnius LT-02300, Lithuania
- Life
Sciences Center, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257 Vilnius, Lithuania
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12
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Keenen MM, Brown D, Brennan LD, Renger R, Khoo H, Carlson CR, Huang B, Grill SW, Narlikar GJ, Redding S. HP1 proteins compact DNA into mechanically and positionally stable phase separated domains. eLife 2021; 10:e64563. [PMID: 33661100 PMCID: PMC7932698 DOI: 10.7554/elife.64563] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 02/22/2021] [Indexed: 12/11/2022] Open
Abstract
In mammals, HP1-mediated heterochromatin forms positionally and mechanically stable genomic domains even though the component HP1 paralogs, HP1α, HP1β, and HP1γ, display rapid on-off dynamics. Here, we investigate whether phase-separation by HP1 proteins can explain these biological observations. Using bulk and single-molecule methods, we show that, within phase-separated HP1α-DNA condensates, HP1α acts as a dynamic liquid, while compacted DNA molecules are constrained in local territories. These condensates are resistant to large forces yet can be readily dissolved by HP1β. Finally, we find that differences in each HP1 paralog's DNA compaction and phase-separation properties arise from their respective disordered regions. Our findings suggest a generalizable model for genome organization in which a pool of weakly bound proteins collectively capitalize on the polymer properties of DNA to produce self-organizing domains that are simultaneously resistant to large forces at the mesoscale and susceptible to competition at the molecular scale.
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Affiliation(s)
- Madeline M Keenen
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Tetrad Graduate Program, University of California, San FranciscoSan FranciscoUnited States
| | - David Brown
- Department of Pharmaceutical Chemistry, University of California, San FranciscoSan FranciscoUnited States
| | - Lucy D Brennan
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Roman Renger
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- German Center for Neurodegenerative Diseases (DZNE)BonnGermany
| | - Harrison Khoo
- Department of Mechanical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Christopher R Carlson
- Tetrad Graduate Program, University of California, San FranciscoSan FranciscoUnited States
- Department of Physiology, University of California, San FranciscoSan FranciscoUnited States
| | - Bo Huang
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Department of Pharmaceutical Chemistry, University of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Stephan W Grill
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Cluster of Excellence Physics of Life, Technische Universität DresdenDresdenGermany
| | - Geeta J Narlikar
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
| | - Sy Redding
- Department of Biochemistry and Biophysics, University of California, San FranciscoSan FranciscoUnited States
- Marine Biological LaboratoryWoods HoleUnited States
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13
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Takahashi S, Oshige M, Katsura S. DNA Manipulation and Single-Molecule Imaging. Molecules 2021; 26:1050. [PMID: 33671359 PMCID: PMC7922115 DOI: 10.3390/molecules26041050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 11/22/2022] Open
Abstract
DNA replication, repair, and recombination in the cell play a significant role in the regulation of the inheritance, maintenance, and transfer of genetic information. To elucidate the biomolecular mechanism in the cell, some molecular models of DNA replication, repair, and recombination have been proposed. These biological studies have been conducted using bulk assays, such as gel electrophoresis. Because in bulk assays, several millions of biomolecules are subjected to analysis, the results of the biological analysis only reveal the average behavior of a large number of biomolecules. Therefore, revealing the elementary biological processes of a protein acting on DNA (e.g., the binding of protein to DNA, DNA synthesis, the pause of DNA synthesis, and the release of protein from DNA) is difficult. Single-molecule imaging allows the analysis of the dynamic behaviors of individual biomolecules that are hidden during bulk experiments. Thus, the methods for single-molecule imaging have provided new insights into almost all of the aspects of the elementary processes of DNA replication, repair, and recombination. However, in an aqueous solution, DNA molecules are in a randomly coiled state. Thus, the manipulation of the physical form of the single DNA molecules is important. In this review, we provide an overview of the unique studies on DNA manipulation and single-molecule imaging to analyze the dynamic interaction between DNA and protein.
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Affiliation(s)
- Shunsuke Takahashi
- Division of Life Science and Engineering, School of Science and Engineering, Tokyo Denki University, Hatoyama-cho, Hiki-gun, Saitama 350-0394, Japan;
| | - Masahiko Oshige
- Department of Environmental Engineering Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan;
- Gunma University Center for Food Science and Wellness (GUCFW), Maebashi, Gunma 371-8510, Japan
| | - Shinji Katsura
- Department of Environmental Engineering Science, Graduate School of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan;
- Gunma University Center for Food Science and Wellness (GUCFW), Maebashi, Gunma 371-8510, Japan
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14
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Zhang H, Schaub JM, Finkelstein IJ. RADX condenses single-stranded DNA to antagonize RAD51 loading. Nucleic Acids Res 2020; 48:7834-7843. [PMID: 32621611 PMCID: PMC7430644 DOI: 10.1093/nar/gkaa559] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 12/31/2022] Open
Abstract
RADX is a mammalian single-stranded DNA-binding protein that stabilizes telomeres and stalled replication forks. Cellular biology studies have shown that the balance between RADX and Replication Protein A (RPA) is critical for DNA replication integrity. RADX is also a negative regulator of RAD51-mediated homologous recombination at stalled forks. However, the mechanism of RADX acting on DNA and its interactions with RPA and RAD51 are enigmatic. Using single-molecule imaging of the key proteins in vitro, we reveal that RADX condenses ssDNA filaments, even when the ssDNA is coated with RPA at physiological protein ratios. RADX compacts RPA-coated ssDNA filaments via higher-order assemblies that can capture ssDNA in trans. Furthermore, RADX blocks RPA displacement by RAD51 and prevents RAD51 loading on ssDNA. Our results indicate that RADX is an ssDNA condensation protein that inhibits RAD51 filament formation and may antagonize other ssDNA-binding proteins on RPA-coated ssDNA.
