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Fan L, Chong X, Zhao M, Jia F, Wang Z, Zhou Y, Lu X, Huang Q, Li P, Yang Y, Hu Z, Li Q, Zhang X, Shen L. Ultrasensitive Gastric Cancer Circulating Tumor Cellular CLDN18.2 RNA Detection Based on a Molecular Beacon. Anal Chem 2020; 93:665-670. [DOI: 10.1021/acs.analchem.0c04055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Linyang Fan
- School of Life Science, Beijing Institute of Technology, Beijing 100081, P. R. China
| | - Xiaoyi Chong
- Department of Gastrointestinal Oncology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China
| | - Minzhi Zhao
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Fei Jia
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Zihua Wang
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Ying Zhou
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Xiao Lu
- Department of Gastrointestinal Oncology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China
| | - Qiongrong Huang
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Ping Li
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Yanlian Yang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Zhiyuan Hu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, China
- School of Nanoscience and Technology, Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, P. R. China
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, Fujian 350122, China
| | - Qin Li
- School of Life Science, Beijing Institute of Technology, Beijing 100081, P. R. China
| | - Xiaotian Zhang
- Department of Gastrointestinal Oncology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China
| | - Lin Shen
- Department of Gastrointestinal Oncology, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Peking University Cancer Hospital & Institute, 52 Fucheng Road, Beijing 100142, China
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2
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Mao S, Ying Y, Wu R, Chen AK. Recent Advances in the Molecular Beacon Technology for Live-Cell Single-Molecule Imaging. iScience 2020; 23:101801. [PMID: 33299972 PMCID: PMC7702005 DOI: 10.1016/j.isci.2020.101801] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nucleic acids, aside from being best known as the carrier of genetic information, are versatile biomaterials for constructing nanoscopic devices for biointerfacing, owing to their unique properties such as specific base pairing and predictable structure. For live-cell analysis of native RNA transcripts, the most widely used nucleic acid-based nanodevice has been the molecular beacon (MB), a class of stem-loop-forming probes that is activated to fluoresce upon hybridization with target RNA. Here, we overview efforts that have been made in developing MB-based bioassays for sensitive intracellular analysis, particularly at the single-molecule level. We also describe challenges that are currently limiting the widespread use of MBs and provide possible solutions. With continued refinement of MBs in terms of labeling specificity and detection accuracy, accompanied by new development in imaging platforms with unprecedented sensitivity, the application of MBs is envisioned to expand in various biological research fields.
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Affiliation(s)
- Shiqi Mao
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
| | - Yachen Ying
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
| | - Ruonan Wu
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
| | - Antony K. Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China
- Corresponding author
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3
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Feng X, Kang W, Wu X, Wang S, Liu F. Quantitative Detection and Real-Time Monitoring of Endogenous mRNA at the Single Live Cell Level Using a Ratiometric Molecular Beacon. ACS APPLIED MATERIALS & INTERFACES 2019; 11:28752-28761. [PMID: 31329405 DOI: 10.1021/acsami.9b12394] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Messenger ribonucleic acid (mRNA) plays an important role in various cellular processes. however, traditional techniques cannot realize mRNA detections in live cells as they rely on mRNA purification or cell fixation. To achieve real-time and quantitative mRNA detections at a single live cell level, a single-strand stem-loop-structured ratiometric molecular beacon (RMB) composed of the phosphorothioate-modified loop domain on the 2'-O-methyl RNA backbone with a reporter dye, quencher, and reference dye is proposed to detect the Hsp27 mRNA as a modeled endogenous mRNA. When the RMB hybridizes with the target, the stem-loop structure opens, causing separation of the reporter dye and the quencher and restores the reporter fluorescent signals; therefore, the Hsp27 mRNA can be quantitatively detected according to the ratio of the reporter fluorescent signal to the reference fluorescent signal. Both the phosphorothioate and 2'-O-methyl RNA modifications obviously reduce the nonspecific opening, and the additional reference dye ensures the detection precision using co-localization analysis. Not only does this remove the false-positive signal caused by the nuclease degradation-generated RMB fragment, but it also corrects variations caused by direct measurement of reporter fluorescence intensities at a single cell level owing to inhomogeneity in probe delivery. The designed RMB could detect the Hsp27 mRNA with high signal-to-noise ratio and sensitivity as well as excellent specificity and antidegradation capability proved in vitro and in live cells. Furthermore, it was successfully adopted in subcellular localization, quantitative copy number measurements, and even real-time monitoring of Hsp27 mRNA in live cells, demonstrating that the proposed RMB can be a potential quantitative endogenous mRNA detection tool, especially at a single live cell level.
