1
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Rosspopoff O, Cazottes E, Huret C, Loda A, Collier A, Casanova M, Rugg-Gunn P, Heard E, Ouimette JF, Rougeulle C. Species-specific regulation of XIST by the JPX/FTX orthologs. Nucleic Acids Res 2023; 51:2177-2194. [PMID: 36727460 PMCID: PMC10018341 DOI: 10.1093/nar/gkad029] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 12/08/2022] [Accepted: 01/11/2023] [Indexed: 02/03/2023] Open
Abstract
X chromosome inactivation (XCI) is an essential process, yet it initiates with remarkable diversity in various mammalian species. XIST, the main trigger of XCI, is controlled in the mouse by an interplay of lncRNA genes (LRGs), some of which evolved concomitantly to XIST and have orthologues across all placental mammals. Here, we addressed the functional conservation of human orthologues of two such LRGs, FTX and JPX. By combining analysis of single-cell RNA-seq data from early human embryogenesis with various functional assays in matched human and mouse pluripotent stem- or differentiated post-XCI cells, we demonstrate major functional differences for these orthologues between species, independently of primary sequence conservation. While the function of FTX is not conserved in humans, JPX stands as a major regulator of XIST expression in both species. However, we show that different entities of JPX control the production of XIST at various steps depending on the species. Altogether, our study highlights the functional versatility of LRGs across evolution, and reveals that functional conservation of orthologous LRGs may involve diversified mechanisms of action. These findings represent a striking example of how the evolvability of LRGs can provide adaptative flexibility to constrained gene regulatory networks.
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Affiliation(s)
- Olga Rosspopoff
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France
| | - Emmanuel Cazottes
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France
| | - Christophe Huret
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France
| | - Agnese Loda
- Directors' research, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Amanda J Collier
- Epigenetics Programme, The Babraham Institute, Cambridge CB22 3AT, UK
- Wellcome Trust – Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, UK
| | - Miguel Casanova
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France
| | - Peter J Rugg-Gunn
- Epigenetics Programme, The Babraham Institute, Cambridge CB22 3AT, UK
- Wellcome Trust – Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, UK
| | - Edith Heard
- Directors' research, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Collège de France, Paris, France
| | | | - Claire Rougeulle
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France
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2
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Pekarek L, Zimmer MM, Gribling-Burrer AS, Buck S, Smyth R, Caliskan N. Cis-mediated interactions of the SARS-CoV-2 frameshift RNA alter its conformations and affect function. Nucleic Acids Res 2022; 51:728-743. [PMID: 36537211 PMCID: PMC9881162 DOI: 10.1093/nar/gkac1184] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 11/11/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
The RNA genome of SARS-CoV-2 contains a frameshift stimulatory element (FSE) that allows access to an alternative reading frame through -1 programmed ribosomal frameshifting (PRF). -1PRF in the 1a/1b gene is essential for efficient viral replication and transcription of the viral genome. -1PRF efficiency relies on the presence of conserved RNA elements within the FSE. One of these elements is a three-stemmed pseudoknot, although alternative folds of the frameshift site might have functional roles as well. Here, by complementing ensemble and single-molecule structural analysis of SARS-CoV-2 frameshift RNA variants with functional data, we reveal a conformational interplay of the 5' and 3' immediate regions with the FSE and show that the extended FSE exists in multiple conformations. Furthermore, limiting the base pairing of the FSE with neighboring nucleotides can favor or impair the formation of the alternative folds, including the pseudoknot. Our results demonstrate that co-existing RNA structures can function together to fine-tune SARS-CoV-2 gene expression, which will aid efforts to design specific inhibitors of viral frameshifting.
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Affiliation(s)
- Lukas Pekarek
- Helmholtz Institute for RNA-based Infection Research (HIRI-HZI), Würzburg, Germany
| | | | | | | | - Redmond Smyth
- Correspondence may also be addressed to Redmond Smyth.
| | - Neva Caliskan
- To whom correspondence should be addressed. Tel: +49 931 318 5298;
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3
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Ivanov GS, Tribulovich VG, Pestov NB, David TI, Amoah AS, Korneenko TV, Barlev NA. Artificial genetic polymers against human pathologies. Biol Direct 2022; 17:39. [PMID: 36474260 PMCID: PMC9727881 DOI: 10.1186/s13062-022-00353-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
Originally discovered by Nielsen in 1991, peptide nucleic acids and other artificial genetic polymers have gained a lot of interest from the scientific community. Due to their unique biophysical features these artificial hybrid polymers are now being employed in various areas of theranostics (therapy and diagnostics). The current review provides an overview of their structure, principles of rational design, and biophysical features as well as highlights the areas of their successful implementation in biology and biomedicine. Finally, the review discusses the areas of improvement that would allow their use as a new class of therapeutics in the future.
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Affiliation(s)
- Gleb S Ivanov
- Institute of Cytology, Tikhoretsky Ave 4, Saint Petersburg, Russia, 194064
- St. Petersburg State Technological Institute (Technical University), Saint Petersburg, Russia, 190013
| | - Vyacheslav G Tribulovich
- St. Petersburg State Technological Institute (Technical University), Saint Petersburg, Russia, 190013
| | - Nikolay B Pestov
- Chumakov Federal Scientific Center for Research and Development of Immune-and-Biological Products, Moscow, Russia, 108819
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia, 141701
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, 117997
- Institute of Biomedical Chemistry, Moscow, Russia, 119121б
| | - Temitope I David
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia, 141701
| | - Abdul-Saleem Amoah
- Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia, 141701
| | - Tatyana V Korneenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow, Russia, 117997
| | - Nikolai A Barlev
- Institute of Cytology, Tikhoretsky Ave 4, Saint Petersburg, Russia, 194064.