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Affiliation(s)
- Hongshan Zhang
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA.,Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
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15
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Epigenetic cell fate in Candida albicans is controlled by transcription factor condensates acting at super-enhancer-like elements. Nat Microbiol 2020; 5:1374-1389. [PMID: 32719507 PMCID: PMC7581547 DOI: 10.1038/s41564-020-0760-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/25/2020] [Indexed: 12/21/2022]
Abstract
Cell identity in eukaryotes is controlled by transcriptional regulatory networks (TRNs) that define cell type-specific gene expression. In the opportunistic fungal pathogen Candida albicans, TRNs regulate epigenetic switching between two alternative cell states, ‘white’ and ‘opaque’, that exhibit distinct host interactions. Here, we reveal that the transcription factors (TFs) regulating cell identity contain prion-like domains (PrLDs) that enable liquid-liquid demixing and the formation of phase-separated condensates. Multiple white-opaque TFs can co-assemble into complex condensates as observed on single DNA molecules. Moreover, heterotypic interactions between PrLDs supports the assembly of multifactorial condensates at a synthetic locus within live eukaryotic cells. Mutation of the Wor1 PrLD revealed that substitution of acidic residues abolished its ability to phase separate and to co-recruit other TFs in live cells, as well as its function in C. albicans cell fate determination. Together, these studies reveal that PrLDs support the assembly of TF complexes that control fungal cell identity and highlight parallels with the ‘super-enhancers’ that regulate mammalian cell fate.
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16
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Inukai R, Takao H, Shimokawa F, Terao K. Capture and elongation of single chromosomal DNA molecules using optically driven microchopsticks. BIOMICROFLUIDICS 2020; 14:044114. [PMID: 32831987 PMCID: PMC7428348 DOI: 10.1063/5.0017727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/05/2020] [Indexed: 05/11/2023]
Abstract
DNA analysis based on the observation of single DNA molecules has been a key technology in molecular biology. Several techniques for manipulating single DNA molecules have been proposed for this purpose; however, these techniques have limits on the manipulatable DNA. To overcome this, we demonstrate a method of DNA manipulation using microstructures captured by optical tweezers that allow the manipulation of a chromosomal DNA molecule. For proper DNA handling, we developed microstructures analogous to chopsticks to capture and elongate single DNA molecules under an optical microscope. Two microstructures (i.e., microchopsticks) were captured by two focused laser beams to pinch a single yeast chromosomal DNA molecule between them and thereby manipulate it. The experiments demonstrated successful DNA manipulation and revealed that the size and geometry of the microchopsticks are important factors for effective DNA handling. This technique allows a high degree of freedom in handling single DNA molecules, potentially leading to applications in the study of chromosomal DNA.
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Affiliation(s)
- Ryo Inukai
- Department of Intelligent Mechanical Systems Engineering, Kagawa University, Takamatsu 761-0396, Japan
| | | | | | - Kyohei Terao
- Author to whom correspondence should be addressed:. Tel.: +81 (87) 864-2346
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17
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Limiting the DNA Double-Strand Break Resectosome for Genome Protection. Trends Biochem Sci 2020; 45:779-793. [PMID: 32513599 DOI: 10.1016/j.tibs.2020.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/20/2020] [Accepted: 05/05/2020] [Indexed: 12/15/2022]
Abstract
DNA double-strand break (DSB) resection, once thought to be a simple enzymatic process, is emerging as a highly complex series of coordinated activities required to maintain genome integrity. Progress in cell biology, biochemistry, and genetics has deciphered the precise resecting activities, the regulatory components, and their ability to properly channel the resected DNA to the appropriate DNA repair pathway. Herein, we review the mechanisms of regulation of DNA resection, with an emphasis on negative regulators that prevent single-strand (ss)DNA accumulation to maintain genome stability. Interest in targeting DNA resection inhibitors is emerging because their inactivation leads to poly(ADP-ribose) polymerase inhibitor (PARPi) resistance. We also present detailed regulation of DNA resection machineries, their analysis by functional assays, and their impact on disease and PARPi resistance.
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18
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Kang Y, Cheon NY, Cha J, Kim A, Kim HI, Lee L, Kim KO, Jo K, Lee JY. High-throughput single-molecule imaging system using nanofabricated trenches and fluorescent DNA-binding proteins. Biotechnol Bioeng 2020; 117:1640-1648. [PMID: 32162675 DOI: 10.1002/bit.27331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/02/2020] [Accepted: 03/11/2020] [Indexed: 12/18/2022]
Abstract
DNA curtain is a high-throughput system, integrating a lipid bilayer, fluorescence imaging, and microfluidics to probe protein-DNA interactions in real-time and has provided in-depth understanding of DNA metabolism. Especially, the microfluidic platform of a DNA curtain is highly suitable for a biochip. In the DNA curtain, DNA molecules are aligned along chromium nanobarriers, which are fabricated on a slide surface, and visualized using an intercalating dye, YOYO-1. Although the chromium barriers confer precise geometric alignment of DNA, reuse of the slides is limited by wear of the barriers during cleaning. YOYO-1 is rapidly photobleached and causes photocleavage of DNA under continuous laser illumination, restricting DNA observation to a brief time window. To address these challenges, we developed a new nanopatterned slide, upon which carved nanotrenches serve as diffusion barriers. The nanotrenches were robust under harsh cleaning conditions, facilitating the maintenance of surface cleanliness that is essential to slide reuse. We also stained DNA with a fluorescent protein with a DNA-binding motif, fluorescent protein-DNA binding peptide (FP-DBP). FP-DBP was slowly photobleached and did not cause DNA photocleavage. This new DNA curtain system enables a more stable and repeatable investigation of real-time protein-DNA interactions and will serve as a good platform for lab-on-a-chip.