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Affiliation(s)
- Xufei Feng
- Joint International Research Laboratory of Animal Health and Food Safety & Single Molecule Nanometry Laboratory (Sinmolab) , Nanjing Agricultural University , Nanjing 210095 , China
| | - Wenjie Kang
- Joint International Research Laboratory of Animal Health and Food Safety & Single Molecule Nanometry Laboratory (Sinmolab) , Nanjing Agricultural University , Nanjing 210095 , China
| | - Xuping Wu
- The Second Hospital of Nanjing , Nanjing University of Chinese Medicine , Nanjing 210003 , China
| | - Shouyu Wang
- Joint International Research Laboratory of Animal Health and Food Safety & Single Molecule Nanometry Laboratory (Sinmolab) , Nanjing Agricultural University , Nanjing 210095 , China
- Computational Optics Laboratory, School of Science , Jiangnan University , Wuxi , Jiangsu 214122 , China
| | - Fei Liu
- Joint International Research Laboratory of Animal Health and Food Safety & Single Molecule Nanometry Laboratory (Sinmolab) , Nanjing Agricultural University , Nanjing 210095 , China
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4
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Stewart MP, Langer R, Jensen KF. Intracellular Delivery by Membrane Disruption: Mechanisms, Strategies, and Concepts. Chem Rev 2018; 118:7409-7531. [PMID: 30052023 PMCID: PMC6763210 DOI: 10.1021/acs.chemrev.7b00678] [Citation(s) in RCA: 399] [Impact Index Per Article: 66.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intracellular delivery is a key step in biological research and has enabled decades of biomedical discoveries. It is also becoming increasingly important in industrial and medical applications ranging from biomanufacture to cell-based therapies. Here, we review techniques for membrane disruption-based intracellular delivery from 1911 until the present. These methods achieve rapid, direct, and universal delivery of almost any cargo molecule or material that can be dispersed in solution. We start by covering the motivations for intracellular delivery and the challenges associated with the different cargo types-small molecules, proteins/peptides, nucleic acids, synthetic nanomaterials, and large cargo. The review then presents a broad comparison of delivery strategies followed by an analysis of membrane disruption mechanisms and the biology of the cell response. We cover mechanical, electrical, thermal, optical, and chemical strategies of membrane disruption with a particular emphasis on their applications and challenges to implementation. Throughout, we highlight specific mechanisms of membrane disruption and suggest areas in need of further experimentation. We hope the concepts discussed in our review inspire scientists and engineers with further ideas to improve intracellular delivery.
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Affiliation(s)
- Martin P. Stewart
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
- The Koch Institute for Integrative Cancer Research,
Massachusetts Institute of Technology, Cambridge, USA
| | - Robert Langer
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
- The Koch Institute for Integrative Cancer Research,
Massachusetts Institute of Technology, Cambridge, USA
| | - Klavs F. Jensen
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
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5
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Abstract
Conventional molecular beacons (MBs) have been used extensively for imaging specific endogenous RNAs in living cells, but their tendency to generate false-positive signals as a result of nuclease degradation and/or nonspecific binding limits sensitive and accurate imaging of intracellular RNAs. In an attempt to overcome this limitation, MBs have been synthesized with various chemically modified oligonucleotide backbones to confer greater biostability. We have recently developed a new MB architecture composed of 2'-O-methyl RNA (2Me), a fully phosphorothioate (PS) modified loop domain and a phosphodiester stem (2Me/PSLOOP MB). We showed that this new MB exhibits a marginal level of false-positive signals and enables accurate single-molecule imaging of target RNA in living cells. In this chapter, we describe detailed methods that led us to conclude that, among various PS-modified configurations, the 2Me/PSLOOP MB is an optimal design for intracellular RNA analysis.
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6
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Ma Z, Wu X, Krueger CJ, Chen AK. Engineering Novel Molecular Beacon Constructs to Study Intracellular RNA Dynamics and Localization. GENOMICS PROTEOMICS & BIOINFORMATICS 2017; 15:279-286. [PMID: 28942262 PMCID: PMC5673673 DOI: 10.1016/j.gpb.2017.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 04/08/2017] [Accepted: 04/17/2017] [Indexed: 11/25/2022]
Abstract
With numerous advancements in novel biochemical techniques, our knowledge of the role of RNAs in the regulation of cellular physiology and pathology has grown significantly over the past several decades. Nevertheless, detailed information regarding RNA processing, trafficking, and localization in living cells has been lacking due to technical limitations in imaging single RNA transcripts in living cells with high spatial and temporal resolution. In this review, we discuss techniques that have shown great promise for single RNA imaging, followed by highlights in our recent work in the development of molecular beacons (MBs), a class of nanoscale oligonucleotide-probes, for detecting individual RNA transcripts in living cells. With further refinement of MB design and development of more sophisticated fluorescence microscopy techniques, we envision that MB-based approaches could promote new discoveries of RNA functions and activities.
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Affiliation(s)
- Zhao Ma
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Xiaotian Wu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Christopher J Krueger
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China; Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Antony K Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China.
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7
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Chen M, Ma Z, Wu X, Mao S, Yang Y, Tan J, Krueger CJ, Chen AK. A molecular beacon-based approach for live-cell imaging of RNA transcripts with minimal target engineering at the single-molecule level. Sci Rep 2017; 7:1550. [PMID: 28484218 PMCID: PMC5431543 DOI: 10.1038/s41598-017-01740-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 04/18/2017] [Indexed: 12/27/2022] Open
Abstract
Analysis of RNA dynamics and localization at the single-molecule level in living cells has been predominantly achieved by engineering target RNAs with large insertions of tandem repeat sequences that are bound by protein-based or oligonucleotide-based fluorescent probes. Thus, individual RNAs are tagged by multiple fluorescent probes, making them detectable by fluorescence microscopy. Since large insertions may affect RNA processes including trafficking and localization, here we present a strategy to visualize single RNA transcripts in living cells using molecular beacons (MBs) - fluorogenic oligonucleotide probes - with minimal target engineering. The MBs are composed of 2′-O-methyl RNAs with a fully phosphorothioate-modified loop domain (2Me/PSLOOP MBs), an architecture that elicits marginal levels of nonspecific signals in cells. We showed that MBs can detect single transcripts containing as few as 8 target repeat sequences with ~90% accuracy. In both the nucleus and the cytoplasm, mRNAs harboring 8 repeats moved faster than those with 32 repeats, suggesting that intracellular activities are less impeded by smaller engineered insertions. We then report the first MB-based imaging of intracellular dynamics and localization of single long noncoding RNAs (lncRNAs). We envision the proposed minimally-engineered, MB-based technology for live-cell single-molecule RNA imaging could facilitate new discoveries in RNA research.
