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Stanek KA, Mura C. Producing Hfq/Sm Proteins and sRNAs for Structural and Biophysical Studies of Ribonucleoprotein Assembly. Methods Mol Biol 2019; 1737:273-299. [PMID: 29484599 DOI: 10.1007/978-1-4939-7634-8_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hfq is a bacterial RNA-binding protein that plays key roles in the post-transcriptional regulation of gene expression. Like other Sm proteins, Hfq assembles into toroidal discs that bind RNAs with varying affinities and degrees of sequence specificity. By simultaneously binding to a regulatory small RNA (sRNA) and an mRNA target, Hfq hexamers facilitate productive RNA∙∙∙RNA interactions; the generic nature of this chaperone-like functionality makes Hfq a hub in many sRNA-based regulatory networks. That Hfq is crucial in diverse cellular pathways-including stress response, quorum sensing, and biofilm formation-has motivated genetic and "RNAomic" studies of its function and physiology (in vivo), as well as biochemical and structural analyses of Hfq∙∙∙RNA interactions (in vitro). Indeed, crystallographic and biophysical studies first established Hfq as a member of the phylogenetically conserved Sm superfamily. Crystallography and other biophysical methodologies enable the RNA-binding properties of Hfq to be elucidated in atomic detail, but such approaches have stringent sample requirements, viz.: reconstituting and characterizing an Hfq·RNA complex requires ample quantities of well-behaved (sufficient purity, homogeneity) specimens of Hfq and RNA (sRNA, mRNA fragments, short oligoribonucleotides, or even single nucleotides). The production of such materials is covered in this chapter, with a particular focus on recombinant Hfq proteins for crystallization experiments.
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Affiliation(s)
- Kimberly A Stanek
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA.
| | - Cameron Mura
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA.
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202
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203
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Identification of Long Noncoding RNA-Protein Interactions Through In Vitro RNA Pull-Down Assay with Plant Nuclear Extracts. Methods Mol Biol 2019; 1933:279-288. [PMID: 30945192 DOI: 10.1007/978-1-4939-9045-0_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent advances in next-generation sequencing have revealed that majority of the plant genome is transcribed into long noncoding RNA (lncRNA). Many lncRNAs function by interacting with proteins and forming regulatory complexes. RNA-protein interactions are vital in controlling core cellular processes like transcription and translation. Therefore, identifying proteins that interact with lncRNAs is the first step to deciphering lncRNA functions. Here, we describe an RNA-protein pull-down assay, which enables the identification of proteins that interact with an RNA under study. As an example, we describe pull-down of proteins interacting with lncRNA ELENA1, which promotes the enrichment of MED19a on PR1 promoter to activate PR1 expression.
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204
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Jones CP, Piszczek G, Ferré-D'Amaré AR. Isothermal Titration Calorimetry Measurements of Riboswitch-Ligand Interactions. Methods Mol Biol 2019; 1964:75-87. [PMID: 30929236 DOI: 10.1007/978-1-4939-9179-2_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
One of the many ways by which bacteria control gene expression is through cis-acting regulatory mRNA elements called riboswitches. By specifically binding to small molecules or metabolites and pairing the binding event to an RNA structure change, riboswitches link a metabolic input to a transcriptional or translational output. For over a decade, isothermal titration calorimetry (ITC) has been used to investigate how riboswitches interact with small molecules. We present methods for assaying RNA-ligand interactions using ITC and analyzing resulting data to estimate thermodynamic parameters associated with binding.
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Affiliation(s)
- Christopher P Jones
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Grzegorz Piszczek
- Biophysics Core Facility, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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205
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Fujimura T, Esteban R. The cap-snatching reaction of yeast L-A double-stranded RNA virus is reversible and the catalytic sites on both Gag and the Gag domain of Gag-Pol are active. Mol Microbiol 2018; 111:395-404. [PMID: 30427078 DOI: 10.1111/mmi.14161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2018] [Indexed: 02/01/2023]
Abstract
The yeast L-A double-stranded RNA virus synthesizes capped transcripts by a unique cap-snatching mechanism in which the m7 Gp moiety of host mRNA (donor) is transferred to the diphosphorylated 5' end of the viral transcript (acceptor). This reaction is activated by viral transcription. Here, we show that cap snatching can be reversible. Because only m7 Gp is transferred during the reaction, the resulting decapped donor, as expected, retained diphosphates at the 5' end. We also found that the 5' terminal nucleotide of the acceptor needs to be G but not A. Interestingly, the A-initiated molecule when equipped with a cap structure (m7 GpppA…) could work as cap donor. Because the majority of host mRNAs in yeast have A after the cap structures at the 5' ends, this finding implies that cap-snatching in vivo is virtually a one-way reaction, in favor of furnishing the viral transcript with a cap. The cap-snatching sites are located on the coat protein Gag and also the Gag domain of Gag-Pol. Here, we demonstrate that both sites are functional, indicating that activation of cap snatching by transcription is not transmitted through the peptide bonding between the Gag and Pol domains of Gag-Pol.
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Affiliation(s)
- Tsutomu Fujimura
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, Salamanca, Spain
| | - Rosa Esteban
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca, Salamanca, Spain
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206
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Welty R, Pabit SA, Katz AM, Calvey GD, Pollack L, Hall KB. Divalent ions tune the kinetics of a bacterial GTPase center rRNA folding transition from secondary to tertiary structure. RNA (NEW YORK, N.Y.) 2018; 24:1828-1838. [PMID: 30254137 PMCID: PMC6239185 DOI: 10.1261/rna.068361.118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/20/2018] [Indexed: 05/22/2023]
Abstract
Folding of an RNA from secondary to tertiary structure often depends on divalent ions for efficient electrostatic charge screening (nonspecific association) or binding (specific association). To measure how different divalent cations modify folding kinetics of the 60 nucleotide Ecoli rRNA GTPase center, we combined stopped-flow fluorescence in the presence of Mg2+, Ca2+, or Sr2+ together with time-resolved small angle X-ray scattering (SAXS) in the presence of Mg2+ to observe the folding process. Immediately upon addition of each divalent ion, the RNA undergoes a transition from an extended state with secondary structure to a more compact structure. Subsequently, specific divalent ions modulate populations of intermediates in conformational ensembles along the folding pathway with transition times longer than 10 msec. Rate constants for the five folding transitions act on timescales from submillisecond to tens of seconds. The sensitivity of RNA tertiary structure to divalent cation identity affects all but the fastest events in RNA folding, and allowed us to identify those states that prefer Mg2+ The GTPase center RNA appears to have optimized its folding trajectory to specifically utilize this most abundant intracellular divalent ion.
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Affiliation(s)
- Robb Welty
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Suzette A Pabit
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Andrea M Katz
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - George D Calvey
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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207
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Kwiatkowska J, Wroblewska Z, Johnson KA, Olejniczak M. The binding of Class II sRNA MgrR to two different sites on matchmaker protein Hfq enables efficient competition for Hfq and annealing to regulated mRNAs. RNA (NEW YORK, N.Y.) 2018; 24:1761-1784. [PMID: 30217864 PMCID: PMC6239178 DOI: 10.1261/rna.067777.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 09/07/2018] [Indexed: 05/08/2023]
Abstract
MgrR is an Hfq-dependent sRNA, whose transcription is controlled by the level of Mg2+ ions in Escherichia coli MgrR belongs to Class II sRNAs because its stability in the cell is affected by mutations in Hfq differently than canonical, Class I sRNAs. Here, we examined the effect of mutations in RNA binding sites of Hfq on the kinetics of the annealing of MgrR to two different target mRNAs, eptB and ygdQ, by global data fitting of the reaction kinetics monitored by gel electrophoresis of intermediates and products. The data showed that the mutation on the rim of the Hfq ring trapped MgrR on Hfq preventing the annealing of MgrR to either mRNA. The mutation in the distal face slowed the ternary complex formation and affected the release of MgrR-mRNA complexes from Hfq, while the mutation in the proximal face weakened the MgrR binding to Hfq and in this way affected the annealing. Moreover, competition assays established that MgrR bound to both faces of Hfq and competed against other sRNAs. Further studies showed that uridine-rich sequences located in less structurally stable regions served as Hfq binding sites in each mRNA. Overall, the data show that the binding of MgrR sRNA to both faces of the Hfq ring enables it to efficiently anneal to target mRNAs. It also confers on MgrR a competitive advantage over other sRNAs, which could contribute to efficient cellular response to changes in magnesium homeostasis.
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Affiliation(s)
- Joanna Kwiatkowska
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Zuzanna Wroblewska
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
| | - Kenneth A Johnson
- Institute of Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, USA
| | - Mikolaj Olejniczak
- Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614 Poznań, Poland
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208
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Nomura Y, Roston D, Montemayor EJ, Cui Q, Butcher SE. Structural and mechanistic basis for preferential deadenylation of U6 snRNA by Usb1. Nucleic Acids Res 2018; 46:11488-11501. [PMID: 30215753 PMCID: PMC6265477 DOI: 10.1093/nar/gky812] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 01/08/2023] Open
Abstract
Post-transcriptional modification of snRNA is central to spliceosome function. Usb1 is an exoribonuclease that shortens the oligo-uridine tail of U6 snRNA, resulting in a terminal 2',3' cyclic phosphate group in most eukaryotes, including humans. Loss of function mutations in human Usb1 cause the rare disorder poikiloderma with neutropenia (PN), and result in U6 snRNAs with elongated 3' ends that are aberrantly adenylated. Here, we show that human Usb1 removes 3' adenosines with 20-fold greater efficiency than uridines, which explains the presence of adenylated U6 snRNAs in cells lacking Usb1. We determined three high-resolution co-crystal structures of Usb1: wild-type Usb1 bound to the substrate analog adenosine 5'-monophosphate, and an inactive mutant bound to RNAs with a 3' terminal adenosine and uridine. These structures, along with QM/MM MD simulations of the catalytic mechanism, illuminate the molecular basis for preferential deadenylation of U6 snRNA. The extent of Usb1 processing is influenced by the secondary structure of U6 snRNA.