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Affiliation(s)
- Yujin Kang
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Na Young Cheon
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jongjin Cha
- Department of Physics and Astronomy, Seoul National University, Seoul, Republic of Korea
| | - Ayoung Kim
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Hyung-Il Kim
- UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Luda Lee
- UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Kang O Kim
- UNIST Central Research Facilities (UCRF), Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Kyubong Jo
- Department of Chemistry and Integrated Biotechnology, Sogang University, Seoul, Republic of Korea
| | - Ja Yil Lee
- School of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.,Center for Genomic Integrity, Institute for Basic Science, Ulsan, Republic of Korea
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19
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Deshpande RA, Myler LR, Soniat MM, Makharashvili N, Lee L, Lees-Miller SP, Finkelstein IJ, Paull TT. DNA-dependent protein kinase promotes DNA end processing by MRN and CtIP. SCIENCE ADVANCES 2020; 6:eaay0922. [PMID: 31934630 PMCID: PMC6949041 DOI: 10.1126/sciadv.aay0922] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Abstract
The repair of DNA double-strand breaks occurs through nonhomologous end joining or homologous recombination in vertebrate cells-a choice that is thought to be decided by a competition between DNA-dependent protein kinase (DNA-PK) and the Mre11/Rad50/Nbs1 (MRN) complex but is not well understood. Using ensemble biochemistry and single-molecule approaches, here, we show that the MRN complex is dependent on DNA-PK and phosphorylated CtIP to perform efficient processing and resection of DNA ends in physiological conditions, thus eliminating the competition model. Endonucleolytic removal of DNA-PK-bound DNA ends is also observed at double-strand break sites in human cells. The involvement of DNA-PK in MRN-mediated end processing promotes an efficient and sequential transition from nonhomologous end joining to homologous recombination by facilitating DNA-PK removal.
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Affiliation(s)
- Rajashree A. Deshpande
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Logan R. Myler
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY 10065, USA
| | - Michael M. Soniat
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Nodar Makharashvili
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Linda Lee
- Department of Biochemistry and Molecular Biology, University of Calgary, Alberta T2N 1N4, Canada
| | - Susan P. Lees-Miller
- Department of Biochemistry and Molecular Biology, University of Calgary, Alberta T2N 1N4, Canada
| | - Ilya J. Finkelstein
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
- Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Tanya T. Paull
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
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20
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Kim Y, Shi Z, Zhang H, Finkelstein IJ, Yu H. Human cohesin compacts DNA by loop extrusion. Science 2019; 366:1345-1349. [PMID: 31780627 PMCID: PMC7387118 DOI: 10.1126/science.aaz4475] [Citation(s) in RCA: 388] [Impact Index Per Article: 77.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/11/2019] [Accepted: 11/16/2019] [Indexed: 12/23/2022]
Abstract
Cohesin is a chromosome-bound, multisubunit adenosine triphosphatase complex. After loading onto chromosomes, it generates loops to regulate chromosome functions. It has been suggested that cohesin organizes the genome through loop extrusion, but direct evidence is lacking. Here, we used single-molecule imaging to show that the recombinant human cohesin-NIPBL complex compacts both naked and nucleosome-bound DNA by extruding DNA loops. DNA compaction by cohesin requires adenosine triphosphate (ATP) hydrolysis and is force sensitive. This compaction is processive over tens of kilobases at an average rate of 0.5 kilobases per second. Compaction of double-tethered DNA suggests that a cohesin dimer extrudes DNA loops bidirectionally. Our results establish cohesin-NIPBL as an ATP-driven molecular machine capable of loop extrusion.
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Affiliation(s)
- Yoori Kim
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zhubing Shi
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hongshan Zhang
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
| | - Hongtao Yu
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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21
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Caron MC, Sharma AK, O'Sullivan J, Myler LR, Ferreira MT, Rodrigue A, Coulombe Y, Ethier C, Gagné JP, Langelier MF, Pascal JM, Finkelstein IJ, Hendzel MJ, Poirier GG, Masson JY. Poly(ADP-ribose) polymerase-1 antagonizes DNA resection at double-strand breaks. Nat Commun 2019; 10:2954. [PMID: 31273204 PMCID: PMC6609622 DOI: 10.1038/s41467-019-10741-9] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Accepted: 05/29/2019] [Indexed: 12/20/2022] Open
Abstract
PARP-1 is rapidly recruited and activated by DNA double-strand breaks (DSBs). Upon activation, PARP-1 synthesizes a structurally complex polymer composed of ADP-ribose units that facilitates local chromatin relaxation and the recruitment of DNA repair factors. Here, we identify a function for PARP-1 in DNA DSB resection. Remarkably, inhibition of PARP-1 leads to hyperresected DNA DSBs. We show that loss of PARP-1 and hyperresection are associated with loss of Ku, 53BP1 and RIF1 resection inhibitors from the break site. DNA curtains analysis show that EXO1-mediated resection is blocked by PARP-1. Furthermore, PARP-1 abrogation leads to increased DNA resection tracks and an increase of homologous recombination in cellulo. Our results, therefore, place PARP-1 activation as a critical early event for DNA DSB repair activation and regulation of resection. Hence, our work has direct implications for the clinical use and effectiveness of PARP inhibition, which is prescribed for the treatment of various malignancies. Poly(ADP-ribose) polymerase-1 (PARP-1) facilitates local chromatin relaxation and the recruitment of DNA repair factors at double strand breaks site (DSBs). Here the authors reveal that PARP-1 acts as a critical regulator of DNA end resection of DSBs.