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Affiliation(s)
- Mingming Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Zhao Ma
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Xiaotian Wu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Shiqi Mao
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Yantao Yang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Jie Tan
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Christopher J Krueger
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China.,Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Antony K Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China.
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8
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Monitoring integrity and localization of modified single-stranded RNA oligonucleotides using ultrasensitive fluorescence methods. PLoS One 2017; 12:e0173401. [PMID: 28278199 PMCID: PMC5344492 DOI: 10.1371/journal.pone.0173401] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 02/20/2017] [Indexed: 12/20/2022] Open
Abstract
Short single-stranded oligonucleotides represent a class of promising therapeutics with diverse application areas. Antisense oligonucleotides, for example, can interfere with various processes involved in mRNA processing through complementary base pairing. Also RNA interference can be regulated by antagomirs, single-stranded siRNA and single-stranded microRNA mimics. The increased susceptibility to nucleolytic degradation of unpaired RNAs can be counteracted by chemical modification of the sugar phosphate backbone. In order to understand the dynamics of such single-stranded RNAs, we investigated their fate after exposure to cellular environment by several fluorescence spectroscopy techniques. First, we elucidated the degradation of four differently modified, dual-dye labeled short RNA oligonucleotides in HeLa cell extracts by fluorescence correlation spectroscopy, fluorescence cross-correlation spectroscopy and Förster resonance energy transfer. We observed that the integrity of the oligonucleotide sequence correlates with the extent of chemical modifications. Furthermore, the data showed that nucleolytic degradation can only be distinguished from unspecific effects like aggregation, association with cellular proteins, or intramolecular dynamics when considering multiple measurement and analysis approaches. We also investigated the localization and integrity of the four modified oligonucleotides in cultured HeLa cells using fluorescence lifetime imaging microscopy. No intracellular accumulation could be observed for unmodified oligonucleotides, while completely stabilized oligonucleotides showed strong accumulation within HeLa cells with no changes in fluorescence lifetime over 24 h. The integrity and accumulation of partly modified oligonucleotides was in accordance with their extent of modification. In highly fluorescent cells, the oligonucleotides were transported to the nucleus. The lifetime of the RNA in the cells could be explained by a balance between release of the oligonucleotides from endosomes, degradation by RNases and subsequent depletion from the cells.
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9
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Zhao D, Yang Y, Qu N, Chen M, Ma Z, Krueger CJ, Behlke MA, Chen AK. Single-molecule detection and tracking of RNA transcripts in living cells using phosphorothioate-optimized 2'-O-methyl RNA molecular beacons. Biomaterials 2016; 100:172-83. [PMID: 27261815 DOI: 10.1016/j.biomaterials.2016.05.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 05/10/2016] [Accepted: 05/17/2016] [Indexed: 12/11/2022]
Abstract
Molecular Beacons (MBs) composed of 2'-O-methyl RNA (2Me) and phosphorothioate (PS) linkages throughout the backbone (2Me/PSFULL MBs) have enabled long-term imaging of RNA in living cells, but excess PS modification can induce nonspecific binding, causing false-positive signals. In this study, we evaluate the intracellular stability of MBs composed of 2Me with various PS modifications, and found that false-positive signals could be reduced to marginal levels when the MBs possess a fully PS-modified loop domain and a phosphodiester stem (2Me/PSLOOP MB). Additionally, 2Me/PSLOOP MBs exhibited uncompromised hybridization kinetics, prolonged functionality and >88% detection accuracy for single RNA transcripts, and could do so without interfering with gene expression or cell growth. Finally, 2Me/PSLOOP MBs could image the dynamics of single mRNA transcripts in the nucleus and the cytoplasm simultaneously, regardless of whether the MBs targeted the 5'- or the 3'-UTR. Together, these findings demonstrate the effectiveness of loop-domain PS modification in reducing nonspecific signals and the potential for sensitive and accurate imaging of individual RNAs at the single-molecule level. With the growing interest in the role of RNA localization and dynamics in health and disease, 2Me/PSLOOP MBs could enable new discoveries in RNA research.
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Affiliation(s)
- Dan Zhao
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Yantao Yang
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Na Qu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Mingming Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Zhao Ma
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Christopher J Krueger
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Mark A Behlke
- Integrated DNA Technologies Inc., Coralville, IA, 52241, USA
| | - Antony K Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China.
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10
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2'-O-methyl nucleotide modified DNA substrates influence the cleavage efficiencies of BamHI and BglII. J Biosci 2015; 39:621-30. [PMID: 25116617 DOI: 10.1007/s12038-014-9466-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Induction of endonucleolytic DNA cleavage is an essential event that links the initiating stimuli to the final effects of cells. The cleavage efficiency and thus the final yield could be affected by many factors, including structures of DNA substrates, composite structures of enzymes-substrates or enzymes-nucleic analogs and so on. However, it is not clear whether a nucleotide derivative-substituted in DNA substrates can influence the efficiency of enzymatic cleavage. To investigate the effect of sugar pucker conformation on DNA-protein interactions, we used 2'-O-methyl modified nucleotides (OMeN) to modify DNA substrates of isocaudemers BamHI and BglII in this study, and used FRET assay as an efficient method for analysis of enzyme cleavage. Experimental results demonstrated that OMeN-substituted recognition sequences influenced the cleavage rates significantly in a position-dependent manner. OMeN substitutions can reduce the cleavage as expected. Surprisingly, OMeN substitutions can also enhance the cleavage rates. The kinetics parameters of Vmax and Km have been obtained by fitting the Michaelis-Menten kinetic equation. These 2'- OMe nucleotides could behave as a regulatory element to modulate the enzymatic activity in vitro, and this property could enrich our understanding about the endonuclease cleavage mechanism and enhance our ability to regulate the enzymatic cleavage efficiency for applications in synthetic biology.