- Institute of Biomedical Chemistry, Moscow, Russia, 119121б.
- School of Medicine, Nazarbayev University, 010000, Astana, Kazakhstan.
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4
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Bailey JK, Shen W, Liang XH, Crooke ST. Nucleic acid binding proteins affect the subcellular distribution of phosphorothioate antisense oligonucleotides. Nucleic Acids Res 2017; 45:10649-10671. [PMID: 28977508 PMCID: PMC5737868 DOI: 10.1093/nar/gkx709] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/04/2017] [Indexed: 12/15/2022] Open
Abstract
Antisense oligonucleotides (ASOs) are versatile tools that can regulate multiple steps of RNA biogenesis in cells and living organisms. Significant improvements in delivery, potency, and stability have been achieved through modifications within the oligonucleotide backbone, sugar and heterocycles. However, these modifications can profoundly affect interactions between ASOs and intracellular proteins in ways that are only beginning to be understood. Here, we report that ASOs with specific backbone and sugar modifications can become localized to cytoplasmic ribonucleoprotein granules such as stress granules and those seeded by the aggregation of specific ASO-binding proteins such as FUS/TLS (FUS) and PSF/SFPQ (PSF). Further investigation into the basis for ASO-FUS binding illustrated the importance of ASO backbone and hydrophobic 2' sugar modifications and revealed that the C-terminal region of FUS is sufficient to retain ASOs in cellular foci. Taken together, the results of this study demonstrate that affinities of various nucleic acid binding domains for ASO depend on chemical modifications and further demonstrate how ASO-protein interactions influence the localization of ASOs.
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Affiliation(s)
- Jeffrey K Bailey
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Wen Shen
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Xue-Hai Liang
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
| | - Stanley T Crooke
- Department of Core Antisense Research, Ionis Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA
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5
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Zaghloul EM, Gissberg O, Moreno PMD, Siggens L, Hällbrink M, Jørgensen AS, Ekwall K, Zain R, Wengel J, Lundin KE, Smith CIE. CTG repeat-targeting oligonucleotides for down-regulating Huntingtin expression. Nucleic Acids Res 2017; 45:5153-5169. [PMID: 28334749 PMCID: PMC5435994 DOI: 10.1093/nar/gkx111] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/06/2017] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease (HD) is a fatal, neurodegenerative disorder in which patients suffer from mobility, psychological and cognitive impairments. Existing therapeutics are only symptomatic and do not significantly alter the disease progression or increase life expectancy. HD is caused by expansion of the CAG trinucleotide repeat region in exon 1 of the Huntingtin gene (HTT), leading to the formation of mutant HTT transcripts (muHTT). The toxic gain-of-function of muHTT protein is a major cause of the disease. In addition, it has been suggested that the muHTT transcript contributes to the toxicity. Thus, reduction of both muHTT mRNA and protein levels would ideally be the most useful therapeutic option. We herein present a novel strategy for HD treatment using oligonucleotides (ONs) directly targeting the HTT trinucleotide repeat DNA. A partial, but significant and potentially long-term, HTT knock-down of both mRNA and protein was successfully achieved. Diminished phosphorylation of HTT gene-associated RNA-polymerase II is demonstrated, suggestive of reduced transcription downstream the ON-targeted repeat. Different backbone chemistries were found to have a strong impact on the ON efficiency. We also successfully use different delivery vehicles as well as naked uptake of the ONs, demonstrating versatility and possibly providing insights for in vivo applications.
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Affiliation(s)
- Eman M Zaghloul
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86 Huddinge, Stockholm, Sweden.,Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, El-Khartoum square, Azareeta, 21 521 Alexandria, Egypt
| | - Olof Gissberg
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86 Huddinge, Stockholm, Sweden
| | - Pedro M D Moreno
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86 Huddinge, Stockholm, Sweden.,Instituto de Engenharia Biomédica, Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135, Porto, Portugal
| | - Lee Siggens
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden, SE-141 86, Huddinge, Stockholm, Sweden
| | - Mattias Hällbrink
- Department of Neurochemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Anna S Jørgensen
- Department of Physics and Chemistry, Nucleic Acid Centre University of Southern Denmark, DK-5230 Odense, Denmark
| | - Karl Ekwall
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden, SE-141 86, Huddinge, Stockholm, Sweden
| | - Rula Zain
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86 Huddinge, Stockholm, Sweden.,Department of Clinical Genetics, Centre for Rare Diseases, Karolinska University Hospital, SE-171 76 Stockholm, Sweden
| | - Jesper Wengel
- Department of Physics and Chemistry, Nucleic Acid Centre University of Southern Denmark, DK-5230 Odense, Denmark
| | - Karin E Lundin
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86 Huddinge, Stockholm, Sweden
| | - C I Edvard Smith
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, SE-141 86 Huddinge, Stockholm, Sweden
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6
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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7
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Controlling gene networks and cell fate with precision-targeted DNA-binding proteins and small-molecule-based genome readers. Biochem J 2014; 462:397-413. [PMID: 25145439 DOI: 10.1042/bj20140400] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Transcription factors control the fate of a cell by regulating the expression of genes and regulatory networks. Recent successes in inducing pluripotency in terminally differentiated cells as well as directing differentiation with natural transcription factors has lent credence to the efforts that aim to direct cell fate with rationally designed transcription factors. Because DNA-binding factors are modular in design, they can be engineered to target specific genomic sequences and perform pre-programmed regulatory functions upon binding. Such precision-tailored factors can serve as molecular tools to reprogramme or differentiate cells in a targeted manner. Using different types of engineered DNA binders, both regulatory transcriptional controls of gene networks, as well as permanent alteration of genomic content, can be implemented to study cell fate decisions. In the present review, we describe the current state of the art in artificial transcription factor design and the exciting prospect of employing artificial DNA-binding factors to manipulate the transcriptional networks as well as epigenetic landscapes that govern cell fate.