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Affiliation(s)
- Marie-Christine Caron
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, 9 McMahon, Québec City, QC, G1R 3S3, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada
| | - Ajit K Sharma
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue, Edmonton, AL, T6G 1Z2, Canada
| | - Julia O'Sullivan
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, 9 McMahon, Québec City, QC, G1R 3S3, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada
| | - Logan R Myler
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Maria Tedim Ferreira
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada.,CHU de Québec Research Center, CHUL Pavilion, Oncology Division, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada
| | - Amélie Rodrigue
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, 9 McMahon, Québec City, QC, G1R 3S3, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada
| | - Yan Coulombe
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, 9 McMahon, Québec City, QC, G1R 3S3, Canada.,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada
| | - Chantal Ethier
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada.,CHU de Québec Research Center, CHUL Pavilion, Oncology Division, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada
| | - Jean-Philippe Gagné
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada.,CHU de Québec Research Center, CHUL Pavilion, Oncology Division, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada
| | - Marie-France Langelier
- Biochemistry and Molecular Medicine, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Pavillon Roger-Gaudry, Montréal, QC, H3T 1J4, Canada
| | - John M Pascal
- Biochemistry and Molecular Medicine, Université de Montréal, 2900 Boulevard Edouard-Montpetit, Pavillon Roger-Gaudry, Montréal, QC, H3T 1J4, Canada
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Michael J Hendzel
- Department of Oncology, Faculty of Medicine and Dentistry, University of Alberta, 11560 University Avenue, Edmonton, AL, T6G 1Z2, Canada.
| | - Guy G Poirier
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada. .,CHU de Québec Research Center, CHUL Pavilion, Oncology Division, 2705 Boulevard Laurier, Québec City, QC, G1V 4G2, Canada.
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, 9 McMahon, Québec City, QC, G1R 3S3, Canada. .,Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Québec City, QC, G1V 0A6, Canada.
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22
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Soniat MM, Myler LR, Kuo HC, Paull TT, Finkelstein IJ. RPA Phosphorylation Inhibits DNA Resection. Mol Cell 2019; 75:145-153.e5. [PMID: 31153714 DOI: 10.1016/j.molcel.2019.05.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 03/26/2019] [Accepted: 05/01/2019] [Indexed: 01/20/2023]
Abstract
Genetic recombination in all kingdoms of life initiates when helicases and nucleases process (resect) the free DNA ends to expose single-stranded DNA (ssDNA) overhangs. Resection regulation in bacteria is programmed by a DNA sequence, but a general mechanism limiting resection in eukaryotes has remained elusive. Using single-molecule imaging of reconstituted human DNA repair factors, we identify phosphorylated RPA (pRPA) as a negative resection regulator. Bloom's syndrome (BLM) helicase together with exonuclease 1 (EXO1) and DNA2 nucleases catalyze kilobase-length DNA resection on nucleosome-coated DNA. The resulting ssDNA is rapidly bound by RPA, which further stimulates DNA resection. RPA is phosphorylated during resection as part of the DNA damage response (DDR). Remarkably, pRPA inhibits DNA resection in cellular assays and in vitro via inhibition of BLM helicase. pRPA suppresses BLM initiation at DNA ends and promotes the intrinsic helicase strand-switching activity. These findings establish that pRPA provides a feedback loop between DNA resection and the DDR.
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Affiliation(s)
- Michael M Soniat
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Logan R Myler
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Hung-Che Kuo
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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23
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Tauran Y, Kumemura M, Tarhan MC, Perret G, Perret F, Jalabert L, Collard D, Fujita H, Coleman AW. Direct measurement of the mechanical properties of a chromatin analog and the epigenetic effects of para-sulphonato-calix[4]arene. Sci Rep 2019; 9:5816. [PMID: 30967623 PMCID: PMC6456576 DOI: 10.1038/s41598-019-42267-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 03/25/2019] [Indexed: 02/06/2023] Open
Abstract
By means of Silicon Nano Tweezers (SNTs) the effects on the mechanical properties of λ-phage DNA during interaction with calf thymus nucleosome to form an artificial chromatin analog were measured. At a concentration of 100 nM, a nucleosome solution induced a strong stiffening effect on DNA (1.1 N m-1). This can be compared to the effects of the histone proteins, H1, H2A, H3 where no changes in the mechanical properties of DNA were observed and the complex of the H3/H4 proteins where a smaller increase in the stiffness is observed (0.2 N m-1). Para-sulphonato-calix[4]arene, SC4, known for epigenetic activity by interacting specifically with the lysine groups of histone proteins, was studied for its effect on an artificial chromatin. Using a microfluidic SNT device, SC4 was titrated against the artificial chromatin, at a concentration of 1 mM in SC4 a considerable increase in stiffness, 15 N m-1, was observed. Simultaneously optical microscopy showed a physical change in the DNA structure between the tips of the SNT device. Electronic and Atomic Force microscopy confirmed this structural re-arrangement. Negative control experiments confirmed that these mechanical and physical effects were induced neither by the acidity of SC4 nor through nonspecific interactions of SC4 on DNA.
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Affiliation(s)
- Yannick Tauran
- LMI CNRS UMR 5615, Université Lyon 1, Villeurbanne, 69622, France.
- LIMMS/CNRS-IIS UMI 2820, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan.
| | - Momoko Kumemura
- LIMMS/CNRS-IIS UMI 2820, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
- CIRMM, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka, 808-0196, Japan
| | - Mehmet C Tarhan
- Univ. Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520-IEMN, Lille, F59000, France
- CNRS/IIS/COL/Lille 1 SMMiL-E project, 59046, Lille Cedex, France
| | - Grégoire Perret
- LIMMS/CNRS-IIS UMI 2820, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
- CNRS/IIS/COL/Lille 1 SMMiL-E project, 59046, Lille Cedex, France
| | - Florent Perret
- ICBMS, CNRS UMR 5246, Université Lyon 1, Villeurbanne, 69622, France
| | - Laurent Jalabert
- LIMMS/CNRS-IIS UMI 2820, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
- CIRMM, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
| | - Dominique Collard
- LIMMS/CNRS-IIS UMI 2820, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
- CNRS/IIS/COL/Lille 1 SMMiL-E project, 59046, Lille Cedex, France
| | - Hiroyuki Fujita
- LIMMS/CNRS-IIS UMI 2820, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
- CIRMM, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
| | - Anthony W Coleman
- CIRMM, Institute of Industrial Science, The University of Tokyo, Tokyo, 153-8505, Japan
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Kim Y, Furman CM, Manhart CM, Alani E, Finkelstein I. Intrinsically disordered regions regulate both catalytic and non-catalytic activities of the MutLα mismatch repair complex. Nucleic Acids Res 2019; 47:1823-1835. [PMID: 30541127 PMCID: PMC6393296 DOI: 10.1093/nar/gky1244] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/27/2018] [Accepted: 12/05/2018] [Indexed: 12/12/2022] Open
Abstract
Intrinsically disordered regions (IDRs) are present in at least 30% of the eukaryotic proteome and are enriched in chromatin-associated proteins. Using a combination of genetics, biochemistry and single-molecule biophysics, we characterize how IDRs regulate the functions of the yeast MutLα (Mlh1-Pms1) mismatch repair (MMR) complex. Shortening or scrambling the IDRs in both subunits ablates MMR in vivo. Mlh1-Pms1 complexes with shorter IDRs that disrupt MMR retain wild-type DNA binding affinity but are impaired for diffusion on both naked and nucleosome-coated DNA. Moreover, the IDRs also regulate the adenosine triphosphate hydrolysis and nuclease activities that are encoded in the structured N- and C-terminal domains of the complex. This combination of phenotypes underlies the catastrophic MMR defect seen with the mutant MutLα in vivo. More broadly, this work highlights an unanticipated multi-functional role for IDRs in regulating both facilitated diffusion on chromatin and nucleolytic processing of a DNA substrate.