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Affiliation(s)
- Yuichiro Nomura
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Daniel Roston
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Eric J Montemayor
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
- Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Qiang Cui
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
| | - Samuel E Butcher
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706, USA
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209
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Balaratnam S, West N, Basu S. A piRNA utilizes HILI and HIWI2 mediated pathway to down-regulate ferritin heavy chain 1 mRNA in human somatic cells. Nucleic Acids Res 2018; 46:10635-10648. [PMID: 30102404 PMCID: PMC6237762 DOI: 10.1093/nar/gky728] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 07/27/2018] [Accepted: 07/31/2018] [Indexed: 12/18/2022] Open
Abstract
The piwi interacting RNAs (piRNAs) are small non-coding RNAs that specifically bind to the PIWI proteins, a functional requirement. The piRNAs regulate germline development, transposons control, and gene expression. However, piRNA-mediated post-transcriptional gene regulation in human somatic cells is not well understood. We discovered a human piRNA (piR-FTH1) which has a complementary sequence in the ferritin heavy chain 1 (Fth1) mRNA. We demonstrated that expression of piR-FTH1 and Fth1 are inversely correlated in the tested tumor cell lines. We found that piR-FTH1 negatively regulates the Fth1 expression at post-transcriptional level in triple negative breast cancer (TNBC) cells. Additionally, we confirmed that transfected piR-FTH1 knocks down the Fth1 mRNA via the HIWI2 and HILI mediated mechanism. piR-FTH1 mediated Fth1 repression also increased doxorubicin sensitivity by a remarkable 20-fold in TNBC cells. Since the current piRNA-mediated knockdowns of target mRNA are mostly reported in germ line cells, piRNA-mediated post-transcriptional gene regulation in somatic cells is rather unique in its application and mechanistically uses an alternative pathway to siRNA and miRNA. This work begins to lay the groundwork with a broader impact on treatment of various diseases that are linked to elevated levels of specific mRNAs which have a piRNA target.
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Affiliation(s)
- Sumirtha Balaratnam
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Nicole West
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Soumitra Basu
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
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210
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Dai Y, Wynn JE, Peralta AN, Sherpa C, Jayaraman B, Li H, Verma A, Frankel AD, Le Grice SF, Santos WL. Discovery of a Branched Peptide That Recognizes the Rev Response Element (RRE) RNA and Blocks HIV-1 Replication. J Med Chem 2018; 61:9611-9620. [PMID: 30289719 PMCID: PMC6557124 DOI: 10.1021/acs.jmedchem.8b01076] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We synthesized and screened a unique 46 656-member library composed of unnatural amino acids that revealed several hits against RRE IIB RNA. Among the hit peptides identified, peptide 4A5 was found to be selective against competitor RNAs and inhibited HIV-1 Rev-RRE RNA interaction in cell culture in a p24 ELISA assay. Biophysical characterization in a ribonuclease protection assay suggested that 4A5 bound to the stem-loop region in RRE IIB while SHAPE MaP probing with 234 nt RRE RNA indicated additional interaction with secondary Rev binding sites. Taken together, our investigation suggests that HIV replication is inhibited by 4A5 blocking binding of Rev and subsequent multimerization.
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Affiliation(s)
- Yumin Dai
- Department of Chemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24060, United States
| | - Jessica E. Wynn
- Department of Chemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24060, United States
| | - Ashley N. Peralta
- Department of Chemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24060, United States
| | - Chringma Sherpa
- Basic Research Laboratory, National Cancer Institute, Frederick, Maryland, 21702, United States
| | - Bhargavi Jayaraman
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, 94158, United States
| | - Hao Li
- Department of Chemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24060, United States
| | - Astha Verma
- Department of Chemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24060, United States
| | - Alan D. Frankel
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, 94158, United States
| | - Stuart F. Le Grice
- Basic Research Laboratory, National Cancer Institute, Frederick, Maryland, 21702, United States
| | - Webster L. Santos
- Department of Chemistry and Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia, 24060, United States
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211
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A secondary structure within a human piRNA modulates its functionality. Biochimie 2018; 157:72-80. [PMID: 30414834 DOI: 10.1016/j.biochi.2018.11.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 11/04/2018] [Indexed: 01/30/2023]
Abstract
The piwi-interacting RNAs (piRNAs) are small non-coding RNAs, mostly 24-32 nucleotides in length. The piRNAs are not known to have any conserved secondary structure or sequence motifs. Using bioinformatics analysis, we discovered the presence of putative G-quadruplex (GQ) forming sequences in human piRNAs. We studied human piR-48164/piR-GQ containing a potential GQ forming sequence and using biochemical and biophysical techniques confirmed its ability to form a GQ. Using EMSA, we discovered that the formation of GQ structure led to inhibition of the piRNA binding to the HIWI-PAZ domain as well as the complementary base pairing to a target RNA. The inability of the piR-GQ to interact with the PIWI protein might be detrimental to the function of the piRNA. To investigate if the formation of a GQ structure in piRNA prevents its target gene silencing in vivo, we used a reporter assay. The piR-GQ failed to inhibit the reporter gene expression while a mutated version that lacked the ability to form GQ inhibited reporter gene expression indicating that the presence of GQ in piRNA is detrimental to its function. These studies unraveled the dependence of a piRNA's functionality on an RNA secondary structure and added a new layer of regulation to their function.
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212
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Nakamura A, Wang D, Komatsu Y. Molecular mechanism of substrate recognition and specificity of tRNA His guanylyltransferase during nucleotide addition in the 3'-5' direction. RNA (NEW YORK, N.Y.) 2018; 24:1583-1593. [PMID: 30111535 PMCID: PMC6191723 DOI: 10.1261/rna.067330.118] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/09/2018] [Indexed: 05/06/2023]
Abstract
The tRNAHis guanylyltransferase (Thg1) transfers a guanosine triphosphate (GTP) in the 3'-5' direction onto the 5'-terminal of tRNAHis, opposite adenosine at position 73 (A73). The guanosine at the -1 position (G-1) serves as an identity element for histidyl-tRNA synthetase. To investigate the mechanism of recognition for the insertion of GTP opposite A73, first we constructed a two-stranded tRNAHis molecule composed of a primer and a template strand through division at the D-loop. Next, we evaluated the structural requirements of the incoming GTP from the incorporation efficiencies of GTP analogs into the two-piece tRNAHis Nitrogen at position 7 and the 6-keto oxygen of the guanine base were important for G-1 addition; however, interestingly, the 2-amino group was found not to be essential from the highest incorporation efficiency of inosine triphosphate. Furthermore, substitution of the conserved A73 in tRNAHis revealed that the G-1 addition reaction was more efficient onto the template containing the opposite A73 than onto the template with cytidine (C73) or other bases forming canonical Watson-Crick base-pairing. Some interaction might occur between incoming GTP and A73, which plays a role in the prevention of continuous templated 3'-5' polymerization. This study provides important insights into the mechanism of accurate tRNAHis maturation.
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Affiliation(s)
- Akiyoshi Nakamura
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan
| | - Daole Wang
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yasuo Komatsu
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan
- Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
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213
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Belotserkovskii BP, Tornaletti S, D'Souza AD, Hanawalt PC. R-loop generation during transcription: Formation, processing and cellular outcomes. DNA Repair (Amst) 2018; 71:69-81. [PMID: 30190235 PMCID: PMC6340742 DOI: 10.1016/j.dnarep.2018.08.009] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
R-loops are structures consisting of an RNA-DNA duplex and an unpaired DNA strand. They can form during transcription upon nascent RNA "threadback" invasion into the DNA duplex to displace the non-template strand. Although R-loops occur naturally in all kingdoms of life and serve regulatory roles, they are often deleterious and can cause genomic instability. Of particular importance are the disastrous consequences when replication forks or transcription complexes collide with R-loops. The appropriate processing of R-loops is essential to avoid a number of human neurodegenerative and other clinical disorders. We provide a perspective on mechanistic aspects of R-loop formation and their resolution learned from studies in model systems. This should contribute to improved understanding of R-loop biological functions and enable their practical applications. We propose the novel employment of artificially-generated stable R-loops to selectively inactivate tumor cells.
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Affiliation(s)
- Boris P Belotserkovskii
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305-5020, United States
| | - Silvia Tornaletti
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305-5020, United States
| | - Alicia D D'Souza
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305-5020, United States
| | - Philip C Hanawalt
- Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA, 94305-5020, United States.
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214
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Structural Basis for tRNA Mimicry by a Bacterial Y RNA. Structure 2018; 26:1635-1644.e3. [PMID: 30318468 DOI: 10.1016/j.str.2018.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/03/2018] [Accepted: 09/10/2018] [Indexed: 12/29/2022]
Abstract
Noncoding Y RNAs are present in both animal cells and many bacteria. In all species examined, Y RNAs tether the Ro60 protein to an effector protein to perform various cellular functions. Recently, a new Y RNA subfamily was identified in bacteria. Bioinformatic analyses of these YrlA (Y RNA-like A) RNAs predict that the effector-binding domain resembles tRNA. We present the structure of this domain, the overall folding of which is strikingly similar to canonical tRNAs. The tertiary interactions that are responsible for stabilizing tRNA are present in YrlA, making it a close tRNA mimic. However, YrlA lacks a free CCA end and contains a kink in the stem corresponding to the anticodon stem. Since nucleotides in the D and T stems are conserved among YrlAs, they may be an interaction site for an unknown factor. Our experiments identify YrlA RNAs as a new class of tRNA mimics.
