1
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Hoffmann A, Lorenz C, Fallmann J, Wolff P, Lechner A, Betat H, Mörl M, Stadler PF. Temperature-Dependent tRNA Modifications in Bacillales. Int J Mol Sci 2024; 25:8823. [PMID: 39201508 PMCID: PMC11354880 DOI: 10.3390/ijms25168823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Revised: 08/09/2024] [Accepted: 08/12/2024] [Indexed: 09/02/2024] Open
Abstract
Transfer RNA (tRNA) modifications are essential for the temperature adaptation of thermophilic and psychrophilic organisms as they control the rigidity and flexibility of transcripts. To further understand how specific tRNA modifications are adjusted to maintain functionality in response to temperature fluctuations, we investigated whether tRNA modifications represent an adaptation of bacteria to different growth temperatures (minimal, optimal, and maximal), focusing on closely related psychrophilic (P. halocryophilus and E. sibiricum), mesophilic (B. subtilis), and thermophilic (G. stearothermophilus) Bacillales. Utilizing an RNA sequencing approach combined with chemical pre-treatment of tRNA samples, we systematically profiled dihydrouridine (D), 4-thiouridine (s4U), 7-methyl-guanosine (m7G), and pseudouridine (Ψ) modifications at single-nucleotide resolution. Despite their close relationship, each bacterium exhibited a unique tRNA modification profile. Our findings revealed increased tRNA modifications in the thermophilic bacterium at its optimal growth temperature, particularly showing elevated levels of s4U8 and Ψ55 modifications compared to non-thermophilic bacteria, indicating a temperature-dependent regulation that may contribute to thermotolerance. Furthermore, we observed higher levels of D modifications in psychrophilic and mesophilic bacteria, indicating an adaptive strategy for cold environments by enhancing local flexibility in tRNAs. Our method demonstrated high effectiveness in identifying tRNA modifications compared to an established tool, highlighting its potential for precise tRNA profiling studies.
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Affiliation(s)
- Anne Hoffmann
- Helmholtz Institute for Metabolic, Obesity and Vascular Research, Helmholtz Zentrum München of the University of Leipzig and University Hospital Leipzig, Philipp-Rosenthal-Str. 27, D-04103 Leipzig, Germany;
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Härtelstraße 16–18, D-04107 Leipzig, Germany;
| | - Christian Lorenz
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, D-04103 Leipzig, Germany (H.B.); (M.M.)
| | - Jörg Fallmann
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Härtelstraße 16–18, D-04107 Leipzig, Germany;
| | - Philippe Wolff
- Architecture et Réactivité de l’ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, F-67084 Strasbourg, France; (P.W.); (A.L.)
| | - Antony Lechner
- Architecture et Réactivité de l’ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, F-67084 Strasbourg, France; (P.W.); (A.L.)
| | - Heike Betat
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, D-04103 Leipzig, Germany (H.B.); (M.M.)
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Brüderstraße 34, D-04103 Leipzig, Germany (H.B.); (M.M.)
| | - Peter F. Stadler
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Härtelstraße 16–18, D-04107 Leipzig, Germany;
- German Center for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Competence Center for Scalable Data Services and Solutions and Leipzig Research Center for Civilization Diseases, University Leipzig, Puschstrasse 4, D-04103 Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, D-04103 Leipzig, Germany
- Institute for Theoretical Chemistry, University of Vienna, Währingerstrasse 17, A-1090 Wien, Austria
- Facultad de Ciencias, Universidad National de Colombia, Bogotá CO-111321, Colombia
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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2
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Cao X, Tang L, Song J. Circular Single-Stranded DNA: Discovery, Biological Effects, and Applications. ACS Synth Biol 2024; 13:1038-1058. [PMID: 38501391 DOI: 10.1021/acssynbio.4c00040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
The field of nucleic acid therapeutics has witnessed a significant surge in recent times, as evidenced by the increasing number of approved genetic drugs. However, current platform technologies containing plasmids, lipid nanoparticle-mRNAs, and adeno-associated virus vectors encounter various limitations and challenges. Thus, we are devoted to finding a novel nucleic acid vector and have directed our efforts toward investigating circular single-stranded DNA (CssDNA), an ancient form of nucleic acid. CssDNAs are ubiquitous, but generally ignored. Accumulating evidence suggests that CssDNAs possess exceptional properties as nucleic acid vectors, exhibiting great potential for clinical applications in genetic disorders, gene editing, and immune cell therapy. Here, we comprehensively review the discovery and biological effects of CssDNAs as well as their applications in the field of biomedical research for the first time. Undoubtedly, as an ancient form of DNA, CssDNA holds immense potential and promises novel insights for biomedical research.