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11
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Zhao X, Liu B, Yan J, Yuan Y, An L, Guan Y. Structure variations of TBA G-quadruplex induced by 2'-O-methyl nucleotide in K+ and Ca2+ environments. Acta Biochim Biophys Sin (Shanghai) 2014; 46:837-50. [PMID: 25246433 DOI: 10.1093/abbs/gmu077] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Thrombin binding aptamer (TBA), a 15-mer oligonucleotide of d(GGTTGGTGTGGTTGG) sequence, folds into a chair-type antiparallel G-quadruplex in the K(+) environment, and each of two G-tetrads is characterized by a syn-anti-syn-anti glycosidic conformation arrangement. To explore its folding topology and structural stability, 2'-O-methyl nucleotide (OMe) with the C3'-endo sugar pucker conformation and anti glycosidic angle was used to selectively substitute for the guanine residues of G-tetrads of TBA, and these substituted TBAs were characterized using a circular dichroism spectrum, thermally differential spectrum, ultraviolet stability analysis, electrophoresis mobility shift assay, and thermodynamic analysis in K(+) and Ca(2+) environments. Results showed that single substitutions for syn-dG residues destabilized the G-quadruplex structure, while single substitutions for anti-dG residues could preserve the G-quadruplex in the K(+) environment. When one or two G-tetrads were modified with OMe, TBA became unstructured. In contrast, in Ca(2+) environment, the native TBA appeared to be unstructured. When two G-tetrads were substituted with OMe, TBA seemed to become a more stable parallel G-4 structure. Further thermodynamic data suggested that OMe-substitutions were an enthalpy-driven event. The results in this study enrich our understanding about the effects of nucleotide derivatives on the G-quadruplex structure stability in different ionic environments, which will help to design G-quadruplex for biological and medical applications.
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Affiliation(s)
- Xiaoyang Zhao
- Key Laboratory of Medical Cell Biology, Ministry of Education, Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110001, China Department of Chemistry, Shenyang Medical College, Shenyang 110034, China
| | - Bo Liu
- Key Laboratory of Medical Cell Biology, Ministry of Education, Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110001, China
| | - Jing Yan
- Key Laboratory of Medical Cell Biology, Ministry of Education, Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110001, China
| | - Ying Yuan
- Key Laboratory of Medical Cell Biology, Ministry of Education, Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110001, China
| | - Liwen An
- Key Laboratory of Medical Cell Biology, Ministry of Education, Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110001, China
| | - Yifu Guan
- Key Laboratory of Medical Cell Biology, Ministry of Education, Department of Biochemistry and Molecular Biology, China Medical University, Shenyang 110001, China
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12
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Alami NH, Smith RB, Carrasco MA, Williams LA, Winborn CS, Han SSW, Kiskinis E, Winborn B, Freibaum BD, Kanagaraj A, Clare AJ, Badders NM, Bilican B, Chaum E, Chandran S, Shaw CE, Eggan KC, Maniatis T, Taylor JP. Axonal transport of TDP-43 mRNA granules is impaired by ALS-causing mutations. Neuron 2014; 81:536-543. [PMID: 24507191 PMCID: PMC3939050 DOI: 10.1016/j.neuron.2013.12.018] [Citation(s) in RCA: 469] [Impact Index Per Article: 46.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2013] [Indexed: 12/13/2022]
Abstract
The RNA-binding protein TDP-43 regulates RNA metabolism at multiple levels, including transcription, RNA splicing, and mRNA stability. TDP-43 is a major component of the cytoplasmic inclusions characteristic of amyotrophic lateral sclerosis and some types of frontotemporal lobar degeneration. The importance of TDP-43 in disease is underscored by the fact that dominant missense mutations are sufficient to cause disease, although the role of TDP-43 in pathogenesis is unknown. Here we show that TDP-43 forms cytoplasmic mRNP granules that undergo bidirectional, microtubule-dependent transport in neurons in vitro and in vivo and facilitate delivery of target mRNA to distal neuronal compartments. TDP-43 mutations impair this mRNA transport function in vivo and in vitro, including in stem cell-derived motor neurons from ALS patients bearing any one of three different TDP-43 ALS-causing mutations. Thus, TDP-43 mutations that cause ALS lead to partial loss of a novel cytoplasmic function of TDP-43.