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215
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Borkotoky S, Murali A. The highly efficient T7 RNA polymerase: A wonder macromolecule in biological realm. Int J Biol Macromol 2018; 118:49-56. [DOI: 10.1016/j.ijbiomac.2018.05.198] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/25/2018] [Accepted: 05/26/2018] [Indexed: 12/01/2022]
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216
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Zhang J, Chetnani B, Cormack ED, Alonso D, Liu W, Mondragón A, Fei J. Specific structural elements of the T-box riboswitch drive the two-step binding of the tRNA ligand. eLife 2018; 7:39518. [PMID: 30251626 PMCID: PMC6197855 DOI: 10.7554/elife.39518] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/24/2018] [Indexed: 12/29/2022] Open
Abstract
T-box riboswitches are cis-regulatory RNA elements that regulate the expression of proteins involved in amino acid biosynthesis and transport by binding to specific tRNAs and sensing their aminoacylation state. While the T-box modular structural elements that recognize different parts of a tRNA have been identified, the kinetic trajectory describing how these interactions are established temporally remains unclear. Using smFRET, we demonstrate that tRNA binds to the riboswitch in two steps, first anticodon recognition followed by the sensing of the 3’ NCCA end, with the second step accompanied by a T-box riboswitch conformational change. Studies on site-specific mutants highlight that specific T-box structural elements drive the two-step binding process in a modular fashion. Our results set up a kinetic framework describing tRNA binding by T-box riboswitches, and suggest such binding mechanism is kinetically beneficial for efficient, co-transcriptional recognition of the cognate tRNA ligand. Living organisms depend upon a group of chemicals called amino acids to survive. Amino acids are the building blocks of proteins, and proteins have many important roles within and around cells. Bacteria regulate certain genes to ensure they have the right balance of different amino acids to survive. By controlling the availability of certain proteins that help them to make or collect certain amino acids, bacteria can control their overall amino acid balance. Before a protein is made, a molecular machine called RNA polymerase must first copy the information in a gene to make a molecule called a messenger RNA (mRNA). The mRNA is then translated to make the protein from individual amino acids. In this process, each amino acid needs to be first attached to another molecule called a transfer RNA (tRNA). In many bacteria species, the mRNAs involved in making or transporting amino acids contain structures called T-boxes. These structures guide the RNA polymerase to make more of the mRNAs when the levels of the amino acid become too low. A T-box, however, does not sense the level of the amino acid directly. Instead it senses the number of tRNA molecules that do not carry an amino acid. Zhang, Chetnani et al. examined a particular T-box interacting with tRNA using pairs of fluorescent dyes to detect distances between molecules. The T-box first recognizes a part of the tRNA called the anticodon to make sure it binds the correct type of tRNA. It then changes its shape to detect whether the tRNA is attached to an amino acid. This two-step process is driven by multiple structural elements within the T-box, and the flexibility of the T-box plays a critical role. A cell’s survival depends on it keeping amino acid levels under control. Understanding how bacteria do this could lead to new antibiotic drugs that target the T-box to kill cells. This study also provides insights into the workings of mRNA components like T-boxes – a type of riboswitch – which is an unusual means of controlling gene activity.
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Affiliation(s)
- Jiacheng Zhang
- Institute for Biophysical Dynamics, University of Chicago, Chicago, United States
| | - Bhaskar Chetnani
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | | | - Dulce Alonso
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Wei Liu
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, Evanston, United States
| | - Jingyi Fei
- Institute for Biophysical Dynamics, University of Chicago, Chicago, United States.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
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217
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Sarcar SN, Miller DL. A specific, promoter-independent activity of T7 RNA polymerase suggests a general model for DNA/RNA editing in single subunit RNA Polymerases. Sci Rep 2018; 8:13885. [PMID: 30224735 PMCID: PMC6141538 DOI: 10.1038/s41598-018-32231-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/31/2018] [Indexed: 01/23/2023] Open
Abstract
Insertional RNA editing has been observed and characterized in mitochondria of myxomycetes. The single subunit mitochondrial RNA polymerase adds nontemplated nucleotides co-transcriptionally to produce functional tRNA, rRNA and mRNAs with full genetic information. Addition of nontemplated nucleotides to the 3′ ends of RNAs have been observed in polymerases related to the mitochondrial RNA polymerase. This activity has been observed with T7 RNA polymerase (T7 RNAP), the well characterized prototype of the single subunit polymerases, as a nonspecific addition of nucleotides to the 3′ end of T7 RNAP transcripts in vitro. Here we show that this novel activity is an editing activity that can add specific ribonucleotides to 3′ ends of RNA or DNA when oligonucleotides, able to form intramolecular or intermolecular hairpin loops with recessed 3′ ends, are added to T7 RNA polymerase in the presence of at least one ribonucleotide triphosphate. Specific ribonucleotides are added to the recessed 3′ ends through Watson-Crick base pairing with the non-base paired nucleotide adjacent to the 3′ end. Optimization of this activity is obtained through alteration of the lengths of the 5′-extension, hairpin loop, and hairpin duplex. These properties define a T7 RNAP activity different from either transcriptional elongation or initiation.
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Affiliation(s)
- Subha Narayan Sarcar
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, 75083-0688, USA
| | - Dennis L Miller
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, Texas, 75083-0688, USA.
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218
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Wu W, Hatterschide J, Syu YC, Cantara WA, Blower RJ, Hanson HM, Mansky LM, Musier-Forsyth K. Human T-cell leukemia virus type 1 Gag domains have distinct RNA-binding specificities with implications for RNA packaging and dimerization. J Biol Chem 2018; 293:16261-16276. [PMID: 30217825 DOI: 10.1074/jbc.ra118.005531] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/13/2018] [Indexed: 12/14/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the first retrovirus that has conclusively been shown to cause human diseases. In HIV-1, specific interactions between the nucleocapsid (NC) domain of the Gag protein and genomic RNA (gRNA) mediate gRNA dimerization and selective packaging; however, the mechanism for gRNA packaging in HTLV-1, a deltaretrovirus, is unclear. In other deltaretroviruses, the matrix (MA) and NC domains of Gag are both involved in gRNA packaging, but MA binds nucleic acids with higher affinity and has more robust chaperone activity, suggesting that this domain may play a primary role. Here, we show that the MA domain of HTLV-1, but not the NC domain, binds short hairpin RNAs derived from the putative gRNA packaging signal. RNA probing of the HTLV-1 5' leader and cross-linking studies revealed that the primer-binding site and a region within the putative packaging signal form stable hairpins that interact with MA. In addition to a previously identified palindromic dimerization initiation site (DIS), we identified a new DIS in HTLV-1 gRNA and found that both palindromic sequences bind specifically the NC domain. Surprisingly, a mutant partially defective in dimer formation in vitro exhibited a significant increase in RNA packaging into HTLV-1-like particles, suggesting that efficient RNA dimerization may not be strictly required for RNA packaging in HTLV-1. Moreover, the lifecycle of HTLV-1 and other deltaretroviruses may be characterized by NC and MA functions that are distinct from those of the corresponding HIV-1 proteins, but together provide the functions required for viral replication.
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Affiliation(s)
- Weixin Wu
- From the Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus Ohio 43210 and
| | - Joshua Hatterschide
- From the Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus Ohio 43210 and
| | - Yu-Ci Syu
- From the Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus Ohio 43210 and
| | - William A Cantara
- From the Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus Ohio 43210 and
| | | | - Heather M Hanson
- Institute for Molecular Virology.,Molecular, Cellular, Developmental Biology and Genetics Graduate Program, and
| | - Louis M Mansky
- Institute for Molecular Virology.,Molecular, Cellular, Developmental Biology and Genetics Graduate Program, and.,Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455
| | - Karin Musier-Forsyth
- From the Department of Chemistry and Biochemistry, Center for Retrovirus Research, and Center for RNA Biology, The Ohio State University, Columbus Ohio 43210 and
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219
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Babina AM, Parker DJ, Li GW, Meyer MM. Fitness advantages conferred by the L20-interacting RNA cis-regulator of ribosomal protein synthesis in Bacillus subtilis. RNA (NEW YORK, N.Y.) 2018; 24:1133-1143. [PMID: 29925569 PMCID: PMC6097659 DOI: 10.1261/rna.065011.117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 06/18/2018] [Indexed: 05/09/2023]
Abstract
In many bacteria, ribosomal proteins autogenously repress their own expression by interacting with RNA structures typically located in the 5'-UTRs of their mRNA transcripts. This regulation is necessary to maintain a balance between ribosomal proteins and rRNA to ensure proper ribosome production. Despite advances in noncoding RNA discovery and validation of RNA-protein regulatory interactions, the selective pressures that govern the formation and maintenance of such RNA cis-regulators in the context of an organism remain largely undetermined. To examine the impact disruptions to this regulation have on bacterial fitness, we introduced point mutations that abolish ribosomal protein binding and regulation into the RNA structure that controls expression of ribosomal proteins L20 and L35 within the Bacillus subtilis genome. Our studies indicate that removing this regulation results in reduced log phase growth, improper rRNA maturation, and the accumulation of a kinetically trapped or misassembled ribosomal particle at low temperatures, suggesting defects in ribosome synthesis. Such work emphasizes the important role regulatory RNAs play in the stoichiometric production of ribosomal components for proper ribosome composition and overall organism viability and reinforces the potential of targeting ribosomal protein production and ribosome assembly with novel antimicrobials.
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Affiliation(s)
- Arianne M Babina
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Darren J Parker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Gene-Wei Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Michelle M Meyer
- Department of Biology, Boston College, Chestnut Hill, Massachusetts 02467, USA
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220
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Saramago M, Robledo M, Matos RG, Jiménez-Zurdo JI, Arraiano CM. Sinorhizobium meliloti RNase III: Catalytic Features and Impact on Symbiosis. Front Genet 2018; 9:350. [PMID: 30210532 PMCID: PMC6121014 DOI: 10.3389/fgene.2018.00350] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/09/2018] [Indexed: 11/13/2022] Open
Abstract
Members of the ribonuclease (RNase) III family of enzymes are metal-dependent double-strand specific endoribonucleases. They are ubiquitously found and eukaryotic RNase III-like enzymes include Dicer and Drosha, involved in RNA processing and RNA interference. In this work, we have addressed the primary characterization of RNase III from the symbiotic nitrogen-fixing α-proteobacterium Sinorhizobium meliloti. The S. meliloti rnc gene does encode an RNase III-like protein (SmRNase III), with recognizable catalytic and double-stranded RNA (dsRNA)-binding domains that clusters in a branch with its α–proteobacterial counterparts. Purified SmRNase III dimerizes, is active at neutral to alkaline pH and behaves as a strict metal cofactor-dependent double-strand endoribonuclease, with catalytic features distinguishable from those of the prototypical member of the family, the Escherichia coli ortholog (EcRNase III). SmRNase III prefers Mn2+ rather than Mg2+ as metal cofactor, cleaves the generic structured R1.1 substrate at a site atypical for RNase III cleavage, and requires higher cofactor concentrations and longer dsRNA substrates than EcRNase III for optimal activity. Furthermore, the ultraconserved E125 amino acid was shown to play a major role in the metal-dependent catalysis of SmRNase III. SmRNase III degrades endogenous RNA substrates of diverse biogenesis with different efficiency, and is involved in the maturation of the 23S rRNA. SmRNase III loss-of-function neither compromises viability nor alters morphology of S. meliloti cells, but influences growth, nodulation kinetics, the onset of nitrogen fixation and the overall symbiotic efficiency of this bacterium on the roots of its legume host, alfalfa, which ultimately affects plant growth. Our results support an impact of SmRNase III on nodulation and symbiotic nitrogen fixation in plants.