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Affiliation(s)
- Xisen Cao
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Linlin Tang
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou 310022, China
| | - Jie Song
- Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
- Hangzhou Institute of Medicine, Chinese Academy of Sciences, Hangzhou 310022, China
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3
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Ma Z, Chen H, Yang Y, Gao S, Yang J, Cui S, Zhou S, Jiang B, Zou B, Sun M, Wang L. Characterization of an ssDNA ligase and its application in aptamer circularization. Anal Biochem 2024; 685:115409. [PMID: 38006953 DOI: 10.1016/j.ab.2023.115409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/08/2023] [Accepted: 11/20/2023] [Indexed: 11/27/2023]
Abstract
Aptamers are widely used in various biomedical areas as novel molecular recognition elements, however, short single-stranded DNA (ssDNA) or RNA oligonucleotides are easily degraded by nucleases in biological fluids. This problem can be solved by circularizing aptamers with circular ligases. Herein, a moderately thermostable ssDNA ligase was expressed and purified. The purified ligase showed good circularization activity for different length substrates and much higher circularization efficiency than T4 RNA ligase 1. Biochemical characterization revealed that the enzyme showed optimal circularization activity at pH 7.5 and 50 ᵒC. Mn2+ and Mg2+ increased enzyme circularization activity, with Mn2+ having higher activity than Mg2+. The optimal concentrations of Mn2+ and ligase were 1.25-2.5 mM and 0.02 nM, respectively. The kinetic parameters Km, Vmax and Kcat of ssDNA ligase were 1.16 μM, 10.71 μM/min, and 10.7 min-1, respectively. The ssDNA ligase efficiency was nucleotide-dependent, and 5'-G and 3'-T were the most ligase-favored terminal nucleotides. In addition, the affinity and stability of the circular aptamer were determined. The affinity constant (KD) was 4.9 μM, and the stability increased compared to its linear form. Molecular docking results showed that the circular aptamer bound to the target via two hydrogen bonds. This study provides a simple and efficient aptamer circularization modification method for improving aptamer stability and expanding its applications.
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Affiliation(s)
- Zhenxia Ma
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Han Chen
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Yao Yang
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Siyi Gao
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Jiaping Yang
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Shihai Cui
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Shiyuan Zhou
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Boyang Jiang
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Bin Zou
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Mingjuan Sun
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China.
| | - Lianghua Wang
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China.
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4
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Kolberg T, von Löhneysen S, Ozerova I, Wellner K, Hartmann R, Stadler P, Mörl M. Led-Seq: ligation-enhanced double-end sequence-based structure analysis of RNA. Nucleic Acids Res 2023; 51:e63. [PMID: 37114986 PMCID: PMC10287922 DOI: 10.1093/nar/gkad312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/21/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Structural analysis of RNA is an important and versatile tool to investigate the function of this type of molecules in the cell as well as in vitro. Several robust and reliable procedures are available, relying on chemical modification inducing RT stops or nucleotide misincorporations during reverse transcription. Others are based on cleavage reactions and RT stop signals. However, these methods address only one side of the RT stop or misincorporation position. Here, we describe Led-Seq, a new approach based on lead-induced cleavage of unpaired RNA positions, where both resulting cleavage products are investigated. The RNA fragments carrying 2', 3'-cyclic phosphate or 5'-OH ends are selectively ligated to oligonucleotide adapters by specific RNA ligases. In a deep sequencing analysis, the cleavage sites are identified as ligation positions, avoiding possible false positive signals based on premature RT stops. With a benchmark set of transcripts in Escherichia coli, we show that Led-Seq is an improved and reliable approach based on metal ion-induced phosphodiester hydrolysis to investigate RNA structures in vivo.