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Affiliation(s)
- Nael H. Alami
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Rebecca B. Smith
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Monica A. Carrasco
- Department of Biochemistry and Molecular Biophysics,
Columbia University Medical Center, New York, NY 10032, USA
| | - Luis A. Williams
- Department of Stem Cell and Regenerative Biology, Harvard
University, Cambridge, MA 02138
| | - Christina S. Winborn
- Department of Ophthalmology, University of Tennessee Health
Sciences Center, Memphis, TN 38163, USA
| | - Steve S. W. Han
- Department of Stem Cell and Regenerative Biology, Harvard
University, Cambridge, MA 02138
- Department of Neurology, Massachusetts General Hospital,
Boston, MA 02114, USA
| | - Evangelos Kiskinis
- Department of Stem Cell and Regenerative Biology, Harvard
University, Cambridge, MA 02138
| | - Brett Winborn
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Brian D. Freibaum
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Anderson Kanagaraj
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Alison J. Clare
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Nisha M. Badders
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Bilada Bilican
- Euan MacDonald Centre for Motor Neurone Disease Research,
Medical Research Council Centre for Regenerative Medicine, Centre for
Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Edward Chaum
- Department of Ophthalmology, University of Tennessee Health
Sciences Center, Memphis, TN 38163, USA
| | - Siddharthan Chandran
- Euan MacDonald Centre for Motor Neurone Disease Research,
Medical Research Council Centre for Regenerative Medicine, Centre for
Neuroregeneration, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Christopher E. Shaw
- Departments of Clinical Neuroscience and Neurodegeneration
and Brain Injury, King's College London and King's Health Partners, MRC Centre for
Neurodegeneration Research, London SE5 8AF, UK
| | - Kevin C. Eggan
- Department of Stem Cell and Regenerative Biology, Harvard
University, Cambridge, MA 02138
| | - Tom Maniatis
- Department of Biochemistry and Molecular Biophysics,
Columbia University Medical Center, New York, NY 10032, USA
| | - J. Paul Taylor
- Department of Developmental Neurobiology, St. Jude
Children's Research Hospital, Memphis, Tennessee 38105, USA
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13
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Zhang X, Zajac AL, Huang L, Behlke MA, Tsourkas A. Imaging the directed transport of single engineered RNA transcripts in real-time using ratiometric bimolecular beacons. PLoS One 2014; 9:e85813. [PMID: 24454933 PMCID: PMC3893274 DOI: 10.1371/journal.pone.0085813] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 12/02/2013] [Indexed: 11/26/2022] Open
Abstract
The relationship between RNA expression and cell function can often be difficult to decipher due to the presence of both temporal and sub-cellular processing of RNA. These intricacies of RNA regulation can often be overlooked when only acquiring global measurements of RNA expression. This has led to development of several tools that allow for the real-time imaging of individual engineered RNA transcripts in living cells. Here, we describe a new technique that utilizes an oligonucleotide-based probe, ratiometric bimolecular beacon (RBMB), to image RNA transcripts that were engineered to contain 96-tandem repeats of the RBMB target sequence in the 3′-untranslated region. Binding of RBMBs to the target RNA resulted in discrete bright fluorescent spots, representing individual transcripts, that could be imaged in real-time. Since RBMBs are a synthetic probe, the use of photostable, bright, and red-shifted fluorophores led to a high signal-to-background. RNA motion was readily characterized by both mean squared displacement and moment scaling spectrum analyses. These analyses revealed clear examples of directed, Brownian, and subdiffusive movements.
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Affiliation(s)
- Xuemei Zhang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Allison L. Zajac
- Cell Biology and Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Lingyan Huang
- Integrated DNA Technologies, Inc., Coralville, Iowa, United States of America
| | - Mark A. Behlke
- Integrated DNA Technologies, Inc., Coralville, Iowa, United States of America
| | - Andrew Tsourkas
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Boutorine AS, Novopashina DS, Krasheninina OA, Nozeret K, Venyaminova AG. Fluorescent probes for nucleic Acid visualization in fixed and live cells. Molecules 2013; 18:15357-97. [PMID: 24335616 PMCID: PMC6270009 DOI: 10.3390/molecules181215357] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 11/20/2013] [Accepted: 12/05/2013] [Indexed: 12/13/2022] Open
Abstract
This review analyses the literature concerning non-fluorescent and fluorescent probes for nucleic acid imaging in fixed and living cells from the point of view of their suitability for imaging intracellular native RNA and DNA. Attention is mainly paid to fluorescent probes for fluorescence microscopy imaging. Requirements for the target-binding part and the fluorophore making up the probe are formulated. In the case of native double-stranded DNA, structure-specific and sequence-specific probes are discussed. Among the latest, three classes of dsDNA-targeting molecules are described: (i) sequence-specific peptides and proteins; (ii) triplex-forming oligonucleotides and (iii) polyamide oligo(N-methylpyrrole/N-methylimidazole) minor groove binders. Polyamides seem to be the most promising targeting agents for fluorescent probe design, however, some technical problems remain to be solved, such as the relatively low sequence specificity and the high background fluorescence inside the cells. Several examples of fluorescent probe applications for DNA imaging in fixed and living cells are cited. In the case of intracellular RNA, only modified oligonucleotides can provide such sequence-specific imaging. Several approaches for designing fluorescent probes are considered: linear fluorescent probes based on modified oligonucleotide analogs, molecular beacons, binary fluorescent probes and template-directed reactions with fluorescence probe formation, FRET donor-acceptor pairs, pyrene excimers, aptamers and others. The suitability of all these methods for living cell applications is discussed.
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Affiliation(s)
- Alexandre S. Boutorine
- Muséum National d’Histoire Naturelle, CNRS, UMR 7196, INSERM, U565, 57 rue Cuvier, B.P. 26, Paris Cedex 05, F-75231, France; E-Mail:
| | - Darya S. Novopashina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentyev Ave., 8, Novosibirsk 630090, Russia; E-Mails: (D.S.N.); (O.A.K.); (A.G.V.)
| | - Olga A. Krasheninina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentyev Ave., 8, Novosibirsk 630090, Russia; E-Mails: (D.S.N.); (O.A.K.); (A.G.V.)
- Department of Natural Sciences, Novosibirsk State University, Pirogova Str., 2, Novosibirsk 630090, Russia
| | - Karine Nozeret
- Muséum National d’Histoire Naturelle, CNRS, UMR 7196, INSERM, U565, 57 rue Cuvier, B.P. 26, Paris Cedex 05, F-75231, France; E-Mail:
| | - Alya G. Venyaminova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Lavrentyev Ave., 8, Novosibirsk 630090, Russia; E-Mails: (D.S.N.); (O.A.K.); (A.G.V.)
