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Ramakrishnan S, Subramaniam S, Kielar C, Grundmeier G, Stewart AF, Keller A. Protein-Assisted Room-Temperature Assembly of Rigid, Immobile Holliday Junctions and Hierarchical DNA Nanostructures. Molecules 2020; 25:molecules25215099. [PMID: 33153073 PMCID: PMC7663122 DOI: 10.3390/molecules25215099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 12/30/2022] Open
Abstract
Immobile Holliday junctions represent not only the most fundamental building block of structural DNA nanotechnology but are also of tremendous importance for the in vitro investigation of genetic recombination and epigenetics. Here, we present a detailed study on the room-temperature assembly of immobile Holliday junctions with the help of the single-strand annealing protein Redβ. Individual DNA single strands are initially coated with protein monomers and subsequently hybridized to form a rigid blunt-ended four-arm junction. We investigate the efficiency of this approach for different DNA/protein ratios, as well as for different DNA sequence lengths. Furthermore, we also evaluate the potential of Redβ to anneal sticky-end modified Holliday junctions into hierarchical assemblies. We demonstrate the Redβ-mediated annealing of Holliday junction dimers, multimers, and extended networks several microns in size. While these hybrid DNA–protein nanostructures may find applications in the crystallization of DNA–protein complexes, our work shows the great potential of Redβ to aid in the synthesis of functional DNA nanostructures under mild reaction conditions.
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Affiliation(s)
- Saminathan Ramakrishnan
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098 Paderborn, Germany; (S.R.); (C.K.); (G.G.)
- Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Sivaraman Subramaniam
- Biotechnology Center, Department of Genomics, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany; (S.S.); (A.F.S.)
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01062 Dresden, Germany
| | - Charlotte Kielar
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098 Paderborn, Germany; (S.R.); (C.K.); (G.G.)
| | - Guido Grundmeier
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098 Paderborn, Germany; (S.R.); (C.K.); (G.G.)
| | - A. Francis Stewart
- Biotechnology Center, Department of Genomics, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany; (S.S.); (A.F.S.)
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01062 Dresden, Germany
| | - Adrian Keller
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098 Paderborn, Germany; (S.R.); (C.K.); (G.G.)
- Correspondence:
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Xu K, Stewart AF, Porter AC. Stimulation of oligonucleotide-directed gene correction by Redβ expression and MSH2 depletion in human HT1080 cells. Mol Cells 2015; 38:33-9. [PMID: 25431426 PMCID: PMC4314130 DOI: 10.14348/molcells.2015.2163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 01/30/2023] Open
Abstract
The correction of disease-causing mutations by single-strand oligonucleotide-templated DNA repair (ssOR) is an attractive approach to gene therapy, but major improvements in ssOR efficiency and consistency are needed. The mechanism of ssOR is poorly understood but may involve annealing of oligonucleotides to transiently exposed single-stranded regions in the target duplex. In bacteria and yeast it has been shown that ssOR is promoted by expression of Redβ, a single-strand DNA annealing protein from bacteriophage lambda. Here we show that Redβ expression is well tolerated in a human cell line where it consistently promotes ssOR. By use of short interfering RNA, we also show that ssOR is stimulated by the transient depletion of the endogenous DNA mismatch repair protein MSH2. Furthermore, we find that the effects of Redβ expression and MSH2 depletion on ssOR can be combined with a degree of cooperativity. These results suggest that oligonucleotide annealing and mismatch recognition are distinct but interdependent events in ssOR that can be usefully modulated in gene correction strategies.
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Affiliation(s)
- Ke Xu
- Tianjin Key Laboratory of Lung Cancer Metastasis and Tumor Microenviroment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin 300052,
China
- Gene Targeting Group, Department of Hematology, Faculty of Medicine, Imperial College London, London W12 0NN,
UK
| | - A. Francis Stewart
- Genomics, Bio Innovations Zentrum, Technische Universitaet Dresden, 01307 Dresden,
Germany
| | - Andrew C.G. Porter
- Gene Targeting Group, Department of Hematology, Faculty of Medicine, Imperial College London, London W12 0NN,
UK
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