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8
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Russo Krauss I, Parkinson GN, Merlino A, Mattia CA, Randazzo A, Novellino E, Mazzarella L, Sica F. A regular thymine tetrad and a peculiar supramolecular assembly in the first crystal structure of an all-LNA G-quadruplex. ACTA ACUST UNITED AC 2014; 70:362-70. [PMID: 24531470 DOI: 10.1107/s1399004713028095] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/13/2013] [Indexed: 01/19/2023]
Abstract
Locked nucleic acids (LNAs) are formed by bicyclic ribonucleotides where the O2' and C4' atoms are linked through a methylene bridge and the sugar is blocked in a 3'-endo conformation. They represent a promising tool for therapeutic and diagnostic applications and are characterized by higher thermal stability and nuclease resistance with respect to their natural counterparts. However, structural descriptions of LNA-containing quadruplexes are rather limited, since few NMR models have been reported in the literature. Here, the first crystallographically derived model of an all-LNA-substituted quadruplex-forming sequence 5'-TGGGT-3' is presented refined at 1.7 Å resolution. This high-resolution crystallographic analysis reveals a regular parallel G-quadruplex arrangement terminating in a well defined thymine tetrad at the 3'-end. The detailed picture of the hydration pattern reveals LNA-specific features in the solvent distribution. Interestingly, two closely packed quadruplexes are present in the asymmetric unit. They face one another with their 3'-ends giving rise to a compact higher-order structure. This new assembly suggests a possible way in which sequential quadruplexes can be disposed in the crowded cell environment. Furthermore, as the formation of ordered structures by molecular self-assembly is an effective strategy to obtain nanostructures, this study could open the way to the design of a new class of LNA-based building blocks for nanotechnology.
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Affiliation(s)
- Irene Russo Krauss
- Department of Chemical Sciences, University of Naples `Federico II', Complesso Universitario di Monte Sant'Angelo, Via Cinthia, I-80126 Napoli, Italy
| | - Gary Nigel Parkinson
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, England
| | - Antonello Merlino
- Department of Chemical Sciences, University of Naples `Federico II', Complesso Universitario di Monte Sant'Angelo, Via Cinthia, I-80126 Napoli, Italy
| | - Carlo Andrea Mattia
- Department of Pharmacy, University of Salerno, Via Ponte Don Melillo, I-84084 Fisciano, Italy
| | - Antonio Randazzo
- Department of Pharmacy, University of Naples `Federico II', Via D. Montesano 49, I-80131 Napoli, Italy
| | - Ettore Novellino
- Department of Pharmacy, University of Naples `Federico II', Via D. Montesano 49, I-80131 Napoli, Italy
| | - Lelio Mazzarella
- Department of Chemical Sciences, University of Naples `Federico II', Complesso Universitario di Monte Sant'Angelo, Via Cinthia, I-80126 Napoli, Italy
| | - Filomena Sica
- Department of Chemical Sciences, University of Naples `Federico II', Complesso Universitario di Monte Sant'Angelo, Via Cinthia, I-80126 Napoli, Italy
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9
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Moreno PMD, Geny S, Pabon YV, Bergquist H, Zaghloul EM, Rocha CSJ, Oprea II, Bestas B, Andaloussi SE, Jørgensen PT, Pedersen EB, Lundin KE, Zain R, Wengel J, Smith CIE. Development of bis-locked nucleic acid (bisLNA) oligonucleotides for efficient invasion of supercoiled duplex DNA. Nucleic Acids Res 2013; 41:3257-73. [PMID: 23345620 PMCID: PMC3597675 DOI: 10.1093/nar/gkt007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In spite of the many developments in synthetic oligonucleotide (ON) chemistry and design, invasion into double-stranded DNA (DSI) under physiological salt and pH conditions remains a challenge. In this work, we provide a new ON tool based on locked nucleic acids (LNAs), designed for strand invasion into duplex DNA (DSI). We thus report on the development of a clamp type of LNA ON—bisLNA—with capacity to bind and invade into supercoiled double-stranded DNA. The bisLNA links a triplex-forming, Hoogsteen-binding, targeting arm with a strand-invading Watson–Crick binding arm. Optimization was carried out by varying the number and location of LNA nucleotides and the length of the triplex-forming versus strand-invading arms. Single-strand regions in target duplex DNA were mapped using chemical probing. By combining design and increase in LNA content, it was possible to achieve a 100-fold increase in potency with 30% DSI at 450 nM using a bisLNA to plasmid ratio of only 21:1. Although this first conceptual report does not address the utility of bisLNA for the targeting of DNA in a chromosomal context, it shows bisLNA as a promising candidate for interfering also with cellular genes.