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15
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Dahan L, Huang L, Kedmi R, Behlke MA, Peer D. SNP detection in mRNA in living cells using allele specific FRET probes. PLoS One 2013; 8:e72389. [PMID: 24039756 PMCID: PMC3767744 DOI: 10.1371/journal.pone.0072389] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 07/09/2013] [Indexed: 12/24/2022] Open
Abstract
Live mRNA detection allows real time monitoring of specific transcripts and genetic alterations. The main challenge of live genetic detection is overcoming the high background generated by unbound probes and reaching high level of specificity with minimal off target effects. The use of Fluorescence Resonance Energy Transfer (FRET) probes allows differentiation between bound and unbound probes thus decreasing background. Probe specificity can be optimized by adjusting the length and through use of chemical modifications that alter binding affinity. Herein, we report the use of two oligonucleotide FRET probe system to detect a single nucleotide polymorphism (SNP) in murine Hras mRNA, which is associated with malignant transformations. The FRET oligonucleotides were modified with phosphorothioate (PS) bonds, 2′OMe RNA and LNA residues to enhance nuclease stability and improve SNP discrimination. Our results show that a point mutation in Hras can be detected in endogenous RNA of living cells. As determined by an Acceptor Photobleaching method, FRET levels were higher in cells transfected with perfect match FRET probes whereas a single mismatch showed decreased FRET signal. This approach promotes in vivo molecular imaging methods and could further be applied in cancer diagnosis and theranostic strategies.
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Affiliation(s)
- Liya Dahan
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
- Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Lingyan Huang
- Integrated DNA Technologies, Coralville, Iowa, United States of America
| | - Ranit Kedmi
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
- Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Mark A. Behlke
- Integrated DNA Technologies, Coralville, Iowa, United States of America
- * E-mail: (MAB); (DP)
| | - Dan Peer
- Department of Cell Research and Immunology, Tel Aviv University, Tel Aviv, Israel
- Center for Nanoscience and Nanotechnology, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (MAB); (DP)
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16
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Zhang X, Song Y, Shah AY, Lekova V, Raj A, Huang L, Behlke MA, Tsourkas A. Quantitative assessment of ratiometric bimolecular beacons as a tool for imaging single engineered RNA transcripts and measuring gene expression in living cells. Nucleic Acids Res 2013; 41:e152. [PMID: 23814183 PMCID: PMC3753654 DOI: 10.1093/nar/gkt561] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Recently, we developed an oligonucleotide-based probe, ratiometric bimolecular beacon (RBMB), which generates a detectable fluorescent signal in living cells that express the target RNA. Here, we show that RBMBs can also be used to image single RNA transcripts in living cells, when the target RNA is engineered to contain as few as four hybridization sites. Moreover, comparison with single-molecule fluorescence in situ hybridization confirmed that RBMBs could be used to accurately quantify the number of RNA transcripts within individual cells. Measurements of gene expression could be acquired within 30 min and using a wide range of RBMB concentrations. The ability to acquire accurate measurements of RNA copy number in both HT-1080 cells and CHO cells also suggests that RBMBs can be used to image and quantify single RNA transcripts in a wide range of cell lines. Overall, these findings highlight the robustness and versatility of RBMBs as a tool for imaging RNA in live cells. We envision that the unique capabilities of RBMBs will open up new avenues for RNA research.
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Affiliation(s)
- Xuemei Zhang
- Department of Bioengineering, University of Pennsylvania, 210 S. 33rd Street, 240 Skirkanich Hall, Philadelphia, PA 19104, USA, Department of Biology, University of Pennsylvania, 433 S. University Ave, 102 Leidy Laboratories, Philadelphia, PA 19104, USA and Integrated DNA Technologies, Inc., 1710 Commercial Park, Coralville, IA 52241, USA
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17
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Yan Y, Yan J, Piao X, Zhang T, Guan Y. Effect of LNA- and OMeN-modified oligonucleotide probes on the stability and discrimination of mismatched base pairs of duplexes. J Biosci 2012; 37:233-41. [PMID: 22581329 DOI: 10.1007/s12038-012-9196-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Locked nucleic acid (LNA) and 2'-O-methyl nucleotide (OMeN) are the most extensively studied nucleotide analogues. Although both LNA and OMeN are characterized by the C3'-endo sugar pucker conformation, which is dominant in A-form DNA and RNA nucleotides, they demonstrate different binding behaviours. Previous studies have focused attention on their properties of duplex stabilities, hybridization kinetics and resistance against nuclease digestion; however, their ability to discriminate mismatched hybridizations has been explored much less. In this study, LNA- and OMeN-modified oligonucleotide probes have been prepared and their effects on the DNA duplex stability have been examined: LNA modifications can enhance the duplex stability, whereas OMeN modifications reduce the duplex stability. Next, we studied how the LNA:DNA and OMeN:DNA mismatches reduced the duplex stability. Melting temperature measurement showed that different LNA:DNA or OMeN:DNA mismatches indeed influence the duplex stability differently. LNA purines can discriminate LNA:DNA mismatches more effectively than LNA pyrimidines as well as DNA nucleotides. Furthermore, we designed five LNA- and five OMeN-modified oligonucleotide probes to simulate realistic situations where target-probe duplexes contain a complementary LNA:DNA or OMeN:DNA base pairs and a DNA:DNA mismatch simultaneously. The measured collective effect showed that the duplex stability was enhanced by the complementary LNA:DNA base pair but decreased by the DNA:DNA mismatch in a position-dependent manner regardless of the chemical identity and position of the complementary LNA:DNA base pair. On the other hand, the OMeN-modified probes also showed that the duplex stability was reduced by both the OMeN modification and the OMeN:DNA mismatch in a position-dependent manner.