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Affiliation(s)
- Yoori Kim
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Christopher M Furman
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Carol M Manhart
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Eric Alani
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
- Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
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Abstract
DNA double-strand breaks (DSBs) are a potentially lethal DNA lesions that disrupt both the physical and genetic continuity of the DNA duplex. Homologous recombination (HR) is a universally conserved genome maintenance pathway that initiates via nucleolytic processing of the broken DNA ends (resection). Eukaryotic DNA resection is catalyzed by the resectosome-a multicomponent molecular machine consisting of the nucleases DNA2 or Exonuclease 1 (EXO1), Bloom's helicase (BLM), the MRE11-RAD50-NBS1 (MRN) complex, and additional regulatory factors. Here, we describe methods for purification and single-molecule imaging and analysis of EXO1, DNA2, and BLM. We also describe how to adapt resection assays to the high-throughput single-molecule DNA curtain assay. By organizing hundreds of individual molecules on the surface of a microfluidic flowcell, DNA curtains visualize protein complexes with the required spatial and temporal resolution to resolve the molecular choreography during critical DNA-processing reactions.
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26
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Abstract
Fluorescent labeling of proteins is a critical requirement for single-molecule imaging studies. Many protein labeling strategies require harsh conditions or large epitopes that can inactivate the target protein, either by decreasing the protein's enzymatic activity or by blocking protein-protein interactions. Here, we provide a detailed protocol to efficiently label CRISPR-Cas complexes with a small fluorescent peptide via sortase-mediated transpeptidation. The sortase tag consists of just a few amino acids that are specifically recognized at either the N- or the C-terminus, making this strategy advantageous when the protein is part of a larger complex. Sortase is active at high ionic strength, 4°C, and with a broad range of organic fluorophores. We discuss the design, optimization, and single-molecule fluorescent imaging of CRISPR-Cas complexes on DNA curtains. Sortase-mediated transpeptidation is a versatile addition to the protein labeling toolkit.
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Schaub JM, Zhang H, Soniat MM, Finkelstein IJ. Assessing Protein Dynamics on Low-Complexity Single-Stranded DNA Curtains. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14882-14890. [PMID: 30044093 PMCID: PMC6679933 DOI: 10.1021/acs.langmuir.8b01812] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Single-stranded DNA (ssDNA) is a critical intermediate in all DNA transactions. Because ssDNA is more flexible than double-stranded (ds) DNA, interactions with ssDNA-binding proteins (SSBs) may significantly compact or elongate the ssDNA molecule. Here, we develop and characterize low-complexity ssDNA curtains, a high-throughput single-molecule assay to simultaneously monitor protein binding and correlated ssDNA length changes on supported lipid bilayers. Low-complexity ssDNA is generated via rolling circle replication of short synthetic oligonucleotides, permitting control over the sequence composition and secondary structure-forming propensity. One end of the ssDNA is functionalized with a biotin, while the second is fluorescently labeled to track the overall DNA length. Arrays of ssDNA molecules are organized at microfabricated barriers for high-throughput single-molecule imaging. Using this assay, we demonstrate that E. coli SSB drastically and reversibly compacts ssDNA templates upon changes in NaCl concentration. We also examine the interactions between a phosphomimetic RPA and ssDNA. Our results indicate that RPA-ssDNA interactions are not significantly altered by these modifications. We anticipate that low-complexity ssDNA curtains will be broadly useful for single-molecule studies of ssDNA-binding proteins involved in DNA replication, transcription, and repair.
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Affiliation(s)
- Jeffrey M. Schaub
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
| | - Hongshan Zhang
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
| | - Michael M. Soniat
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
| | - Ilya J. Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, United States
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28
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Phage Mu Gam protein promotes NHEJ in concert with Escherichia coli ligase. Proc Natl Acad Sci U S A 2018; 115:E11614-E11622. [PMID: 30487222 DOI: 10.1073/pnas.1816606115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The Gam protein of transposable phage Mu is an ortholog of eukaryotic and bacterial Ku proteins, which carry out nonhomologous DNA end joining (NHEJ) with the help of dedicated ATP-dependent ligases. Many bacteria carry Gam homologs associated with either complete or defective Mu-like prophages, but the role of Gam in the life cycle of Mu or in bacteria is unknown. Here, we show that MuGam is part of a two-component bacterial NHEJ DNA repair system. Ensemble and single-molecule experiments reveal that MuGam binds to DNA ends, slows the progress of RecBCD exonuclease, promotes binding of NAD+-dependent Escherichia coli ligase A, and stimulates ligation. In vivo, Gam equally promotes both precise and imprecise joining of restriction enzyme-digested linear plasmid DNA, as well as of a double-strand break (DSB) at an engineered I-SceI site in the chromosome. Cell survival after the induced DSB is specific to the stationary phase. In long-term growth competition experiments, particularly upon treatment with a clastogen, the presence of gam in a Mu lysogen confers a distinct fitness advantage. We also show that the role of Gam in the life of phage Mu is related not to transposition but to protection of genomic Mu copies from RecBCD when viral DNA packaging begins. Taken together, our data show that MuGam provides bacteria with an NHEJ system and suggest that the resulting fitness advantage is a reason that bacteria continue to retain the gam gene in the absence of an intact prophage.