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Affiliation(s)
- Pedro M D Moreno
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, 141 86 Huddinge, Stockholm, Sweden
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10
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Lundin KE, Højland T, Hansen BR, Persson R, Bramsen JB, Kjems J, Koch T, Wengel J, Smith CIE. Biological activity and biotechnological aspects of locked nucleic acids. ADVANCES IN GENETICS 2013; 82:47-107. [PMID: 23721720 DOI: 10.1016/b978-0-12-407676-1.00002-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Locked nucleic acid (LNA) is one of the most promising new nucleic acid analogues that has been produced under the past two decades. In this chapter, we have tried to cover many of the different areas, where this molecule has been used to improve the function of synthetic oligonucleotides (ONs). The use of LNA in antisense ONs, including gapmers, splice-switching ONs, and siLNA, as well as antigene ONs, is reviewed. Pharmacokinetics as well as pharmacodynamics of LNA ONs and a description of selected compounds in, or close to, clinical testing are described. In addition, new LNA modifications and the adaptation of enzymes for LNA incorporation are reviewed. Such enzymes may become important for the development of stabilized LNA-containing aptamers.
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Affiliation(s)
- Karin E Lundin
- Clinical Research Center, Department of Laboratory Medicine, Karolinska Institutet, Novum, Huddinge, Stockholm, Sweden.
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11
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Knowling S, Stapleton K, Turner AMW, Uhlmann E, Lehmann T, Vollmer J, Morris KV. Chemically Modified Oligonucleotides Modulate an Epigenetically Varied and Transient Form of Transcription Silencing of HIV-1 in Human Cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2012; 1:e16. [PMID: 23343927 PMCID: PMC3381641 DOI: 10.1038/mtna.2012.8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Small noncoding RNAs (ncRNAs) have been shown to guide epigenetic silencing complexes to target loci in human cells. When targeted to gene promoters, these small RNAs can lead to long-term stable epigenetic silencing of gene transcription. To date, small RNAs have been shown to modulate transcriptional gene silencing (TGS) of human immunodeficiency virus type 1 (HIV-1) as well as several other disease-related genes, but it has remained unknown as to what extent particular chemistries can be used to generate single-stranded backbone-modified oligonucleotides that are amenable to this form of gene targeting and regulation. Here, we present data indicating that specific combinations of backbone modifications can be used to generate single-stranded antisense oligonucleotides that can functionally direct TGS of HIV-1 in a manner that is however, independent of epigenetic changes at the target loci. Furthermore, this functionality appears contingent on the absence of a 5' phosphate in the oligonucleotide. These data suggest that chemically modified oligonucleotide based approaches could be implemented as a means to regulate gene transcription in an epigenetically independent manner.
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Affiliation(s)
- Stuart Knowling
- Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California, USA
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12
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Abstract
A brief historical introduction describes early attempts to silence specific genes using the antisense oligonucleotides that flourished in the 1980s. Early aspirations for therapeutic applications were almost extinguished by the unexpected complexity of oligonucleotide pharmacology. Once the biochemistry and molecular biology behind some of the pharmacology was worked out, new approaches became apparent for using oligonucleotides to treat disease. The biochemistry of small nucleic acids is outlined in Section 2. Various approaches employing oligonucleotides to control cellular functions are reviewed in Section 3. These include antisense oligonucleotides and siRNA that bind to RNA, antigene oligonucleotides that bind to DNA, and aptamers, decoys, and CpG oligonucleotides that bind to proteins.
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MESH Headings
- Aptamers, Nucleotide/chemistry
- Aptamers, Nucleotide/pharmacology
- Aptamers, Nucleotide/therapeutic use
- Communicable Diseases/drug therapy
- Communicable Diseases/pathology
- CpG Islands
- DNA/chemistry
- DNA/metabolism
- DNA, Catalytic/chemistry
- DNA, Catalytic/pharmacology
- DNA, Catalytic/therapeutic use
- Diabetes Mellitus/drug therapy
- Diabetes Mellitus/pathology
- Humans
- MicroRNAs/chemistry
- MicroRNAs/pharmacology
- MicroRNAs/therapeutic use
- Molecular Targeted Therapy/methods
- Neoplasms/drug therapy
- Neoplasms/pathology
- Neurodegenerative Diseases/drug therapy
- Neurodegenerative Diseases/pathology
- Nucleic Acid Hybridization
- Oligonucleotides/chemistry
- Oligonucleotides/pharmacology
- Oligonucleotides/therapeutic use
- Oligonucleotides, Antisense/chemistry
- Oligonucleotides, Antisense/pharmacology
- Oligonucleotides, Antisense/therapeutic use
- RNA, Catalytic/chemistry
- RNA, Catalytic/pharmacology
- RNA, Catalytic/therapeutic use
- RNA, Small Interfering/chemistry
- RNA, Small Interfering/pharmacology
- RNA, Small Interfering/therapeutic use
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Affiliation(s)
- John Goodchild
- Department of Chemistry, Worcester State University, Worcester, MA 01602-2597, USA.