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Affiliation(s)
- Tim Kolberg
- Institute for Biochemistry, Leipzig University, Brüderstr. 34, 04103 Leipzig, Germany
| | - Sarah von Löhneysen
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstr. 16–18, 04107 Leipzig, Germany
| | - Iuliia Ozerova
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstr. 16–18, 04107 Leipzig, Germany
| | - Karolin Wellner
- Institute for Biochemistry, Leipzig University, Brüderstr. 34, 04103 Leipzig, Germany
| | - Roland K Hartmann
- Institute for Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg 6, 35037 Marburg, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstr. 16–18, 04107 Leipzig, Germany
- Max Planck Institute for Mathematics in the Sciences, Inselstraße 22, D-04103 Leipzig, Germany
- Department of Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Wien, Austria
- Facultad de Ciencias, Universidad Nacional de Colombia, Bogotá, Colombia
- Santa Fe Institute, 1399 Hyde Park Rd., Santa Fe, NM 87501, USA
| | - Mario Mörl
- Institute for Biochemistry, Leipzig University, Brüderstr. 34, 04103 Leipzig, Germany
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5
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Lama L, Ryan K. Starting and stopping RNA polymerase III transcription on single-stranded DNA oligonucleotides. RNA (NEW YORK, N.Y.) 2022; 28:1315-1324. [PMID: 35853667 PMCID: PMC9479740 DOI: 10.1261/rna.078981.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 07/06/2022] [Indexed: 06/15/2023]
Abstract
Circularized single-stranded DNA oligonucleotides, or coligos, show promise as promoter-independent RNA polymerase III (Pol III) transcription templates for generating small RNA in human cells. Using a modified small RNA-seq method, we studied the sequence and secondary structure characteristics that determine Pol III initiation and termination on six coligo templates. The coligos each consisted of an imperfectly base-paired stem flanked by one larger and one smaller loop and were unrelated in sequence. Small RNA-seq data from Pol III coligo transcripts revealed a strong preference for initiating transcription within a 5-nucleotide (nt) window spanning the stem-larger loop junction (loop size 11-24 nt). Transcription in all cases proceeded into the stem rather than into the larger loop, indicating the junction is a site-specific, secondary structure-based Pol III transcription initiator. On average, 81% of sequencing reads showed initiation within this 5 nt junction region, with a template start site nucleotide preference of C > T >> A > G, and a requirement for a template purine at Tss-1. Termination was less precise than initiation and occurred in the larger loop at the same end of the stem where transcription initiated. Termination efficiency was on average 82% and was distributed among the first 11 single-stranded larger loop nt following the stem. The size heterogeneity of Pol III coligo transcripts is thus mainly due to 3' end heterogeneity, whereas the RNA 5' ends were more predictable and homogeneous. Transcription termination did not require an oligo dA template sequence, indicating that termination in this context may be mechanistically different than Pol III's normal gene-context termination. A stepwise model for coligo transcription by Pol III is proposed.