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Affiliation(s)
- Margarida Saramago
- Instituto de Tecnología Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Marta Robledo
- Grupo de Ecología Genética de la Rizosfera, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Rute G Matos
- Instituto de Tecnología Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - José I Jiménez-Zurdo
- Grupo de Ecología Genética de la Rizosfera, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Cecília M Arraiano
- Instituto de Tecnología Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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221
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Kocmik I, Piecyk K, Rudzinska M, Niedzwiecka A, Darzynkiewicz E, Grzela R, Jankowska-Anyszka M. Modified ARCA analogs providing enhanced translational properties of capped mRNAs. Cell Cycle 2018; 17:1624-1636. [PMID: 29954234 DOI: 10.1080/15384101.2018.1486164] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Nowadays gene manipulation techniques ("DNA therapy") undergo progressive development and become widely used in industry and medicine. Since new advances in mRNA technologies are capable for obtaining particles with increased stability and translational efficiency, RNA become an attractive alternative for advancement of DNA therapy. For the past years studies have been conducted to explore different modification in mRNA cap structure and its effect on RNA properties. Recently we have shown that modification of the cap structure at the N2 position of 7-methylguanosine leads to an enhancement in translation inhibition. Currently, we have decided to exploit translational properties of mRNA capped with the ARCA (anti-reversed cap) analogs modified within N2 position of purine moiety s. We designed and synthesized three new dinucleotide cap analogs and investigated them in the rabbit reticulocyte lysate (RRL) and the human embryonic kidney derived HEK293 cell line, in vitro translational model systems. The obtained data indicate that, in both translational assays, the cap analogs synthesized by us when incorporated into mRNA improved its translational properties compared to the ARCA capped transcripts. Furthermore, the introduced modifications enhanced stability of the capped transcripts in HEK293 cells, which become higher compared to that of the transcripts capped with regular cap or with ARCA. Additionally one of the synthesized cap analogs revealed strong translation inhibition potency in RRL system, with IC50 value 1.7 µM.
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Affiliation(s)
- Ilona Kocmik
- a Faculty of Chemistry , University of Warsaw , Warsaw , Poland
| | - Karolina Piecyk
- a Faculty of Chemistry , University of Warsaw , Warsaw , Poland
| | | | - Anna Niedzwiecka
- c Laboratory of Biological Physics , Institute of Physics, Polish Academy of Sciences , Warsaw , Poland
| | - Edward Darzynkiewicz
- b Centre of New Technologies , University of Warsaw , Warsaw , Poland.,d Division of Biophysics, Institute of Experimental Physics, Faculty of Physics , University of Warsaw , Warsaw , Poland
| | - Renata Grzela
- b Centre of New Technologies , University of Warsaw , Warsaw , Poland
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222
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Cotranscriptional 3'-End Processing of T7 RNA Polymerase Transcripts by a Smaller HDV Ribozyme. J Mol Evol 2018; 86:425-430. [PMID: 30099590 DOI: 10.1007/s00239-018-9861-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 07/28/2018] [Indexed: 10/28/2022]
Abstract
In vitro run-off transcription by T7 RNA polymerase generates heterogeneous 3'-ends because the enzyme tends to add untemplated adenylates. To generate homogeneous 3'-termini, HDV ribozymes have been used widely. Their sequences are added to the 3'-terminus such that co-transcriptional self-cleavage generates homogeneous 3'-ends. A shorter HDV sequence that cleaves itself efficiently would be advantageous. Here we show that a recently discovered, small HDV ribozyme is a good alternative to the previously used HDV ribozyme. The new HDV ribozyme is more efficient in some sequence contexts, and less efficient in other sequence contexts than the previously used HDV ribozyme. The smaller size makes the new HDV ribozyme a good alternative for transcript 3'-end processing.
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223
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Lee CH, Han SR, Lee SW. Group I Intron-Based Therapeutics Through Trans-Splicing Reaction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 159:79-100. [PMID: 30340790 DOI: 10.1016/bs.pmbts.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In 1982, the Cech group discovered that an intron structure in an rRNA precursor of Tetrahymena thermophila is sufficient to complete splicing without assistance from proteins. This was the first moment that scientists recognized RNAs can have catalytic activities derived from their own unique three-dimensional structures and thus play more various roles in biological processes than thought before. Several additional catalytic RNAs, called ribozymes, were subsequently identified in nature followed by intense studies to reveal their mechanisms of action and to engineer them for use in fields such as molecular cell biology, therapeutics, imaging, etc. Naturally occurring RNA-targeting ribozymes can be broadly classified into two categories by their abilities: Self-cleavage and self-splicing. Since ribozymes use base-pairing to recognize cleavage sites, identification of the catalytic center of naturally occurring ribozymes enables to engineer from "self" to "trans" acting ones which has accelerated to design and use ribozyme as valuable tools in gene therapy fields. Especially, group I intron-based trans-splicing ribozyme has unique property to use as a gene therapeutic agent. It can destroy and simultaneously repair (and/or reprogram) target RNAs to yield the desired therapeutic RNAs, maintaining endogenous spatial and temporal gene regulation of target RNAs. There have been progressive improvements in trans-splicing ribozymes and successful applications of these elements in gene therapy and molecular imaging approaches for various pathogenic conditions. In this chapter, current status of trans-splicing ribozyme therapeutics, focusing on Tetrahymena group I intron-based ribozymes, and their future prospects will be discussed.
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Affiliation(s)
- Chang Ho Lee
- Department of Integrated Life Sciences, Dankook University, Yongin, Republic of Korea
| | | | - Seong-Wook Lee
- Department of Integrated Life Sciences, Dankook University, Yongin, Republic of Korea; Rznomics Inc., Gwangju, Republic of Korea.
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224
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Marchanka A, Kreutz C, Carlomagno T. Isotope labeling for studying RNA by solid-state NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2018; 71:151-164. [PMID: 29651587 DOI: 10.1007/s10858-018-0180-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/07/2018] [Indexed: 06/08/2023]
Abstract
Nucleic acids play key roles in most biological processes, either in isolation or in complex with proteins. Often they are difficult targets for structural studies, due to their dynamic behavior and high molecular weight. Solid-state nuclear magnetic resonance spectroscopy (ssNMR) provides a unique opportunity to study large biomolecules in a non-crystalline state at atomic resolution. Application of ssNMR to RNA, however, is still at an early stage of development and presents considerable challenges due to broad resonances and poor dispersion. Isotope labeling, either as nucleotide-specific, atom-specific or segmental labeling, can resolve resonance overlaps and reduce the line width, thus allowing ssNMR studies of RNA domains as part of large biomolecules or complexes. In this review we discuss the methods for RNA production and purification as well as numerous approaches for isotope labeling of RNA. Furthermore, we give a few examples that emphasize the instrumental role of isotope labeling and ssNMR for studying RNA as part of large ribonucleoprotein complexes.
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Affiliation(s)
- Alexander Marchanka
- Centre for Biomolecular Drug Research (BMWZ) and Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 38, 30167, Hanover, Germany
| | - Christoph Kreutz
- Organic Chemistry, University of Innsbruck (CCB), Innrain 80/82, 6020, Innsbruck, Austria
| | - Teresa Carlomagno
- Centre for Biomolecular Drug Research (BMWZ) and Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 38, 30167, Hanover, Germany.
- Helmholtz Centre for Infection Research, Group of NMR-based Structural Chemistry, Inhoffenstraße 7, 38124, Brunswick, Germany.
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225
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Wienert B, Shin J, Zelin E, Pestal K, Corn JE. In vitro-transcribed guide RNAs trigger an innate immune response via the RIG-I pathway. PLoS Biol 2018; 16:e2005840. [PMID: 30011268 PMCID: PMC6049001 DOI: 10.1371/journal.pbio.2005840] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/01/2018] [Indexed: 02/08/2023] Open
Abstract
Clustered, regularly interspaced, short palindromic repeat (CRISPR)-CRISPR-associated 9 (Cas9) genome editing is revolutionizing fundamental research and has great potential for the treatment of many diseases. While editing of immortalized cell lines has become relatively easy, editing of therapeutically relevant primary cells and tissues can remain challenging. One recent advancement is the delivery of a Cas9 protein and an in vitro-transcribed (IVT) guide RNA (gRNA) as a precomplexed ribonucleoprotein (RNP). This approach allows editing of primary cells such as T cells and hematopoietic stem cells, but the consequences beyond genome editing of introducing foreign Cas9 RNPs into mammalian cells are not fully understood. Here, we show that the IVT gRNAs commonly used by many laboratories for RNP editing trigger a potent innate immune response that is similar to canonical immune-stimulating ligands. IVT gRNAs are recognized in the cytosol through the retinoic acid-inducible gene I (RIG-I) pathway but not the melanoma differentiation-associated gene 5 (MDA5) pathway, thereby triggering a type I interferon response. Removal of the 5'-triphosphate from gRNAs ameliorates inflammatory signaling and prevents the loss of viability associated with genome editing in hematopoietic stem cells. The potential for Cas9 RNP editing to induce a potent antiviral response indicates that care must be taken when designing therapeutic strategies to edit primary cells.
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Affiliation(s)
- Beeke Wienert
- Innovative Genomics Initiative, University of California, Berkeley, Berkeley, California, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Jiyung Shin
- Innovative Genomics Initiative, University of California, Berkeley, Berkeley, California, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Elena Zelin
- Innovative Genomics Initiative, University of California, Berkeley, Berkeley, California, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Kathleen Pestal
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Jacob E. Corn
- Innovative Genomics Initiative, University of California, Berkeley, Berkeley, California, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
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226
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Weber G, DeKoster GT, Holton N, Hall KB, Wahl MC. Molecular principles underlying dual RNA specificity in the Drosophila SNF protein. Nat Commun 2018; 9:2220. [PMID: 29880797 PMCID: PMC5992148 DOI: 10.1038/s41467-018-04561-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 05/02/2018] [Indexed: 12/22/2022] Open
Abstract
The first RNA recognition motif of the Drosophila SNF protein is an example of an RNA binding protein with multi-specificity. It binds different RNA hairpin loops in spliceosomal U1 or U2 small nuclear RNAs, and only in the latter case requires the auxiliary U2A' protein. Here we investigate its functions by crystal structures of SNF alone and bound to U1 stem-loop II, U2A' or U2 stem-loop IV and U2A', SNF dynamics from NMR spectroscopy, and structure-guided mutagenesis in binding studies. We find that different loop-closing base pairs and a nucleotide exchange at the tips of the loops contribute to differential SNF affinity for the RNAs. U2A' immobilizes SNF and RNA residues to restore U2 stem-loop IV binding affinity, while U1 stem-loop II binding does not require such adjustments. Our findings show how U2A' can modulate RNA specificity of SNF without changing SNF conformation or relying on direct RNA contacts.