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29
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Dillard KE, Brown MW, Johnson NV, Xiao Y, Dolan A, Hernandez E, Dahlhauser SD, Kim Y, Myler LR, Anslyn EV, Ke A, Finkelstein IJ. Assembly and Translocation of a CRISPR-Cas Primed Acquisition Complex. Cell 2018; 175:934-946.e15. [PMID: 30343903 DOI: 10.1016/j.cell.2018.09.039] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 07/20/2018] [Accepted: 09/18/2018] [Indexed: 12/18/2022]
Abstract
CRISPR-Cas systems confer an adaptive immunity against viruses. Following viral injection, Cas1-Cas2 integrates segments of the viral genome (spacers) into the CRISPR locus. In type I CRISPR-Cas systems, efficient "primed" spacer acquisition and viral degradation (interference) require both the Cascade complex and the Cas3 helicase/nuclease. Here, we present single-molecule characterization of the Thermobifida fusca (Tfu) primed acquisition complex (PAC). We show that TfuCascade rapidly samples non-specific DNA via facilitated one-dimensional diffusion. Cas3 loads at target-bound Cascade and the Cascade/Cas3 complex translocates via a looped DNA intermediate. Cascade/Cas3 complexes stall at diverse protein roadblocks, resulting in a double strand break at the stall site. In contrast, Cas1-Cas2 samples DNA transiently via 3D collisions. Moreover, Cas1-Cas2 associates with Cascade and translocates with Cascade/Cas3, forming the PAC. PACs can displace different protein roadblocks, suggesting a mechanism for long-range spacer acquisition. This work provides a molecular basis for the coordinated steps in CRISPR-based adaptive immunity.
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Affiliation(s)
- Kaylee E Dillard
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Maxwell W Brown
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Nicole V Johnson
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Yibei Xiao
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Adam Dolan
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Erik Hernandez
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Samuel D Dahlhauser
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Yoori Kim
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Logan R Myler
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Eric V Anslyn
- Department of Chemistry, University of Texas at Austin, Austin, TX 78712, USA
| | - Ailong Ke
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA.
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30
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Myler LR, Gallardo IF, Soniat MM, Deshpande RA, Gonzalez XB, Kim Y, Paull TT, Finkelstein IJ. Single-Molecule Imaging Reveals How Mre11-Rad50-Nbs1 Initiates DNA Break Repair. Mol Cell 2017; 67:891-898.e4. [PMID: 28867292 PMCID: PMC5609712 DOI: 10.1016/j.molcel.2017.08.002] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 06/07/2017] [Accepted: 08/04/2017] [Indexed: 11/21/2022]
Abstract
DNA double-strand break (DSB) repair is essential for maintaining our genomes. Mre11-Rad50-Nbs1 (MRN) and Ku70-Ku80 (Ku) direct distinct DSB repair pathways, but the interplay between these complexes at a DSB remains unclear. Here, we use high-throughput single-molecule microscopy to show that MRN searches for free DNA ends by one-dimensional facilitated diffusion, even on nucleosome-coated DNA. Rad50 binds homoduplex DNA and promotes facilitated diffusion, whereas Mre11 is required for DNA end recognition and nuclease activities. MRN gains access to occluded DNA ends by removing Ku or other DNA adducts via an Mre11-dependent nucleolytic reaction. Next, MRN loads exonuclease 1 (Exo1) onto the free DNA ends to initiate DNA resection. In the presence of replication protein A (RPA), MRN acts as a processivity factor for Exo1, retaining the exonuclease on DNA for long-range resection. Our results provide a mechanism for how MRN promotes homologous recombination on nucleosome-coated DNA.
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Affiliation(s)
- Logan R Myler
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ignacio F Gallardo
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Michael M Soniat
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Rajashree A Deshpande
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Xenia B Gonzalez
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Yoori Kim
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tanya T Paull
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Howard Hughes Medical Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA.
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31
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The more the merrier: high-throughput single-molecule techniques. Biochem Soc Trans 2017; 45:759-769. [PMID: 28620037 DOI: 10.1042/bst20160137] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 03/26/2017] [Accepted: 03/28/2017] [Indexed: 12/24/2022]
Abstract
The single-molecule approach seeks to understand molecular mechanisms by observing biomolecular processes at the level of individual molecules. These methods have led to a developing understanding that for many processes, a diversity of behaviours will be observed, representing a multitude of pathways. This realisation necessitates that an adequate number of observations are recorded to fully characterise this diversity. The requirement for large numbers of observations to adequately sample distributions, subpopulations, and rare events presents a significant challenge for single-molecule techniques, which by their nature do not typically provide very high throughput. This review will discuss many developing techniques which address this issue by combining nanolithographic approaches, such as zero-mode waveguides and DNA curtains, with single-molecule fluorescence microscopy, and by drastically increasing throughput of force-based approaches such as magnetic tweezers and laminar-flow techniques. These methods not only allow the collection of large volumes of single-molecule data in single experiments, but have also made improvements to ease-of-use, accessibility, and automation of data analysis.