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Affiliation(s)
- Lodoe Lama
- Department of Chemistry and Biochemistry, The City College of New York, New York, New York 10031, USA
- Biochemistry and Chemistry Ph.D. Programs, The City University of New York Graduate Center, New York, New York 10016, USA
| | - Kevin Ryan
- Department of Chemistry and Biochemistry, The City College of New York, New York, New York 10031, USA
- Biochemistry and Chemistry Ph.D. Programs, The City University of New York Graduate Center, New York, New York 10016, USA
- Chemistry Ph.D. Programs, The City University of New York Graduate Center, New York, New York 10016, USA
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6
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Olzog VJ, Gärtner C, Stadler PF, Fallmann J, Weinberg CE. cyPhyRNA-seq: a genome-scale RNA-seq method to detect active self-cleaving ribozymes by capturing RNAs with 2',3' cyclic phosphates and 5' hydroxyl ends. RNA Biol 2021; 18:818-831. [PMID: 34906034 PMCID: PMC8782182 DOI: 10.1080/15476286.2021.1999105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Self-cleaving ribozymes are catalytically active RNAs that cleave themselves into a 5′-fragment with a 2′,3′-cyclic phosphate and a 3′-fragment with a 5′-hydroxyl. They are widely applied for the construction of synthetic RNA devices and RNA-based therapeutics. However, the targeted discovery of self-cleaving ribozymes remains a major challenge. We developed a transcriptome-wide method, called cyPhyRNA-seq, to screen for ribozyme cleavage fragments in total RNA extract. This approach employs the specific ligation-based capture of ribozyme 5′-fragments using a variant of the Arabidopsis thaliana tRNA ligase we engineered. To capture ribozyme 3′-fragments, they are enriched from total RNA by enzymatic treatments. We optimized and enhanced the individual steps of cyPhyRNA-seq in vitro and in spike-in experiments. Then, we applied cyPhyRNA-seq to total RNA isolated from the bacterium Desulfovibrio vulgaris and detected self-cleavage of the three predicted type II hammerhead ribozymes, whose activity had not been examined to date. cyPhyRNA-seq can be used for the global analysis of active self-cleaving ribozymes with the advantage to capture both ribozyme cleavage fragments from total RNA. Especially in organisms harbouring many self-cleaving RNAs, cyPhyRNA-seq facilitates the investigation of cleavage activity. Moreover, this method has the potential to be used to discover novel self-cleaving ribozymes in different organisms.
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Affiliation(s)
- V Janett Olzog
- Department of Life Science, Institute for Biochemistry, Leipzig, Germany
| | - Christiane Gärtner
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Leipzig University, Leipzig, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Leipzig University, Leipzig, Germany.,Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany.,Department of Theoretical Chemistry, Vienna, Austria.,Facultad de Ciencias, Universidad National de Colombia, Sede Bogotá, Colombia.,Santa Fe Institute, University of Vienna, Santa Fe, New Mexico, USA
| | - Jörg Fallmann
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, Leipzig University, Leipzig, Germany
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7
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Li J, Lin L, Yu J, Zhai S, Liu G, Tian L. Fabrication and Biomedical Applications of “Polymer-Like” Nucleic Acids Enzymatically Produced by Rolling Circle Amplification. ACS APPLIED BIO MATERIALS 2019; 2:4106-4120. [DOI: 10.1021/acsabm.9b00622] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jing Li
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Boulevard, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Li Lin
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Boulevard, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Jiantao Yu
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Boulevard, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Shiyao Zhai
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Boulevard, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Guoyuan Liu
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Boulevard, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
| | - Leilei Tian
- Department of Materials Science and Engineering, Southern University of Science and Technology, 1088 Xueyuan Boulevard, Nanshan District, Shenzhen, Guangdong 518055, P. R. China
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8
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Shepherd TR, Du RR, Huang H, Wamhoff EC, Bathe M. Bioproduction of pure, kilobase-scale single-stranded DNA. Sci Rep 2019; 9:6121. [PMID: 30992517 PMCID: PMC6467869 DOI: 10.1038/s41598-019-42665-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/05/2019] [Indexed: 11/13/2022] Open
Abstract
Scalable production of kilobase single-stranded DNA (ssDNA) with sequence control has applications in therapeutics, gene synthesis and sequencing, scaffolded DNA origami, and archival DNA memory storage. Biological production of circular ssDNA (cssDNA) using M13 addresses these needs at low cost. However, one unmet goal is to minimize the essential protein coding regions of the exported DNA while maintaining its infectivity and production purity to produce sequences less than 3,000 nt in length, relevant to therapeutic and materials science applications. Toward this end, synthetic miniphage with inserts of custom sequence and size offers scalable, low-cost synthesis of cssDNA at milligram and higher scales. Here, we optimize growth conditions using an E. coli helper strain combined with a miniphage genome carrying only an f1 origin and a β-lactamase-encoding (bla) antibiotic resistance gene, enabling isolation of pure cssDNA with a minimum sequence genomic length of 1,676 nt, without requiring additional purification from contaminating DNA. Low-cost scalability of isogenic, custom-length cssDNA is demonstrated for a sequence of 2,520 nt using a bioreactor, purified with low endotoxin levels (<5 E.U./ml). We apply these exonuclease-resistant cssDNAs to the self-assembly of wireframe DNA origami objects and to encode digital information on the miniphage genome for biological amplification.