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Affiliation(s)
- Gert Weber
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, D-14195, Berlin, Germany. .,Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Straße 15, D-12489, Berlin, Germany.
| | - Gregory T DeKoster
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri, 63110, USA
| | - Nicole Holton
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, D-14195, Berlin, Germany
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri, 63110, USA.
| | - Markus C Wahl
- Laboratory of Structural Biochemistry, Freie Universität Berlin, Takustraße 6, D-14195, Berlin, Germany. .,Helmholtz-Zentrum Berlin für Materialien und Energie, Macromolecular Crystallography, Albert-Einstein-Straße 15, D-12489, Berlin, Germany.
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227
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Marchant J, Bax A, Summers MF. Accurate Measurement of Residual Dipolar Couplings in Large RNAs by Variable Flip Angle NMR. J Am Chem Soc 2018; 140:6978-6983. [PMID: 29757635 PMCID: PMC6021016 DOI: 10.1021/jacs.8b03298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
NMR approaches using nucleotide-specific deuterium labeling schemes have enabled structural studies of biologically relevant RNAs of increasing size and complexity. Although local structure is well-determined using these methods, definition of global structural features, including relative orientations of independent helices, remains a challenge. Residual dipolar couplings, a potential source of orientation information, have not been obtainable for large RNAs due to poor sensitivity resulting from rapid heteronuclear signal decay. Here we report a novel multiple quantum NMR method for RDC determination that employs flip angle variation rather than a coupling evolution period. The accuracy of the method and its utility for establishing interhelical orientations are demonstrated for a 36-nucleotide RNA, for which comparative data could be obtained. Applied to a 78 kDa Rev response element from the HIV-1 virus, which has an effective rotational correlation time of ca. 160 ns, the method yields sensitivity gains of an order of magnitude or greater over existing approaches. Solution-state access to structural organization in RNAs of at least 230 nucleotides is now possible.
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Affiliation(s)
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes, Digestive and Kidney Diseases , National Institutes of Health , Bethesda , Maryland 20892 , United States
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228
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Mu X, Greenwald E, Ahmad S, Hur S. An origin of the immunogenicity of in vitro transcribed RNA. Nucleic Acids Res 2018; 46:5239-5249. [PMID: 29534222 PMCID: PMC6007322 DOI: 10.1093/nar/gky177] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/12/2018] [Accepted: 02/28/2018] [Indexed: 12/24/2022] Open
Abstract
The emergence of RNA-based therapeutics demands robust and economical methods to produce RNA with few byproducts from aberrant activity. While in vitro transcription using the bacteriophage T7 RNA polymerase is one such popular method, its transcripts are known to display an immune-stimulatory activity that is often undesirable and uncontrollable. We here showed that the immune-stimulatory activity of T7 transcript is contributed by its aberrant activity to initiate transcription from a promoter-less DNA end. This activity results in the production of an antisense RNA that is fully complementary to the intended sense RNA product, and consequently a long double-stranded RNA (dsRNA) that can robustly stimulate a cytosolic pattern recognition receptor, MDA5. This promoter-independent transcriptional activity of the T7 RNA polymerase was observed for a wide range of DNA sequences and lengths, but can be suppressed by altering the transcription reaction with modified nucleotides or by reducing the Mg2+ concentration. The current work thus not only offers a previously unappreciated mechanism by which T7 transcripts stimulate the innate immune system, but also shows that the immune-stimulatory activity can be readily regulated.
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MESH Headings
- DEAD Box Protein 58/genetics
- DEAD Box Protein 58/immunology
- DNA-Directed RNA Polymerases/genetics
- DNA-Directed RNA Polymerases/metabolism
- HEK293 Cells
- Humans
- Immunity, Innate/physiology
- Interferon-Induced Helicase, IFIH1/genetics
- Interferon-Induced Helicase, IFIH1/immunology
- Interferon-Induced Helicase, IFIH1/metabolism
- Interferon-beta/genetics
- Magnesium/pharmacology
- Nucleotides/genetics
- Nucleotides/metabolism
- Promoter Regions, Genetic
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/immunology
- RNA, Double-Stranded/metabolism
- Receptors, Immunologic
- Transcription, Genetic/drug effects
- Viral Proteins/genetics
- Viral Proteins/metabolism
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Affiliation(s)
- Xin Mu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Emily Greenwald
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Sadeem Ahmad
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
| | - Sun Hur
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, MA 02115, USA
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229
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Identification of the RNA Pseudoknot within the 3' End of the Porcine Reproductive and Respiratory Syndrome Virus Genome as a Pathogen-Associated Molecular Pattern To Activate Antiviral Signaling via RIG-I and Toll-Like Receptor 3. J Virol 2018; 92:JVI.00097-18. [PMID: 29618647 DOI: 10.1128/jvi.00097-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 03/28/2018] [Indexed: 12/24/2022] Open
Abstract
Once infected by viruses, cells can detect pathogen-associated molecular patterns (PAMPs) on viral nucleic acid by host pattern recognition receptors (PRRs) to initiate the antiviral response. Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of porcine reproductive and respiratory syndrome (PRRS), characterized by reproductive failure in sows and respiratory diseases in pigs of different ages. To date, the sensing mechanism of PRRSV has not been elucidated. Here, we reported that the pseudoknot region residing in the 3' untranslated regions (UTR) of the PRRSV genome, which has been proposed to regulate RNA synthesis and virus replication, was sensed as nonself by retinoic acid-inducible gene I (RIG-I) and Toll-like receptor 3 (TLR3) and strongly induced type I interferons (IFNs) and interferon-stimulated genes (ISGs) in porcine alveolar macrophages (PAMs). The interaction between the two stem-loops inside the pseudoknot structure was sufficient for IFN induction, since disruption of the pseudoknot interaction powerfully dampened the IFN induction. Furthermore, transfection of the 3' UTR pseudoknot transcripts in PAMs inhibited PRRSV replication in vitro Importantly, the predicted similar structures of other arterivirus members, including equine arteritis virus (EAV), lactate dehydrogenase-elevating virus (LDV), and simian hemorrhagic fever virus (SHFV), also displayed strong IFN induction activities. Together, in this work we identified an innate recognition mechanism by which the PRRSV 3' UTR pseudoknot region served as PAMPs of arteriviruses and activated innate immune signaling to produce IFNs that inhibit virus replication. All of these results provide novel insights into innate immune recognition during virus infection.IMPORTANCE PRRS is the most common viral disease in the pork industry. It is caused by PRRSV, a positive single-stranded RNA virus, whose infection often leads to persistent infection. To date, it is not yet clear how PRRSV is recognized by the host and what is the exact mechanism of IFN induction. Here, we investigated the nature of PAMPs on PRRSV and the associated PRRs. We found that the 3' UTR pseudoknot region of PRRSV, which has been proposed to regulate viral RNA synthesis, could act as PAMPs recognized by RIG-I and TLR3 to induce type I IFN production to suppress PRRSV infection. This report is the first detailed description of pattern recognition for PRRSV, which is important in understanding the antiviral response of arteriviruses, especially PRRSV, and extends our knowledge on virus recognition.
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230
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Grzela R, Nasilowska K, Lukaszewicz M, Tyras M, Stepinski J, Jankowska-Anyszka M, Bojarska E, Darzynkiewicz E. Hydrolytic activity of human Nudt16 enzyme on dinucleotide cap analogs and short capped oligonucleotides. RNA (NEW YORK, N.Y.) 2018; 24:633-642. [PMID: 29483298 PMCID: PMC5900562 DOI: 10.1261/rna.065698.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/20/2018] [Indexed: 05/30/2023]
Abstract
Human Nudt16 (hNudt16) is a member of the Nudix family of hydrolases, comprising enzymes catabolizing various substrates including canonical (d)NTPs, oxidized (d)NTPs, nonnucleoside polyphosphates, and capped mRNAs. Decapping activity of the Xenopus laevis (X29) Nudt16 homolog was observed in the nucleolus, with a high specificity toward U8 snoRNA. Subsequent studies have reported cytoplasmic localization of mammalian Nudt16 with cap hydrolysis activity initiating RNA turnover, similar to Dcp2. The present study focuses on hNudt16 and its hydrolytic activity toward dinucleotide cap analogs and short capped oligonucleotides. We performed a screening assay for potential dinucleotide and oligonucleotide substrates for hNudt16. Our data indicate that dinucleotide cap analogs and capped oligonucleotides containing guanine base in the first transcribed nucleotide are more susceptible to enzymatic digestion by hNudt16 than their counterparts containing adenine. Furthermore, unmethylated dinucleotides (GpppG and ApppG) and respective oligonucleotides (GpppG-16nt and GpppA-16nt) were hydrolyzed by hNudt16 with greater efficiency than were m7GpppG and m7GpppG-16nt. In conclusion, we found that hNudt16 hydrolysis of dinucleotide cap analogs and short capped oligonucleotides displayed a broader spectrum specificity than is currently known.
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Affiliation(s)
- Renata Grzela
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Karolina Nasilowska
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-097 Warsaw, Poland
| | - Maciej Lukaszewicz
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-097 Warsaw, Poland
| | - Michal Tyras
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Janusz Stepinski
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | | | - Elzbieta Bojarska
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
| | - Edward Darzynkiewicz
- Centre of New Technologies, University of Warsaw, 02-097 Warsaw, Poland
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-097 Warsaw, Poland
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231
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Design and Preparation of Aptamer-siRNA Chimeras (AsiCs) for Targeted Cancer Therapy. Methods Mol Biol 2018; 1632:175-186. [PMID: 28730439 DOI: 10.1007/978-1-4939-7138-1_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Conjugation of cell-internalizing DNA or RNA aptamers to tumor-suppressing siRNAs represents a novel promising approach for cancer therapy. Here we describe how to employ RNA aptamers that bind to cell surface receptors as carriers for cell-targeted siRNA (or miRNA) delivery. This protocol was optimized to improve the efficiency of the aptamer-siRNA/miRNA conjugates and facilitate its implementation in most molecular biology labs. The single working steps include (1) outlining the optimal sequences of the RNA strands bearing the aptamer and siRNA sequence, for which further (2) a dsDNA template is synthesized and then (3) transcribed into an RNA that will be (4) folded and annealed to a chemically synthesized siRNA complementary strand. Moreover, we reference recent examples and advances in the aptamer delivery field.