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13
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Lamers F, van der Ploeg I, Schild L, Ebus ME, Koster J, Hansen BR, Koch T, Versteeg R, Caron HN, Molenaar JJ. Knockdown of survivin (BIRC5) causes apoptosis in neuroblastoma via mitotic catastrophe. Endocr Relat Cancer 2011; 18:657-68. [PMID: 21859926 DOI: 10.1530/erc-11-0207] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BIRC5 (survivin) is one of the genes located on chromosome arm 17q in the region that is often gained in neuroblastoma. BIRC5 is a protein in the intrinsic apoptotic pathway that interacts with XIAP and DIABLO leading to caspase-3 and caspase-9 inactivation. BIRC5 is also involved in stabilizing the microtubule-kinetochore dynamics. Based on the Affymetrix mRNA expression data, we here show that BIRC5 expression is strongly upregulated in neuroblastoma compared with normal tissues, adult malignancies, and non-malignant fetal adrenal neuroblasts. The over-expression of BIRC5 correlates with an unfavorable prognosis independent of the presence of 17q gain. Silencing of BIRC5 in neuroblastoma cell lines by various antisense molecules resulted in massive apoptosis as measured by PARP cleavage and FACS analysis. As both the intrinsic apoptotic pathway and the chromosomal passenger complex can be therapeutically targeted, we investigated in which of them BIRC5 exerted its essential anti-apoptotic role. Immunofluorescence analysis of neuroblastoma cells after BIRC5 silencing showed formation of multinucleated cells indicating mitotic catastrophe, which leads to apoptosis via P53 and CASP2. We show that BIRC5 silencing indeed resulted in activation of P53 and we could rescue apoptosis by CASP2 inhibition. We conclude that BIRC5 stabilizes the microtubules in the chromosomal passenger complex in neuroblastoma and that the apoptotic response results from mitotic catastrophe, which makes BIRC5 an interesting target for therapy.
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Affiliation(s)
- Fieke Lamers
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Meibergdreef 15, PO Box 22700, 1105 AZ Amsterdam, The Netherlands
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14
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Ma DL, Chan DSH, Lee P, Kwan MHT, Leung CH. Molecular modeling of drug–DNA interactions: Virtual screening to structure-based design. Biochimie 2011; 93:1252-66. [PMID: 21514356 DOI: 10.1016/j.biochi.2011.04.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 04/01/2011] [Indexed: 12/11/2022]
Affiliation(s)
- Dik-Lung Ma
- Department of Chemistry, Hong Kong Baptist University, Hong Kong, China.
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15
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Gagnon KT, Watts JK, Pendergraff HM, Montaillier C, Thai D, Potier P, Corey DR. Antisense and antigene inhibition of gene expression by cell-permeable oligonucleotide-oligospermine conjugates. J Am Chem Soc 2011; 133:8404-7. [PMID: 21539318 PMCID: PMC3106116 DOI: 10.1021/ja200312y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Oligonucleotides and their derivatives are a proven chemical strategy for modulating gene expression. However, their negative charge remains a challenge for delivery and target recognition inside cells. Here we show that oligonucleotide-oligospermine conjugates (Zip nucleic acids or ZNAs) can help overcome these shortcomings by serving as effective antisense and antigene agents. Conjugates containing DNA and locked nucleic acid (LNA) oligonucleotides are active, and oligospermine conjugation facilitates carrier-free cell uptake at nanomolar concentrations. Conjugates targeting the CAG triplet repeat within huntingtin (HTT) mRNA selectively inhibit expression of the mutant huntingtin protein. Conjugates targeting the promoter of the progesterone receptor (PR) function as antigene agents to block PR expression. These observations support further investigation of ZNA conjugates as gene silencing agents.
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Affiliation(s)
- Keith T. Gagnon
- Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | - Jonathan K. Watts
- Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | - Hannah M. Pendergraff
- Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
| | | | - Danielle Thai
- SIGMA Custom Products, Genopole Campus 1, 5 rue Desbruères, 91030 Evry Cedex, France
| | - Pierre Potier
- SIGMA Custom Products, Genopole Campus 1, 5 rue Desbruères, 91030 Evry Cedex, France
| | - David R. Corey
- Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, 75390, USA
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16
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Campbell MA, Wengel J. Locked vs. unlocked nucleic acids (LNA vs. UNA): contrasting structures work towards common therapeutic goals. Chem Soc Rev 2011; 40:5680-9. [PMID: 21556437 DOI: 10.1039/c1cs15048k] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Oligonucleotide chemistry has been developed greatly over the past three decades, with many advances in increasing nuclease resistance, enhancing duplex stability and assisting with cellular uptake. Locked nucleic acid (LNA) is a structurally rigid modification that increases the binding affinity of a modified-oligonucleotide. In contrast, unlocked nucleic acid (UNA) is a highly flexible modification, which can be used to modulate duplex characteristics. In this tutorial review, we will compare the synthetic routes to both of these modifications, contrast the structural features, examine the hybridization properties of LNA and UNA modified duplexes, and discuss how they have been applied within biotechnology and drug research. LNA has found widespread use in antisense oligonucleotide technology, where it can stabilize interactions with target RNA and protect from cellular nucleases. The newly emerging field of siRNAs has made use of LNA and, recently, also UNA. These modifications are able to increase double-stranded RNA stability in serum and decrease off-target effects seen with conventional siRNAs. LNA and UNA are also emerging as versatile modifications for aptamers. Their application to known aptamer structures has opened up the possibility of future selection of LNA-modified aptamers. Each of these oligonucleotide technologies has the potential to become a new type of therapy to treat a wide variety of diseases, and LNA and UNA will no doubt play a part in future developments of therapeutic and diagnostic oligonucleotides.