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Affiliation(s)
- Ying Yan
- Department of Biochemistry and Molecular Biology, Key Laboratory of Medical Cell Biology of Minister of Education, China Medical University, Shenyang, Liaoning, 110001, China
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18
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Su X, Xiao X, Zhang C, Zhao M. Nucleic acid fluorescent probes for biological sensing. APPLIED SPECTROSCOPY 2012; 66:1249-1262. [PMID: 23146180 DOI: 10.1366/12-06803] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Nucleic acid fluorescent probes are playing increasingly important roles in biological sensing in recent years. In addition to the conventional functions of single-stranded DNA/RNA to hybridize with their complementary strands, affinity nucleic acids (aptamers) with specific target binding properties have also been developed, which has greatly broadened the application of nucleic acid fluorescent probes to the detection of a large variety of analytes, including small molecules, proteins, ions, and even whole cells. Another chemical property of nucleic acids is to act as substrates for various nucleic acid enzymes. This property can be utilized not only to detect those enzymes and screen their inhibitors, but also employed to develop effective signal amplification systems, which implies extensive applications. This review mainly covers the biosensing methods based on the above three types of nucleic acid fluorescent probes. The most widely used intensity-based biosensing assays are covered first, including nucleic acid probe-based signal amplification methods. Then fluorescence lifetime, fluorescence anisotropy, and fluorescence correlation spectroscopy assays are introduced, respectively. As a rapidly developing field, fluorescence imaging approaches are also briefly summarized.
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Affiliation(s)
- Xin Su
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, China
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19
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Kam Y, Rubinstein A, Nissan A, Halle D, Yavin E. Detection of endogenous K-ras mRNA in living cells at a single base resolution by a PNA molecular beacon. Mol Pharm 2012; 9:685-93. [PMID: 22289057 DOI: 10.1021/mp200505k] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Detection of mRNA alterations is a promising approach for identifying biomarkers as means of differentiating benign from malignant lesions. By choosing the KRAS oncogene as a target gene, two types of molecular beacons (MBs) based on either phosphothioated DNA (PS-DNA-MB) or peptide nucleic acid (TO-PNA-MB, where TO = thiazole orange) were synthesized and compared in vitro and in vivo. Their specificity was examined in wild-type KRAS (HT29) or codon 12 point mutation (Panc-1, SW480) cells. Incubation of both beacons with total RNA extracted from the Panc-1 cell line (fully complementary sequence) showed a fluorescent signal for both beacons. Major differences were observed, however, for single mismatch mRNA transcripts in cell lines HT29 and SW480. PS-DNA-MB weakly discriminated such single mismatches in comparison to TO-PNA-MB, which was profoundly more sensitive. Cell transfection of TO-PNA-MB with the aid of PEI resulted in fluorescence in cells expressing the fully complementary RNA transcript (Panc-1) but undetectable fluorescence in cells expressing the K-ras mRNA that has a single mismatch to the designed TO-PNA-MB (HT29). A weaker fluorescent signal was also detected in SW480 cells; however, these cells express approximately one-fifth of the target mRNA of the designed TO-PNA-MB. In contrast, PS-DNA-MB showed no fluorescence in all cell lines tested post PEI transfection. Based on the fast hybridization kinetics and on the single mismatch discrimination found for TO-PNA-MB we believe that such molecular beacons are promising for in vivo real-time imaging of endogenous mRNA with single nucleotide polymorphism (SNP) resolution.
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Affiliation(s)
- Yossi Kam
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, PO Box 12065, Jerusalem 91120, Israel
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20
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A transformer of molecular beacon for sensitive and real-time detection of phosphatases with effective inhibition of the false positive signals. Biosens Bioelectron 2011; 28:13-6. [DOI: 10.1016/j.bios.2011.06.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Revised: 05/25/2011] [Accepted: 06/01/2011] [Indexed: 12/12/2022]
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21
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Monroy-Contreras R, Vaca L. Molecular beacons: powerful tools for imaging RNA in living cells. J Nucleic Acids 2011; 2011:741723. [PMID: 21876785 PMCID: PMC3163130 DOI: 10.4061/2011/741723] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 06/14/2011] [Accepted: 06/22/2011] [Indexed: 12/25/2022] Open
Abstract
Recent advances in RNA functional studies highlights the pivotal role of these molecules in cell physiology. Diverse methods have been implemented to measure the expression levels of various RNA species, using either purified RNA or fixed cells. Despite the fact that fixed cells offer the possibility to observe the spatial distribution of RNA, assays with capability to real-time monitoring RNA transport into living cells are needed to further understand the role of RNA dynamics in cellular functions. Molecular beacons (MBs) are stem-loop hairpin-structured oligonucleotides equipped with a fluorescence quencher at one end and a fluorescent dye (also called reporter or fluorophore) at the opposite end. This structure permits that MB in the absence of their target complementary sequence do not fluoresce. Upon binding to targets, MBs emit fluorescence, due to the spatial separation of the quencher and the reporter. Molecular beacons are promising probes for the development of RNA imaging techniques; nevertheless much work remains to be done in order to obtain a robust technology for imaging various RNA molecules together in real time and in living cells. The present work concentrates on the different requirements needed to use successfully MB for cellular studies, summarizing recent advances in this area.
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Affiliation(s)
- Ricardo Monroy-Contreras
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 Mexico, DF, Mexico
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22
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Sivaraman D, Biswas P, Cella LN, Yates MV, Chen W. Detecting RNA viruses in living mammalian cells by fluorescence microscopy. Trends Biotechnol 2011; 29:307-13. [PMID: 21529975 DOI: 10.1016/j.tibtech.2011.02.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 02/20/2011] [Accepted: 02/23/2011] [Indexed: 12/29/2022]
Abstract
Traditional methods that rely on viral isolation and culture techniques continue to be the gold standards used for detection of infectious viral particles. However, new techniques that rely on visualization of live cells can shed light on understanding virus-host interaction for early stage detection and potential drug discovery. Live-cell imaging techniques that incorporate fluorescent probes into viral components provide opportunities for understanding mRNA expression, interaction, and virus movement and localization. Other viral replication events inside a host cell can be exploited for non-invasive detection, such as single-virus tracking, which does not inhibit viral infectivity or cellular function. This review highlights some of the recent advances made using these novel approaches for visualization of viral entry and replication in live cells.