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32
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Larson AG, Elnatan D, Keenen MM, Trnka MJ, Johnston JB, Burlingame AL, Agard DA, Redding S, Narlikar GJ. Liquid droplet formation by HP1α suggests a role for phase separation in heterochromatin. Nature 2017; 547:236-240. [PMID: 28636604 PMCID: PMC5606208 DOI: 10.1038/nature22822] [Citation(s) in RCA: 1109] [Impact Index Per Article: 158.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 05/16/2017] [Indexed: 01/15/2023]
Abstract
Gene silencing by heterochromatin is proposed to occur in part as a result of the ability of heterochromatin protein 1 (HP1) proteins to spread across large regions of the genome, compact the underlying chromatin and recruit diverse ligands. Here we identify a new property of the human HP1α protein: the ability to form phase-separated droplets. While unmodified HP1α is soluble, either phosphorylation of its N-terminal extension or DNA binding promotes the formation of phase-separated droplets. Phosphorylation-driven phase separation can be promoted or reversed by specific HP1α ligands. Known components of heterochromatin such as nucleosomes and DNA preferentially partition into the HP1α droplets, but molecules such as the transcription factor TFIIB show no preference. Using a single-molecule DNA curtain assay, we find that both unmodified and phosphorylated HP1α induce rapid compaction of DNA strands into puncta, although with different characteristics. We show by direct protein delivery into mammalian cells that an HP1α mutant incapable of phase separation in vitro forms smaller and fewer nuclear puncta than phosphorylated HP1α. These findings suggest that heterochromatin-mediated gene silencing may occur in part through sequestration of compacted chromatin in phase-separated HP1 droplets, which are dissolved or formed by specific ligands on the basis of nuclear context.
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Affiliation(s)
- Adam G. Larson
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Daniel Elnatan
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Madeline M. Keenen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Michael J. Trnka
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jonathan B. Johnston
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alma L. Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - David A. Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
- Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Sy Redding
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Geeta J. Narlikar
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
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Kim Y, de la Torre A, Leal AA, Finkelstein IJ. Efficient modification of λ-DNA substrates for single-molecule studies. Sci Rep 2017; 7:2071. [PMID: 28522818 PMCID: PMC5437064 DOI: 10.1038/s41598-017-01984-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 04/05/2017] [Indexed: 01/15/2023] Open
Abstract
Single-molecule studies of protein-nucleic acid interactions frequently require site-specific modification of long DNA substrates. The bacteriophage λ is a convenient source of high quality long (48.5 kb) DNA. However, introducing specific sequences, tertiary structures, and chemical modifications into λ-DNA remains technically challenging. Most current approaches rely on multi-step ligations with low yields and incomplete products. Here, we describe a molecular toolkit for rapid preparation of modified λ-DNA. A set of PCR cassettes facilitates the introduction of recombinant DNA sequences into the λ-phage genome with 90-100% yield. Extrahelical structures and chemical modifications can be inserted at user-defined sites via an improved nicking enzyme-based strategy. As a proof-of-principle, we explore the interactions of S. cerevisiae Proliferating Cell Nuclear Antigen (yPCNA) with modified DNA sequences and structures incorporated within λ-DNA. Our results demonstrate that S. cerevisiae Replication Factor C (yRFC) can load yPCNA onto 5'-ssDNA flaps, (CAG)13 triplet repeats, and homoduplex DNA. However, yPCNA remains trapped on the (CAG)13 structure, confirming a proposed mechanism for triplet repeat expansion. We anticipate that this molecular toolbox will be broadly useful for other studies that require site-specific modification of long DNA substrates.
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Affiliation(s)
- Yoori Kim
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, 78712, USA
| | - Armando de la Torre
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, 78712, USA
| | - Andrew A Leal
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, 78712, USA.
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas, 78712, USA.
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The mismatch repair and meiotic recombination endonuclease Mlh1-Mlh3 is activated by polymer formation and can cleave DNA substrates in trans. PLoS Biol 2017; 15:e2001164. [PMID: 28453523 PMCID: PMC5409509 DOI: 10.1371/journal.pbio.2001164] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 03/31/2017] [Indexed: 01/21/2023] Open
Abstract
Crossing over between homologs is initiated in meiotic prophase by the formation of DNA double-strand breaks that occur throughout the genome. In the major interference-responsive crossover pathway in baker’s yeast, these breaks are resected to form 3' single-strand tails that participate in a homology search, ultimately forming double Holliday junctions (dHJs) that primarily include both homologs. These dHJs are resolved by endonuclease activity to form exclusively crossovers, which are critical for proper homolog segregation in Meiosis I. Recent genetic, biochemical, and molecular studies in yeast are consistent with the hypothesis of Mlh1-Mlh3 DNA mismatch repair complex acting as the major endonuclease activity that resolves dHJs into crossovers. However, the mechanism by which the Mlh1-Mlh3 endonuclease is activated is unknown. Here, we provide evidence that Mlh1-Mlh3 does not behave like a structure-specific endonuclease but forms polymers required to generate nicks in DNA. This conclusion is supported by DNA binding studies performed with different-sized substrates that contain or lack polymerization barriers and endonuclease assays performed with varying ratios of endonuclease-deficient and endonuclease-proficient Mlh1-Mlh3. In addition, Mlh1-Mlh3 can generate religatable double-strand breaks and form an active nucleoprotein complex that can nick DNA substrates in trans. Together these observations argue that Mlh1-Mlh3 may not act like a canonical, RuvC-like Holliday junction resolvase and support a novel model in which Mlh1-Mlh3 is loaded onto DNA to form an activated polymer that cleaves DNA. In sexually reproducing organisms, crossing over between homologous chromosomes in meiosis creates physical linkages required to segregate chromosomes into haploid gametes. In baker’s yeast, which utilizes meiotic recombination pathways conserved in mice and humans, the majority of meiotic crossovers are initiated through the formation of a branched DNA intermediate, which is stabilized by the Msh4-Msh5 complex. This DNA intermediate is further processed to form a structure (a double Holliday junction), which requires the endonuclease activity of the Mlh1-Mlh3 DNA mismatch repair factor to be resolved exclusively into a crossover product. Current meiotic recombination models invoke the use of structure-specific enzymes that symmetrically cleave single Holliday junctions. In this study, we provide evidence that the yeast Mlh1-Mlh3 complex is unlikely to act as a structure-specific enzyme. Furthermore, we showed that Mlh1-Mlh3’s endonuclease activity is dependent upon its ability to form a polymer on DNA and suggest that it is capable of cleaving DNA that is captured in an active complex. Together, our biochemical observations support a novel model involving regulated polymerization of Mlh1-Mlh3 for its cleavage function, potentially in meiotic crossovers or in mismatch repair.