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232
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Liu Y, Chia ZH, Liew JNMH, Or SM, Phua KKL. Modulation of mRNA Translation and Cell Viability by Influenza A Virus Derived Nonstructural Protein 1. Nucleic Acid Ther 2018; 28:200-208. [PMID: 29634401 DOI: 10.1089/nat.2017.0712] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Translation of in vitro transcribed messenger RNA (mRNA) is known to be compromised by cell's innate immune responses. Herein we show that when mRNA encoding nonstructural protein 1 (NS1), an immune evasion gene derived from influenza A virus, is co-delivered with mRNA encoding green fluorescent protein (GFP), higher GFP expression can be observed in four different interferon competent cell types within 6 h, indicating NS1's wide host range property and rapid counter response to the cells' innate immune response. Enhanced mRNA translation correlates with reduced interferon production in all tested cell types and substituting a small portion of luciferase mRNA with NS1 mRNA enhances luciferase production compared to the same dose composing of only luciferase mRNA although in a cell type specific manner. Toxicity caused by transfection of unmodified mRNA is mitigated with the delivery of NS1 mRNA and is observed only in NS1 without cleavage and polyadenylation specificity factor 30 kda (CPSF30) inhibition function. Conversely, delivery of mRNA encoding NS1 with CPSF30 inhibition function aggravated toxicity. Overall, we demonstrate that NS1 enhanced mRNA transfection through active evasion of innate immune responses and modulated cellular viability during mRNA transfection.
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Affiliation(s)
- Yi Liu
- Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore , Singapore, Singapore
| | - Zhen Hua Chia
- Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore , Singapore, Singapore
| | - Johannes Nathaniel Min Hui Liew
- Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore , Singapore, Singapore
| | - Shi Min Or
- Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore , Singapore, Singapore
| | - Kyle K L Phua
- Department of Chemical and Biomolecular Engineering, Faculty of Engineering, National University of Singapore , Singapore, Singapore
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233
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Chan CW, Kiesel BR, Mondragón A. Crystal Structure of Human Rpp20/Rpp25 Reveals Quaternary Level Adaptation of the Alba Scaffold as Structural Basis for Single-stranded RNA Binding. J Mol Biol 2018; 430:1403-1416. [PMID: 29625199 DOI: 10.1016/j.jmb.2018.03.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 03/21/2018] [Accepted: 03/25/2018] [Indexed: 11/25/2022]
Abstract
Ribonuclease P (RNase P) catalyzes the removal of 5' leaders of tRNA precursors and its central catalytic RNA subunit is highly conserved across all domains of life. In eukaryotes, RNase P and RNase MRP, a closely related ribonucleoprotein enzyme, share several of the same protein subunits, contain a similar catalytic RNA core, and exhibit structural features that do not exist in their bacterial or archaeal counterparts. A unique feature of eukaryotic RNase P/MRP is the presence of two relatively long and unpaired internal loops within the P3 region of their RNA subunit bound by a heterodimeric protein complex, Rpp20/Rpp25. Here we present a crystal structure of the human Rpp20/Rpp25 heterodimer and we propose, using comparative structural analyses, that the evolutionary divergence of the single-stranded and helical nucleic acid binding specificities of eukaryotic Rpp20/Rpp25 and their related archaeal Alba chromatin protein dimers, respectively, originate primarily from quaternary level differences observed in their heterodimerization interface. Our work provides structural insights into how the archaeal Alba protein scaffold was adapted evolutionarily for incorporation into several functionally-independent eukaryotic ribonucleoprotein complexes.
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Affiliation(s)
- Clarence W Chan
- Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Evanston, IL 60208-3500, United States
| | - Benjamin R Kiesel
- Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Evanston, IL 60208-3500, United States
| | - Alfonso Mondragón
- Department of Molecular Biosciences, Northwestern University, 2205 Tech Drive, Evanston, IL 60208-3500, United States.
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234
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Hopkins PA, McCoy LS, Tor Y. Enzymatic incorporation and utilization of an emissive 6-azauridine. Org Biomol Chem 2018; 15:684-690. [PMID: 27981333 DOI: 10.1039/c6ob02080a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
To display favorable fluorescent properties, the non-emissive native nucleosides need to be modified. Here we present a motif that relies on conjugating 5-membered aromatic heterocycles (e.g., thiophene) to a 6-azapyrimidine (1,2,4-triazine) core. Synthetic accessibility and desirable photophysical properties make these nucleosides attractive candidates for enzymatic incorporation and biochemical assays. While 6-azauridine triphosphate is known to be poorly tolerated by polymerases in RNA synthesis, we illustrate that conjugating a thiophene ring at position 5 overcomes such limitations, facilitating its T7 RNA polymerase-mediated in vitro transcription incorporation into RNA constructs. We further show that the modified transcripts can be ligated to longer oligonucleotides to form singly modified RNAs, as illustrated for an A-site hairpin model RNA construct, which was employed to visualize aminoglycoside antibiotics binding.
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Affiliation(s)
- Patrycja A Hopkins
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
| | - Lisa S McCoy
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
| | - Yitzhak Tor
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
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235
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Guo S, Piao X, Li H, Guo P. Methods for construction and characterization of simple or special multifunctional RNA nanoparticles based on the 3WJ of phi29 DNA packaging motor. Methods 2018. [PMID: 29530505 DOI: 10.1016/j.ymeth.2018.02.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The field of RNA nanotechnology has developed rapidly over the last decade, as more elaborate RNA nanoarchitectures and therapeutic RNA nanoparticles have been constructed, and their applications have been extensively explored. Now it is time to offer different levels of RNA construction methods for both the beginners and the experienced researchers or enterprisers. The first and second parts of this article will provide instructions on basic and simple methods for the assembly and characterization of RNA nanoparticles, mainly based on the pRNA three-way junction (pRNA-3WJ) of phi29 DNA packaging motor. The third part of this article will focus on specific methods for the construction of more sophisticated multivalent RNA nanoparticles for therapeutic applications. In these parts, some simple protocols are provided to facilitate the initiation of the RNA nanoparticle construction in labs new to the field of RNA nanotechnology. This article is intended to serve as a general reference aimed at both apprentices and senior scientists for their future design, construction and characterization of RNA nanoparticles based on the pRNA-3WJ of phi29 DNA packaging motor.
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Affiliation(s)
- Sijin Guo
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH 43210, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Xijun Piao
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH 43210, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Hui Li
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH 43210, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH 43210, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH 43210, USA; College of Medicine, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA; James Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA.
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236
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Mao G, Srivastava AS, Wu S, Kosek D, Lindell M, Kirsebom LA. Critical domain interactions for type A RNase P RNA catalysis with and without the specificity domain. PLoS One 2018; 13:e0192873. [PMID: 29509761 PMCID: PMC5839562 DOI: 10.1371/journal.pone.0192873] [Citation(s) in RCA: 4] [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: 12/08/2017] [Accepted: 01/18/2018] [Indexed: 12/17/2022] Open
Abstract
The natural trans-acting ribozyme RNase P RNA (RPR) is composed of two domains in which the catalytic (C-) domain mediates cleavage of various substrates. The C-domain alone, after removal of the second specificity (S-) domain, catalyzes this reaction as well, albeit with reduced efficiency. Here we provide experimental evidence indicating that efficient cleavage mediated by the Escherichia coli C-domain (Eco CP RPR) with and without the C5 protein likely depends on an interaction referred to as the "P6-mimic". Moreover, the P18 helix connects the C- and S-domains between its loop and the P8 helix in the S-domain (the P8/ P18-interaction). In contrast to the "P6-mimic", the presence of P18 does not contribute to the catalytic performance by the C-domain lacking the S-domain in cleavage of an all ribo model hairpin loop substrate while deletion or disruption of the P8/ P18-interaction in full-size RPR lowers the catalytic efficiency in cleavage of the same model hairpin loop substrate in keeping with previously reported data using precursor tRNAs. Consistent with that P18 is not required for cleavage mediated by the C-domain we show that the archaeal Pyrococcus furiosus RPR C-domain, which lacks the P18 helix, is catalytically active in trans without the S-domain and any protein. Our data also suggest that the S-domain has a larger impact on catalysis for E. coli RPR compared to P. furiosus RPR. Finally, we provide data indicating that the absence of the S-domain and P18, or the P8/ P18-interaction in full-length RPR influences the charge distribution near the cleavage site in the RPR-substrate complex to a small but reproducible extent.
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Affiliation(s)
- Guanzhong Mao
- Department of Cell and Molecular Biology, Biomedical Centre, Uppsala, Sweden
| | - Abhishek S. Srivastava
- Department of Cell and Molecular Biology, Biomedical Centre, Uppsala, Sweden
- Discovery Sciences, AstraZeneca R&D, Cambridge Science Park, Cambridge, United Kingdom
| | - Shiying Wu
- Department of Cell and Molecular Biology, Biomedical Centre, Uppsala, Sweden
| | - David Kosek
- Department of Cell and Molecular Biology, Biomedical Centre, Uppsala, Sweden
| | - Magnus Lindell
- Department of Cell and Molecular Biology, Biomedical Centre, Uppsala, Sweden
| | - Leif A. Kirsebom
- Department of Cell and Molecular Biology, Biomedical Centre, Uppsala, Sweden
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237
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Masaki Y, Ito H, Oda Y, Yamazaki K, Tago N, Ohno K, Ishii N, Tsunoda H, Kanamori T, Ohkubo A, Sekine M, Seio K. Enzymatic synthesis and reverse transcription of RNAs incorporating 2'-O-carbamoyl uridine triphosphate. Chem Commun (Camb) 2018; 52:12889-12892. [PMID: 27738673 DOI: 10.1039/c6cc05796a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Enzymatic synthesis and the reverse transcription of RNAs containing 2'-O-carbamoyl uridine were evaluated. A mild acidic deprotection procedure allowed the synthesis of 2'-O-carbamoyl uridine triphosphate (UcmTP). UcmTP was incorporated correctly into long RNAs, and its fidelity during reverse transcription using SuperScript III was sufficient for RNA aptamer selection.
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Affiliation(s)
- Yoshiaki Masaki
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Hyugo Ito
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Yuki Oda
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Kazufumi Yamazaki
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Nobuhiro Tago
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Kentaro Ohno
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Nozomi Ishii
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Hirosuke Tsunoda
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Takashi Kanamori
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Akihiro Ohkubo
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Mitsuo Sekine
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
| | - Kohji Seio
- Department of Life Science and Technology, Tokyo Institute of Technology, J2-16, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan.