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Affiliation(s)
- Meghan A Campbell
- Nucleic Acid Center, Institute for Physics and Chemistry, University of Southern Denmark, Odense, Denmark
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17
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Zaghloul EM, Madsen AS, Moreno PMD, Oprea II, El-Andaloussi S, Bestas B, Gupta P, Pedersen EB, Lundin KE, Wengel J, Smith CIE. Optimizing anti-gene oligonucleotide 'Zorro-LNA' for improved strand invasion into duplex DNA. Nucleic Acids Res 2010; 39:1142-54. [PMID: 20860997 PMCID: PMC3035455 DOI: 10.1093/nar/gkq835] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Zorro-LNA (Zorro) is a newly developed, oligonucleotide (ON)-based, Z-shaped construct with the potential of specific binding to each strand of duplex DNA. The first-generation Zorros are formed by two hybridized LNA/DNA mixmers (2-ON Zorros) and was hypothesized to strand invade. We have now established a method, which conclusively demonstrates that an LNA ON can strand invade into duplex DNA. To make Zorros smaller in size and easier to design, we synthesized 3′–5′–5′–3′ single-stranded Zorro-LNA (ssZorro) by using both 3′- and 5′-phosphoramidites. With ssZorro, a significantly greater extent and rate of double-strand invasion (DSI) was obtained than with conventional 2-ON Zorros. Introducing hydrophilic PEG-linkers connecting the two strands did not significantly change the rate or extent of DSI as compared to ssZorro with a nucleotide-based linker, while the longest alkyl-chain linker tested (36 carbons) resulted in a very slow DSI. The shortest alkyl-chain linker (3 carbons) did not reduce the extent of DSI of ssZorro, but significantly decreased the DSI rate. Collectively, ssZorro is smaller in size, easier to design and more efficient than conventional 2-ON Zorro in inducing DSI. Analysis of the chemical composition of the linker suggests that it could be of importance for future therapeutic considerations.
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Affiliation(s)
- Eman M Zaghloul
- Department of Laboratory Medicine, Karolinska Institutet, 141 86 Huddinge, Stockholm, Sweden.
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18
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Rodríguez-Martínez JA, Peterson-Kaufman KJ, Ansari AZ. Small-molecule regulators that mimic transcription factors. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1799:768-74. [PMID: 20804876 DOI: 10.1016/j.bbagrm.2010.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 08/17/2010] [Accepted: 08/22/2010] [Indexed: 02/06/2023]
Abstract
Transcription factors (TFs) are responsible for decoding and expressing the information stored in the genome, which dictates cellular function. Creating artificial transcription factors (ATFs) that mimic endogenous TFs is a major goal at the interface of biology, chemistry, and molecular medicine. Such molecular tools will be essential for deciphering and manipulating transcriptional networks that lead to particular cellular states. In this minireview, the framework for the design of functional ATFs is presented and current challenges in the successful implementation of ATFs are discussed.
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19
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Chu Y, Yue X, Younger ST, Janowski BA, Corey DR. Involvement of argonaute proteins in gene silencing and activation by RNAs complementary to a non-coding transcript at the progesterone receptor promoter. Nucleic Acids Res 2010; 38:7736-48. [PMID: 20675357 PMCID: PMC2995069 DOI: 10.1093/nar/gkq648] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Double-stranded RNAs that are complementary to non-coding transcripts at gene promoters can activate or inhibit gene expression in mammalian cells. Understanding the mechanism for modulating gene expression by promoter-targeted antigene RNAs (agRNAs) will require identification of the proteins involved in recognition. Previous reports have implicated argonaute (AGO) proteins, but identifications have differed with involvement of AGO1, AGO2, or both AGO1 and AGO2 being reported by different studies. The roles of AGO3 and AGO4 have not been investigated. Here, we examine the role of AGO 1–4 in gene silencing and activation of the progesterone receptor (PR) gene. Expression of AGO2 is necessary for efficient gene silencing or activation and AGO2 is recruited to the non-coding transcript that overlaps the promoter during both gene silencing and activation. Expression of AGO1, AGO3 and AGO4 are not necessary for gene silencing or activation nor are AGO1, AGO3, or AGO4 recruited to the target non-coding transcript during gene activation. These data indicate that AGO2 is the primary AGO variant involved in modulating expression of PR by agRNAs.
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Affiliation(s)
- Yongjun Chu
- Department of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA
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20
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Watts JK, Yu D, Charisse K, Montaillier C, Potier P, Manoharan M, Corey DR. Effect of chemical modifications on modulation of gene expression by duplex antigene RNAs that are complementary to non-coding transcripts at gene promoters. Nucleic Acids Res 2010; 38:5242-59. [PMID: 20403811 PMCID: PMC2926613 DOI: 10.1093/nar/gkq258] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Antigene RNAs (agRNAs) are small RNA duplexes that target non-coding transcripts rather than mRNA and specifically suppress or activate gene expression in a sequence-dependent manner. For many applications in vivo, it is likely that agRNAs will require chemical modification. We have synthesized agRNAs that contain different classes of chemical modification and have tested their ability to modulate expression of the human progesterone receptor gene. We find that both silencing and activating agRNAs can retain activity after modification. Both guide and passenger strands can be modified and functional agRNAs can contain 2'F-RNA, 2'OMe-RNA, and locked nucleic acid substitutions, or combinations of multiple modifications. The mechanism of agRNA activity appears to be maintained after chemical modification: both native and modified agRNAs modulate recruitment of RNA polymerase II, have the same effect on promoter-derived antisense transcripts, and must be double-stranded. These data demonstrate that agRNA activity is compatible with a wide range of chemical modifications and may facilitate in vivo applications.