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35
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Soniat MM, Myler LR, Schaub JM, Kim Y, Gallardo IF, Finkelstein IJ. Next-Generation DNA Curtains for Single-Molecule Studies of Homologous Recombination. Methods Enzymol 2017; 592:259-281. [PMID: 28668123 PMCID: PMC5564670 DOI: 10.1016/bs.mie.2017.03.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Homologous recombination (HR) is a universally conserved DNA double-strand break repair pathway. Single-molecule fluorescence imaging approaches have revealed new mechanistic insights into nearly all aspects of HR. These methods are especially suited for studying protein complexes because multicolor fluorescent imaging can parse out subassemblies and transient intermediates that associate with the DNA substrates on the millisecond to hour timescales. However, acquiring single-molecule datasets remains challenging because most of these approaches are designed to measure one molecular reaction at a time. The DNA curtains platform facilitates high-throughput single-molecule imaging by organizing arrays of DNA molecules on the surface of a microfluidic flowcell. Here, we describe a second-generation UV lithography-based protocol for fabricating flowcells for DNA curtains. This protocol greatly reduces the challenges associated with assembling DNA curtains and paves the way for the rapid acquisition of large datasets from individual single-molecule experiments. Drawing on our recent studies of human HR, we also provide an overview of how DNA curtains can be used for observing facilitated protein diffusion, processive enzyme translocation, and nucleoprotein filament dynamics on single-stranded DNA. Together, these protocols and case studies form a comprehensive introduction for other researchers that may want to adapt DNA curtains for high-throughput single-molecule studies of DNA replication, transcription, and repair.
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Affiliation(s)
- Michael M Soniat
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Logan R Myler
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Jeffrey M Schaub
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Yoori Kim
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Ignacio F Gallardo
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States
| | - Ilya J Finkelstein
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, United States; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, United States.
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Inserting Extrahelical Structures into Long DNA Substrates for Single-Molecule Studies of DNA Mismatch Repair. Methods Enzymol 2016; 582:221-238. [PMID: 28062036 DOI: 10.1016/bs.mie.2016.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The DNA mismatch repair (MMR) system corrects errors that occur during DNA replication. MMR needs the coordinated and highly dynamic assembly of repair enzymes at the site of the lesion. By visualizing transient intermediates of these assemblies, single-molecule approaches have shed critical insights into the mechanisms of MMR. These studies frequently require long (>20kb) DNA substrates with lesions and other extrahelical structures inserted at defined positions. DNA derived from bacteriophage λ (λ-DNA) is a high quality long (48.5kb) DNA substrate that is frequently used in single-molecule studies. Here we provide detailed protocols for site-specific incorporation of recombinant sequences and extrahelical structures into λ-DNA. We also describe how to assemble DNA curtains, and how to collect and analyze single-molecule observations of lesion recognition by MMR proteins diffusing on these DNA curtains. These protocols will facilitate future single-molecule studies of DNA transcription, replication, and repair.
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Myler LR, Finkelstein IJ. Eukaryotic resectosomes: A single-molecule perspective. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 127:119-129. [PMID: 27498169 DOI: 10.1016/j.pbiomolbio.2016.08.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/02/2016] [Indexed: 12/13/2022]
Abstract
DNA double-strand breaks (DSBs) disrupt the physical and genetic continuity of the genome. If unrepaired, DSBs can lead to cellular dysfunction and malignant transformation. Homologous recombination (HR) is a universally conserved DSB repair mechanism that employs the information in a sister chromatid to catalyze error-free DSB repair. To initiate HR, cells assemble the resectosome: a multi-protein complex composed of helicases, nucleases, and regulatory proteins. The resectosome nucleolytically degrades (resects) the free DNA ends for downstream homologous recombination. Several decades of intense research have identified the core resectosome components in eukaryotes, archaea, and bacteria. More recently, these proteins have been characterized via single-molecule approaches. Here, we focus on recent single-molecule studies that have begun to unravel how nucleases, helicases, processivity factors, and other regulatory proteins dictate the extent and efficiency of DNA resection in eukaryotic cells. We conclude with a discussion of outstanding questions that can be addressed via single-molecule approaches.
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Affiliation(s)
- Logan R Myler
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, 78712, USA.
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Brown MW, Kim Y, Williams GM, Huck JD, Surtees JA, Finkelstein IJ. Dynamic DNA binding licenses a repair factor to bypass roadblocks in search of DNA lesions. Nat Commun 2016; 7:10607. [PMID: 26837705 PMCID: PMC4742970 DOI: 10.1038/ncomms10607] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/04/2016] [Indexed: 12/17/2022] Open
Abstract
DNA-binding proteins search for specific targets via facilitated diffusion along a crowded genome. However, little is known about how crowded DNA modulates facilitated diffusion and target recognition. Here we use DNA curtains and single-molecule fluorescence imaging to investigate how Msh2-Msh3, a eukaryotic mismatch repair complex, navigates on crowded DNA. Msh2-Msh3 hops over nucleosomes and other protein roadblocks, but maintains sufficient contact with DNA to recognize a single lesion. In contrast, Msh2-Msh6 slides without hopping and is largely blocked by protein roadblocks. Remarkably, the Msh3-specific mispair-binding domain (MBD) licences a chimeric Msh2-Msh6(3MBD) to bypass nucleosomes. Our studies contrast how Msh2-Msh3 and Msh2-Msh6 navigate on a crowded genome and suggest how Msh2-Msh3 locates DNA lesions outside of replication-coupled repair. These results also provide insights into how DNA repair factors search for DNA lesions in the context of chromatin.
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Affiliation(s)
- Maxwell W Brown
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Yoori Kim
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Gregory M Williams
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | - John D Huck
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | - Jennifer A Surtees
- Department of Biochemistry, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214, USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.,Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, Texas 78712, USA
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