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238
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Yang Y, Wang S. RNA Characterization by Solid-State NMR Spectroscopy. Chemistry 2018; 24:8698-8707. [DOI: 10.1002/chem.201705583] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Indexed: 02/05/2023]
Affiliation(s)
- Yufei Yang
- College of Chemistry and Molecular Engineering and Beijing NMR Center; Peking University; No.5 Yiheyuan Road, Haidian District Beijing 100871 P. R. China
| | - Shenlin Wang
- College of Chemistry and Molecular Engineering and Beijing NMR Center; Peking University; No.5 Yiheyuan Road, Haidian District Beijing 100871 P. R. China
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239
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Chu CC, Silverman SK. Assessing histidine tags for recruiting deoxyribozymes to catalyze peptide and protein modification reactions. Org Biomol Chem 2018; 14:4697-703. [PMID: 27138704 DOI: 10.1039/c6ob00716c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We evaluate the ability of hexahistidine (His6) tags on peptide and protein substrates to recruit deoxyribozymes for modifying those substrates. For two different deoxyribozymes, one that creates tyrosine-RNA nucleopeptides and another that phosphorylates tyrosine side chains, we find substantial improvements in yield, kobs, and Km for peptide substrates due to recruiting by His6/Cu(2+). However, the recruiting benefits of the histidine tag are not observed for larger protein substrates, likely because the tested deoxyribozymes either cannot access the target peptide segments or cannot function when these segments are presented in a structured protein context.
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Affiliation(s)
- Chih-Chi Chu
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
| | - Scott K Silverman
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
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240
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Artificial Division of Codon Boxes for Expansion of the Amino Acid Repertoire of Ribosomal Polypeptide Synthesis. Methods Mol Biol 2018; 1728:17-47. [PMID: 29404989 DOI: 10.1007/978-1-4939-7574-7_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In ribosomal polypeptide synthesis, the 61 sense codons redundantly code for the 20 proteinogenic amino acids. The genetic code contains eight family codon boxes consisting of synonymous codons that redundantly code for the same amino acid. Here, we describe the protocol of a recently published method to artificially divide such family codon boxes and encode multiple nonproteinogenic amino acids in addition to the 20 proteinogenic ones in a reprogrammed genetic code. To achieve this, an in vitro translation system reconstituted with 32 in vitro transcribed tRNASNN's (S = C or G; N = U, C, A or G) was first developed, where the 32 tRNA transcripts can be charged with 20 proteinogenic amino acids by aminoacyl-tRNA synthetases in situ and orthogonally decode the corresponding 31 NNS sense codons as well as the AUG initiation codon. When some redundant tRNAGNN's are replaced with tRNAGNN's precharged with nonproteinogenic amino acids by means of flexizymes, the nonproteinogenic and proteinogenic aminoacyl-tRNAs can decode the NNC and NNG codons in the same family codon box independently. In this protocol, we describe expression of model peptides, including a macrocyclic peptide containing three kinds of N-methyl-amino acids reassigned to the vacant codons generated by the method of artificial division of codon boxes.
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241
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Fang PY, Bowman JC, Gómez Ramos L, Hsiao C, Williams LD. RNA: packaged and protected by VLPs. RSC Adv 2018; 8:21399-21406. [PMID: 35539947 PMCID: PMC9080931 DOI: 10.1039/c8ra02084a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/04/2018] [Indexed: 01/16/2023] Open
Abstract
VLP packaging is most efficient for compact RNA, and protects RNA against assault by small diffusible damaging agents.
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Affiliation(s)
- Po-Yu Fang
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
| | - Jessica C. Bowman
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
| | - Lizzette M. Gómez Ramos
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
- School of Chemical and Biomolecular Engineering
| | - Chiaolong Hsiao
- Institute of Biochemical Sciences
- National Taiwan University
- Taipei 10617
- Republic of China
| | - Loren Dean Williams
- School of Chemistry and Biochemistry
- Georgia Institute of Technology
- Atlanta
- USA
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242
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Lyon S, Gopalan V. A T7 RNA Polymerase Mutant Enhances the Yield of 5'-Thienoguanosine-Initiated RNAs. Chembiochem 2017; 19:142-146. [PMID: 29115013 DOI: 10.1002/cbic.201700538] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Indexed: 12/19/2022]
Abstract
Spectroscopic methods, which are used to establish RNA structure-function relationships, require strategies for post-synthetic, site-specific incorporation of chemical probes into target RNAs. For RNAs larger than 50 nt, the enzymatic incorporation of a nucleoside or nucleotide monophosphate guanosine analogue (G analogue) at their 5'-end is routinely achieved by T7 RNA polymerase (T7RNAP)-mediated in vitro transcription (IVT) of the appropriate DNA template containing a GTP-initiating class III Φ6.5 promoter. However, when high G analogue:GTP ratios are used to bias G analogue incorporation at the 5'-end, RNA yield is compromised. Here, we show that the use of a T7RNAP P266L mutant in IVT with 10:1 thienoguanosine (th G):GTP increased the percent incorporation and yield of 5'-th G-initiated precursor tRNA for a net ≈threefold gain compared to IVT with wild-type T7RNAP. We also demonstrated that a one-pot multienzyme approach, consisting of transcription by T7RNAP P266L and post-transcriptional cleanup by polyphosphatase and an exonuclease, led to essentially near-homogeneous 5'-th G-modified transcripts. This approach should be of broad utility in preparing 5'-modified RNAs.
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Affiliation(s)
- Seth Lyon
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, 484 West 12th Avenue, Columbus, OH, 43210, USA
| | - Venkat Gopalan
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, 484 West 12th Avenue, Columbus, OH, 43210, USA
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243
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Comandur R, Olson ED, Musier-Forsyth K. Conservation of tRNA mimicry in the 5'-untranslated region of distinct HIV-1 subtypes. RNA (NEW YORK, N.Y.) 2017; 23:1850-1859. [PMID: 28860303 PMCID: PMC5689005 DOI: 10.1261/rna.062182.117] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/25/2017] [Indexed: 06/07/2023]
Abstract
Human tRNALys3 serves as the primer for reverse transcription in human immunodeficiency virus type-1 (HIV-1) and anneals to the complementary primer binding site (PBS) in the genome. All tRNALys isoacceptors interact with human lysyl-tRNA synthetase (hLysRS) and are selectively packaged into virions. tRNALys3 must be released from hLysRS in order to anneal to the PBS, and this process is proposed to be facilitated by the interaction of hLysRS with a tRNA-like element (TLE) first identified in the HIV-1 5'-untranslated region (5'-UTR) of the subtype B NL4-3 virus. However, a significant subset of HIV-1 strains represented by the MAL isolate possess a different secondary structure in this region of the genome. Thus, to establish the conservation of this mechanism for primer targeting and release, we investigated the subtype A-like 5'-UTR of the MAL isolate. hLysRS bound to a 229-nt MAL RNA containing the PBS domain with high affinity (Kd = 47 nM), and to a 98-nt truncated construct with ∼10-fold reduced affinity. These results resemble previous studies using analogous NL4-3-derived RNAs. However, in contrast to studies with NL4-3, no binding was observed to smaller stem-loop elements within the MAL PBS domain. The tertiary structure of the 98-nt construct was analyzed using small-angle X-ray scattering, revealing remarkable global structural similarity to the corresponding NL4-3 PBS/TLE region. These results suggest that the tRNA-like structure within the 5'-UTR is conserved across distinct HIV-1 subtypes and that hLysRS recognition of the MAL isolate is likely not conferred by specific sequence elements but by 3D structure.
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Affiliation(s)
- Roopa Comandur
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Erik D Olson
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Karin Musier-Forsyth
- Department of Chemistry and Biochemistry, Center for Retrovirus Research and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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244
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Huang Z, Wen W, Wu A, Niu L. Chemically Modified, α-Amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) Receptor RNA Aptamers Designed for in Vivo Use. ACS Chem Neurosci 2017; 8:2437-2445. [PMID: 28872832 DOI: 10.1021/acschemneuro.7b00211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Glutamate ion channels have three subtypes, that is, α-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA), kainate, and N-methyl-d-aspartate (NMDA) receptors. Excessive activity of these receptor subtypes either individually or collectively is involved in various neurological disorders. RNA aptamers as antagonists of these receptors are potential therapeutics. For developing aptamer therapeutics, the RNA aptamers must be chemically modified to become ribonuclease-resistant or stable in biological fluids. Using systematic evolution of ligands by exponential enrichment (SELEX) and a chemically modified library, prepared enzymatically (i.e., the library contains RNAs with 2'-fluoro modified nucleoside triphosphates or ATPs, CTPs and UTPs, but regular GTPs), we have isolated an aptamer. The short aptamer (69 nucleotides) FN1040s selectively inhibits the GluA1 and GluA2Qflip AMPA receptor subunits, whereas the full-length aptamer (101 nucleotides) FN1040 additionally inhibits GluK1, but not GluK2, kainate receptor, and GluN1a/2A and GluN1a/2B, the two major native NMDA receptors. The two aptamers show similar potency (2-4 μM) and are stable with a half-life of at least 2 days in serum-containing medium or cerebrospinal fluid. Therefore, these two aptamers are amenable for in vivo use.
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Affiliation(s)
- Zhen Huang
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222, United States
| | - Wei Wen
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222, United States
| | - Andrew Wu
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222, United States
| | - Li Niu
- Department of Chemistry and
Center for Neuroscience Research, University at Albany, SUNY, Albany, New York 12222, United States
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245
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Saramago M, Peregrina A, Robledo M, Matos RG, Hilker R, Serrania J, Becker A, Arraiano CM, Jiménez-Zurdo JI. Sinorhizobium meliloti YbeY is an endoribonuclease with unprecedented catalytic features, acting as silencing enzyme in riboregulation. Nucleic Acids Res 2017; 45:1371-1391. [PMID: 28180335 PMCID: PMC5388416 DOI: 10.1093/nar/gkw1234] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 11/22/2016] [Accepted: 11/24/2016] [Indexed: 01/23/2023] Open
Abstract
Structural and biochemical features suggest that the almost ubiquitous bacterial YbeY protein may serve catalytic and/or Hfq-like protective functions central to small RNA (sRNA)-mediated regulation and RNA metabolism. We have biochemically and genetically characterized the YbeY ortholog of the legume symbiont Sinorhizobium meliloti (SmYbeY). Co-immunoprecipitation (CoIP) with a FLAG-tagged SmYbeY yielded a poor enrichment in RNA species, compared to Hfq CoIP-RNA uncovered previously by a similar experimental setup. Purified SmYbeY behaved as a monomer that indistinctly cleaved single- and double-stranded RNA substrates, a unique ability among bacterial endoribonucleases. SmYbeY-mediated catalysis was supported by the divalent metal ions Mg2+, Mn2+ and Ca2+, which influenced in a different manner cleavage efficiency and reactivity patterns, with Ca2+ specifically blocking activity on double-stranded and some structured RNA molecules. SmYbeY loss-of-function compromised expression of core energy and RNA metabolism genes, whilst promoting accumulation of motility, late symbiotic and transport mRNAs. Some of the latter transcripts are known Hfq-binding sRNA targets and might be SmYbeY substrates. Genetic reporter and in vitro assays confirmed that SmYbeY is required for sRNA-mediated down-regulation of the amino acid ABC transporter prbA mRNA. We have thus discovered a bacterial endoribonuclease with unprecedented catalytic features, acting also as gene silencing enzyme.