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Affiliation(s)
- Jonathan K Watts
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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21
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Sau SP, Kumar TS, Hrdlicka PJ. Invader LNA: efficient targeting of short double stranded DNA. Org Biomol Chem 2010; 8:2028-36. [PMID: 20401378 DOI: 10.1039/b923465a] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Despite progress with triplex-forming oligonucleotides or helix-invading peptide nucleic acids (PNAs), there remains a need for probes facilitating sequence-unrestricted targeting of double stranded DNA (dsDNA) at physiologically relevant conditions. Invader LNA probes, i.e., DNA duplexes with "+1 interstrand zipper arrangements" of intercalator-functionalized 2'-amino-alpha-l-LNA monomers, are demonstrated herein to recognize short mixed sequence dsDNA targets. This approach, like pseudo-complementary PNA (pcPNA), relies on relative differences in stability between probe duplexes and the corresponding probe:target duplexes for generation of a favourable thermodynamic gradient. Unlike pcPNA, Invader LNA probes take advantage of the "nearest neighbour exclusion principle", i.e., intercalating units of Invader LNA monomers are poorly accommodated in probe duplexes but extraordinarily well tolerated in probe-target duplexes (DeltaT(m)/modification up to +11.5 degrees C). Recognition of isosequential dsDNA-targets occurs: a) at experimental temperatures much lower than the thermal denaturation temperatures (T(m)'s) of Invader LNAs or dsDNA-targets, b) at a wide range of ionic strengths, and c) with good mismatch discrimination. Recognition of dsDNA is monitored in real-time using inherent pyrene-pyrene excimer signals of Invader LNA probes, which provides insights into reaction kinetics and enables rational design of probes. These properties render Invader LNAs as promising probes for biomedical applications entailing sequence-unrestricted recognition of dsDNA.
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Affiliation(s)
- Sujay P Sau
- Department of Chemistry, University of Idaho, Moscow, ID 83844-2343, USA
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22
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Lundin KE, Simonson OE, Moreno PMD, Zaghloul EM, Oprea II, Svahn MG, Smith CIE. Nanotechnology approaches for gene transfer. Genetica 2009; 137:47-56. [PMID: 19488829 DOI: 10.1007/s10709-009-9372-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 05/14/2009] [Indexed: 01/07/2023]
Abstract
In both basic research as well as experimental gene therapy the need to transfer genetic material into a cell is of vital importance. The cellular compartment, which is the target for the genetic material, depends upon application. An siRNA that mediates silencing is preferably delivered to the cytosol while a transgene would need to end up in the nucleus for successful transcription to occur. Furthermore the ability to regulate gene expression has grown substantially since the discovery of RNA interference. In such diverse fields as medical research and agricultural pest control, the capability to alter the genetic output has been a useful tool for pushing the scientific frontiers. This review is focused on nanotechnological approaches to assemble optimised structures of nucleic acid derivatives to facilitate gene delivery as well as promoting down regulation of endogenous genes.
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Affiliation(s)
- Karin E Lundin
- Department of Laboratory Medicine, Clinical Research Center, Karolinska Institutet, Karolinska University Hospital, 141 86 Huddinge, Sweden.
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23
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Beane R, Gabillet S, Montaillier C, Arar K, Corey DR. Recognition of chromosomal DNA inside cells by locked nucleic acids. Biochemistry 2009; 47:13147-9. [PMID: 19053275 DOI: 10.1021/bi801930p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sequence-selective recognition of DNA inside cells by oligonucleotides would provide valuable insights into cellular processes and new leads for therapeutics. Recent work, however, has shown that noncoding RNA transcripts overlap chromosomal DNA. These RNAs provide alternate targets for oligonucleotides designed to bind promoter DNA, potentially overturning previous assumptions about mechanism. Here, we show that antigene locked nucleic acids (agLNAs) reduce RNA levels of targeted genes, block RNA polymerase and transcription factor association at gene promoters, and bind to chromosomal DNA. These data suggest that the mechanism of LNAs involves recognition of chromosomal DNA and that LNAs are bona fide antigene molecules.
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Affiliation(s)
- Randall Beane
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Road, Dallas, Texas 75390-9041, USA
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24
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Simon P, Cannata F, Concordet JP, Giovannangeli C. Targeting DNA with triplex-forming oligonucleotides to modify gene sequence. Biochimie 2008; 90:1109-16. [PMID: 18460344 DOI: 10.1016/j.biochi.2008.04.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Accepted: 04/14/2008] [Indexed: 12/19/2022]
Abstract
Molecules that interact with DNA in a sequence-specific manner are attractive tools for manipulating gene sequence and expression. For example, triplex-forming oligonucleotides (TFOs), which bind to oligopyrimidine.oligopurine sequences via Hoogsteen hydrogen bonds, have been used to inhibit gene expression at the DNA level as well as to induce targeted mutagenesis in model systems. Recent advances in using oligonucleotides and analogs to target DNA in a sequence-specific manner will be discussed. In particular, chemical modification of TFOs has been used to improve binding to chromosomal target sequences in living cells. Various oligonucleotide analogs have also been found to expand the range of sequences amenable to manipulation, including so-called "Zorro" locked nucleic acids (LNAs) and pseudo-complementary peptide nucleic acids (pcPNAs). Finally, we will examine the potential of TFOs for directing targeted gene sequence modification and propose that synthetic nucleases, based on conjugation of sequence-specific DNA ligands to DNA damaging molecules, are a promising alternative to protein-based endonucleases for targeted gene sequence modification.