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Affiliation(s)
- Divya Sivaraman
- Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA
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23
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Su X, Zhang C, Zhao M. Discrimination of the false-positive signals of molecular beacons by combination of heat inactivation and using single walled carbon nanotubes. Biosens Bioelectron 2011; 26:3596-601. [DOI: 10.1016/j.bios.2011.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 01/22/2011] [Accepted: 02/09/2011] [Indexed: 01/03/2023]
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24
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Chen AK, Rhee WJ, Bao G, Tsourkas A. Delivery of molecular beacons for live-cell imaging and analysis of RNA. Methods Mol Biol 2011; 714:159-74. [PMID: 21431740 DOI: 10.1007/978-1-61779-005-8_10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over the past decade, a variety of oligonucleotide-based probes have been developed that allow for direct visualization of RNA molecules in living cells. Of these, molecular beacons have garnered a particularly high degree of interest due to their simple yet exquisite unimolecular stem-loop design that allows for the efficient conversion of target recognition into a specific fluorescent signal. As a result of their favorable fluorescent enhancement and their high specificity, molecular beacons have been used for a wide range of applications, including the monitoring of RNA expression and localization in living cells, cancer cell detection, and the study of viral infections. In this chapter we describe a general methodology that can be followed for the imaging and analysis of RNA in living cells using molecular beacons. Several commonly employed methods for delivering molecular beacons into the cytosol are discussed including toxin-based cell membrane permeabilization, microinjection, and microporation. Strategies for acquiring ratiometric measurements are also described.
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Affiliation(s)
- Antony K Chen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
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25
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Forsha SJ, Panyutin IV, Neumann RD, Panyutin IG. Intracellular traffic of oligodeoxynucleotides in and out of the nucleus: effect of exportins and DNA structure. Oligonucleotides 2010; 20:277-84. [PMID: 20946012 DOI: 10.1089/oli.2010.0255] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The delivery of oligodeoxynucleotides (ODNs) into cells is widely utilized for antisense, antigene, aptamer, and similar approaches to regulate gene and protein activities based upon the ODNs' sequence-specific recognition. Short pieces of DNA can also be generated in biological processes, for example, after degradation of viral or bacterial DNA. However, the mechanisms that regulate intracellular trafficking and localization of ODNs are not fully understood. Here we study the effects of major transporters of microRNA, exportin-1 (Exp1) and exportin-5 (Exp5), on the transport of single-stranded ODNs in and out of the nucleus. For this, we employed a fluorescent microscopy-based assay to quantitatively measure the redistribution of ODNs between the nucleus and cytoplasm of live cells. By measuring the fluorescent signal of the nuclei we observed that after delivery into cells via cationic liposomes ODNs rapidly accumulated inside nuclei. However, after removal of the ODN/liposome containing media, we found re-localization of ODNs from the nuclei to cytoplasm of the cells over the time course of several hours. Downregulation of the Exp5 gene by siRNA resulted in a slight increase of ODN uptake into the nucleus, but the kinetics of ODN efflux to the cytoplasm was not affected. Inhibition of Exp1 with leptomycin B somewhat slowed down the clearance of ODNs from the nucleus; however, within 6 hours most of the ODN were still being cleared form the nucleus. ODNs that could form intramolecular G-quadruplex structures behaved differently. They also accumulated in nuclei, although at a lesser extent than unstructured ODN, but they remained there for up to 20 hours after transfection, causing significant cell death. We conclude that Exp1 and Exp5 are not the major transporters of our ODNs out of the nucleus, and that the transport of ODNs is strongly affected by their secondary structure.
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Affiliation(s)
- Stephen J Forsha
- Radiology and Imaging Sciences Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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26
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Chen AK, Davydenko O, Behlke MA, Tsourkas A. Ratiometric bimolecular beacons for the sensitive detection of RNA in single living cells. Nucleic Acids Res 2010; 38:e148. [PMID: 20507905 PMCID: PMC2919734 DOI: 10.1093/nar/gkq436] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Numerous studies have utilized molecular beacons (MBs) to image RNA expression in living cells; however, there is growing evidence that the sensitivity of RNA detection is significantly hampered by their propensity to emit false-positive signals. To overcome these limitations, we have developed a new RNA imaging probe called ratiometric bimolecular beacon (RBMB), which combines functional elements of both conventional MBs and siRNA. Analogous to MBs, RBMBs elicit a fluorescent reporter signal upon hybridization to complementary RNA. In addition, an siRNA-like double-stranded domain is used to facilitate nuclear export. Accordingly, live-cell fluorescent imaging showed that RBMBs are localized predominantly in the cytoplasm, whereas MBs are sequestered into the nucleus. The retention of RBMBs within the cytoplasmic compartment led to >15-fold reduction in false-positive signals and a significantly higher signal-to-background compared with MBs. The RBMBs were also designed to possess an optically distinct reference fluorophore that remains unquenched regardless of probe confirmation. This reference dye not only provided a means to track RBMB localization, but also allowed single cell measurements of RBMB fluorescence to be corrected for variations in probe delivery. Combined, these attributes enabled RBMBs to exhibit an improved sensitivity for RNA detection in living cells.
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Affiliation(s)
- Antony K Chen
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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