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Affiliation(s)
- Margarida Saramago
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
- These authors contributed equally to the work as the first authors
| | - Alexandra Peregrina
- Grupo de Ecología Genética de la Rizosfera, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), 18008 Granada, Spain
- These authors contributed equally to the work as the first authors
| | - Marta Robledo
- Grupo de Ecología Genética de la Rizosfera, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), 18008 Granada, Spain
- These authors contributed equally to the work as the first authors
| | - Rute G. Matos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
| | - Rolf Hilker
- LOEWE Center for Synthetic Microbiology and Faculty of Biology, Philipps-University Marburg, 35043 Marburg, Germany
| | - Javier Serrania
- LOEWE Center for Synthetic Microbiology and Faculty of Biology, Philipps-University Marburg, 35043 Marburg, Germany
| | - Anke Becker
- LOEWE Center for Synthetic Microbiology and Faculty of Biology, Philipps-University Marburg, 35043 Marburg, Germany
| | - Cecilia M. Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República, 2780-157 Oeiras, Portugal
| | - José I. Jiménez-Zurdo
- Grupo de Ecología Genética de la Rizosfera, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), 18008 Granada, Spain
- To whom correspondence should be addressed. Tel: +34 958181600; Fax: +34 958181609;
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246
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HIV-1 Exploits a Dynamic Multi-aminoacyl-tRNA Synthetase Complex To Enhance Viral Replication. J Virol 2017; 91:JVI.01240-17. [PMID: 28814526 DOI: 10.1128/jvi.01240-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 08/10/2017] [Indexed: 11/20/2022] Open
Abstract
A hallmark of retroviruses such as human immunodeficiency virus type 1 (HIV-1) is reverse transcription of genomic RNA to DNA, a process that is primed by cellular tRNAs. HIV-1 recruits human tRNALys3 to serve as the reverse transcription primer via an interaction between lysyl-tRNA synthetase (LysRS) and the HIV-1 Gag polyprotein. LysRS is normally sequestered in a multi-aminoacyl-tRNA synthetase complex (MSC). Previous studies demonstrated that components of the MSC can be mobilized in response to certain cellular stimuli, but how LysRS is redirected from the MSC to viral particles for packaging is unknown. Here, we show that upon HIV-1 infection, a free pool of non-MSC-associated LysRS is observed and partially relocalized to the nucleus. Heat inactivation of HIV-1 blocks nuclear localization of LysRS, but treatment with a reverse transcriptase inhibitor does not, suggesting that the trigger for relocalization occurs prior to reverse transcription. A reduction in HIV-1 infection is observed upon treatment with an inhibitor to mitogen-activated protein kinase that prevents phosphorylation of LysRS on Ser207, release of LysRS from the MSC, and nuclear localization. A phosphomimetic mutant of LysRS (S207D) that lacked the capability to aminoacylate tRNALys3 localized to the nucleus, rescued HIV-1 infectivity, and was packaged into virions. In contrast, a phosphoablative mutant (S207A) remained cytosolic and maintained full aminoacylation activity but failed to rescue infectivity and was not packaged. These findings suggest that HIV-1 takes advantage of the dynamic nature of the MSC to redirect and coopt cellular translation factors to enhance viral replication.IMPORTANCE Human tRNALys3, the primer for reverse transcription, and LysRS are essential host factors packaged into HIV-1 virions. Previous studies found that tRNALys3 packaging depends on interactions between LysRS and HIV-1 Gag; however, many details regarding the mechanism of tRNALys3 and LysRS packaging remain unknown. LysRS is normally sequestered in a high-molecular-weight multi-aminoacyl-tRNA synthetase complex (MSC), restricting the pool of free LysRS-tRNALys Mounting evidence suggests that LysRS is released under a variety of stimuli to perform alternative functions within the cell. Here, we show that HIV-1 infection results in a free pool of LysRS that is relocalized to the nucleus of target cells. Blocking this pathway in HIV-1-producing cells resulted in less infectious progeny virions. Understanding the mechanism by which LysRS is recruited into the viral assembly pathway can be exploited for the development of specific and effective therapeutics targeting this nontranslational function.
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247
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Dussault AM, Dubé A, Jacques F, Grondin JP, Lafontaine DA. Ligand recognition and helical stacking formation are intimately linked in the SAM-I riboswitch regulatory mechanism. RNA (NEW YORK, N.Y.) 2017; 23:1539-1551. [PMID: 28701520 PMCID: PMC5602112 DOI: 10.1261/rna.061796.117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
Riboswitches are noncoding mRNA elements that control gene expression by altering their structure upon metabolite binding. Although riboswitch crystal structures provide detailed information about RNA-ligand interactions, little knowledge has been gathered to understand how riboswitches modulate gene expression. Here, we study the molecular recognition mechanism of the S-adenosylmethionine SAM-I riboswitch by characterizing the formation of a helical stacking interaction involving the ligand-binding process. We show that ligand binding is intimately linked to the formation of the helical stacking, which is dependent on the presence of three conserved purine residues that are flanked by stacked helices. We also find that these residues are important for the formation of a crucial long-range base pair formed upon SAM binding. Together, our results lend strong support to a critical role for helical stacking in the folding pathway and suggest a particularly important function in the formation of the long-range base pair.
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Affiliation(s)
- Anne-Marie Dussault
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Audrey Dubé
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Frédéric Jacques
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Jonathan P Grondin
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Daniel A Lafontaine
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
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248
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Chen T, Romesberg FE. A Method for the Exponential Synthesis of RNA: Introducing the Polymerase Chain Transcription (PCT) Reaction. Biochemistry 2017; 56:5227-5228. [DOI: 10.1021/acs.biochem.7b00846] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tingjian Chen
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Floyd E. Romesberg
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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249
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LeBlanc RM, Longhini AP, Le Grice SF, Johnson BA, Dayie TK. Combining asymmetric 13C-labeling and isotopic filter/edit NOESY: a novel strategy for rapid and logical RNA resonance assignment. Nucleic Acids Res 2017; 45:e146. [PMID: 28934505 PMCID: PMC5766159 DOI: 10.1093/nar/gkx591] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Revised: 06/22/2017] [Accepted: 08/04/2017] [Indexed: 01/08/2023] Open
Abstract
Although ∼98% of the human genomic output is transcribed as non-protein coding RNA, <2% of the protein data bank structures comprise RNA. This huge structural disparity stems from combined difficulties of crystallizing RNA for X-ray crystallography along with extensive chemical shift overlap and broadened linewidths associated with NMR of RNA. While half of the deposited RNA structures in the PDB were solved by NMR methods, the usefulness of NMR is still limited by the high cost of sample preparation and challenges of resonance assignment. Here we propose a novel strategy for resonance assignment that combines new strategic 13C labeling technologies with filter/edit type NOESY experiments to greatly reduce spectral complexity and crowding. This new strategy allowed us to assign important non-exchangeable resonances of proton and carbon (1', 2', 2, 5, 6 and 8) nuclei using only one sample and <24 h of NMR instrument time for a 27 nt model RNA. The method was further extended to assigning a 6 nt bulge from a 61 nt viral RNA element justifying its use for a wide range RNA chemical shift resonance assignment problems.
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Affiliation(s)
- Regan M. LeBlanc
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
- Basic Research Laboratory, National Cancer Institute, Frederick, MD 21702, USA
| | - Andrew P. Longhini
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | | | - Bruce A. Johnson
- One Moon Scientific, Inc., Westfield, NJ 07090, USA
- Structural Biology Initiative, Advanced Science Research Center at the Graduate Center of the City University of New York, New York, NY 10031, USA
| | - Theodore K. Dayie
- Center for Biomolecular Structure and Organization, Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
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250
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Tolbert M, Morgan CE, Pollum M, Crespo-Hernández CE, Li ML, Brewer G, Tolbert BS. HnRNP A1 Alters the Structure of a Conserved Enterovirus IRES Domain to Stimulate Viral Translation. J Mol Biol 2017; 429:2841-2858. [PMID: 28625847 PMCID: PMC5610934 DOI: 10.1016/j.jmb.2017.06.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/08/2017] [Accepted: 06/08/2017] [Indexed: 01/25/2023]
Abstract
Enteroviruses use a type I Internal Ribosome Entry Site (IRES) structure to facilitate protein synthesis and promote genome replication. Type I IRES elements require auxiliary host proteins to organize RNA structure for 40S ribosomal subunit assembly. Heterogeneous nuclear ribonucleoprotein A1 stimulates enterovirus 71 (EV71) translation in part through specific interactions with its stem loop II (SLII) IRES domain. Here, we determined a conjoined NMR-small angle x-ray scattering structure of the EV71 SLII domain and a mutant that significantly attenuates viral replication by abrogating hnRNP A1 interactions. Native SLII adopts a locally compact structure wherein stacking interactions in a conserved 5'-AUAGC-3' bulge preorganize the adjacent helices at nearly orthogonal orientations. Mutating the bulge sequence to 5'-ACCCC-3' ablates base stacking in the loop and globally reorients the SLII structure. Biophysical titrations reveal that the 5'-AUAGC-3' bulge undergoes a conformational change to assemble a functional hnRNP A1-RNA complex. Importantly, IRES mutations that delete the bulge impair viral translation and completely inhibit replication. Thus, this work provides key details into how an EV71 IRES structure adapts to hijack a cellular protein, and it suggests that the SLII domain is a potential target for antiviral therapy.
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Affiliation(s)
- Michele Tolbert
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106-7078 USA
| | - Christopher E Morgan
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106-7078 USA
| | - Marvin Pollum
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106-7078 USA
| | | | - Mei-Ling Li
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, 08854 USA
| | - Gary Brewer
- Department of Biochemistry and Molecular Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, 08854 USA
| | - Blanton S Tolbert
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, 44106-7078 USA.
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