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Affiliation(s)
- Philippe Simon
- Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, USM 503, 43 rue Cuvier, 75005 Paris, France
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25
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Ge R, Svahn MG, Simonson OE, Mohamed AJ, Lundin KE, Smith CIE. Sequence-specific inhibition of RNA polymerase III-dependent transcription using Zorro locked nucleic acid (LNA). J Gene Med 2008; 10:101-9. [PMID: 18023071 DOI: 10.1002/jgm.1124] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND RNA polymerase III (pol III)-dependent transcripts are involved in many fundamental activities in a cell, such as splicing and protein synthesis. They also regulate cell growth and influence tumor formation. During recent years vector-based systems for expression of short hairpin (sh) RNA under the control of a pol III promoter have been developed as gene-based medicines. Therefore, there is an increasing interest in means to regulate pol III-dependent transcription. Recently, we have developed a novel anti-gene molecule 'Zorro LNA (Locked Nucleic Acid)', which simultaneously hybridizes to both strands of super-coiled DNA and potently inhibits RNA polymerase II-derived transcription. We have now applied Zorro LNA in an attempt to also control U6 promoter-driven expression of shRNA. METHODS In this study, we constructed pshluc and pshluc2BS plasmids, in which U6 promoter-driven small hairpin RNA specific for luciferase gene (shluc) was without or with Zorro LNA binding sites, respectively. After hybridization of Zorro LNA to pshluc2BS, the LNA-bound plasmid was cotransfected with pEGFPluc into mammalian cells and into a mouse model. In cellular experiments, cotransfection of unhybridized pshluc2BS, Zorro LNA and pEGFPluc was also performed. RESULTS The results showed that the Zorro LNA construct efficiently inhibited pol III-dependent transcription as an anti-gene reagent in a cellular context, including in vivo in a mouse model. CONCLUSIONS Thus, this new form of gene silencer 'Zorro LNA' could potentially serve as a versatile regulator of pol III-dependent transcription, including various forms of shRNAs.
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Affiliation(s)
- Rongbin Ge
- Clinical Research Center, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, SE-141 86 Stockholm, Sweden
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26
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Jain A, Wang G, Vasquez KM. DNA triple helices: biological consequences and therapeutic potential. Biochimie 2008; 90:1117-30. [PMID: 18331847 DOI: 10.1016/j.biochi.2008.02.011] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 02/08/2008] [Indexed: 01/25/2023]
Abstract
DNA structure is a critical element in determining its function. The DNA molecule is capable of adopting a variety of non-canonical structures, including three-stranded (i.e. triplex) structures, which will be the focus of this review. The ability to selectively modulate the activity of genes is a long-standing goal in molecular medicine. DNA triplex structures, either intermolecular triplexes formed by binding of an exogenously applied oligonucleotide to a target duplex sequence, or naturally occurring intramolecular triplexes (H-DNA) formed at endogenous mirror repeat sequences, present exploitable features that permit site-specific alteration of the genome. These structures can induce transcriptional repression and site-specific mutagenesis or recombination. Triplex-forming oligonucleotides (TFOs) can bind to duplex DNA in a sequence-specific fashion with high affinity, and can be used to direct DNA-modifying agents to selected sequences. H-DNA plays important roles in vivo and is inherently mutagenic and recombinogenic, such that elements of the H-DNA structure may be pharmacologically exploitable. In this review we discuss the biological consequences and therapeutic potential of triple helical DNA structures. We anticipate that the information provided will stimulate further investigations aimed toward improving DNA triplex-related gene targeting strategies for biotechnological and potential clinical applications.
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Affiliation(s)
- Aklank Jain
- Department of Carcinogenesis, University of Texas, M.D. Anderson Cancer Center, Science Park--Research Division, 1808 Park Road 1-C, P.O. Box 389, Smithville, TX 78957, USA
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27
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Hu J, Corey DR. Inhibiting gene expression with peptide nucleic acid (PNA)--peptide conjugates that target chromosomal DNA. Biochemistry 2007; 46:7581-9. [PMID: 17536840 PMCID: PMC2564818 DOI: 10.1021/bi700230a] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Peptide nucleic acids (PNAs) are nonionic DNA/RNA mimics that can recognize complementary sequences by Watson-Crick base pairing. The neutral PNA backbone facilitates the recognition of duplex DNA by strand invasion, suggesting that antigene PNAs (agPNAs) can be important tools for exploring the structure and function of chromosomal DNA inside cells. However, before agPNAs can enter wide use, it will be necessary to develop straightforward strategies for introducing them into cells. Here, we demonstrate that agPNA-peptide conjugates can target promoter DNA and block progesterone receptor (PR) gene expression inside cells. Thirty-six agPNA-peptide conjugates were synthesized and tested. We observed inhibition of gene expression using cationic peptides containing either arginine or lysine residues, with eight or more cationic amino acids being preferred. Both 13 and 19 base agPNA-peptide conjugates were inhibitory. Inhibition was observed in human cancer cell lines expressing either high or low levels of progesterone receptor. Modification of agPNA-peptide conjugates with hydrophobic amino acids or small molecule hydrophobic moieties yielded improved potency. Inhibition by agPNAs did not require cationic lipid or any other additive, but adding agents to cell growth media that promote endosomal release caused modest increases in agPNA potency. These data demonstrate that chromosomal DNA is accessible to agPNA-peptide conjugates and that chemical modifications can improve potency.
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Affiliation(s)
- Jiaxin Hu
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Road, Dallas, Texas 75390-9041, USA
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