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Affiliation(s)
- Tyson R Shepherd
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Rebecca R Du
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Hellen Huang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Eike-Christian Wamhoff
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Mark Bathe
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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9
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Lama L, Cobo J, Buenaventura D, Ryan K. Small RNA-seq: The RNA 5'-end adapter ligation problem and how to circumvent it. J Biol Methods 2019; 6. [PMID: 31080843 PMCID: PMC6507418 DOI: 10.14440/jbm.2019.269] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The preparation of small RNA cDNA sequencing libraries depends on the unbiased ligation of adapters to the RNA ends. Small RNA with 5' recessed ends are poor substrates for enzymatic adapter ligation, but this 5' adapter ligation problem can go undetected if the library preparation steps are not monitored. Here we illustrate the severity of the 5' RNA end ligation problem using several pre-miRNA-like hairpins that allow us to expand the definition of the problem to include 5' ends close to a hairpin stem, whether recessed or in a short extension. The ribosome profiling method can avoid a difficult 5' adapter ligation, but the enzyme typically used to circularize the cDNA has been reported to be biased, calling into question the benefit of this workaround. Using the TS2126 RNA ligase 1 (a.k.a. CircLigase) as the circularizing enzyme, we devised a bias test for the circularization of first strand cDNA. All possible dinucleotides were circle-ligated with similar efficiency. To re-linearize the first strand cDNA in the ribosome profiling approach, we introduce an improved method wherein a single ribonucleotide is placed between the sequencing primer binding sites in the reverse transcriptase primer, which later serves as the point of re-linearization by RNase A. We incorporate this step into the ribosomal profiling method and describe a complete improved library preparation method, Coligo-seq, for the sequencing of small RNA with secondary structure close to the 5' end. This method accepts a variety of 5' modified RNA, including 5' monophosphorylated RNA, as demonstrated by the construction of a HeLa cell microRNA cDNA library.
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Affiliation(s)
- Lodoe Lama
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA.,Biochemistry Ph.D. Program, The City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA
| | - Jose Cobo
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA.,Biochemistry Ph.D. Program, The City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA
| | - Diego Buenaventura
- Biology Ph.D. Program, The City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA
| | - Kevin Ryan
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA.,Biochemistry Ph.D. Program, The City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA.,Chemistry Ph.D. Program, The City University of New York Graduate Center, 365 Fifth Avenue, New York, NY 10016, USA
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10
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Abstract
Nucleic acid amplification is a hugely important technology for biology and medicine. While the polymerase chain reaction (PCR) has been highly useful and effective, its reliance on heating and cooling cycles places some constraints on its utility. For example, the heating step of PCR can destroy biological molecules under investigation and heat/cool cycles are not applicable in living systems. Thus, isothermal approaches to DNA and RNA amplification are under widespread study. Perhaps the simplest of these are the rolling circle approaches, including rolling circle amplification (RCA) and rolling circle transcription (RCT). In this strategy, a very small circular oligonucleotide (e.g., 25-100 nucleotides in length) acts as a template for a DNA or an RNA polymerase, producing long repeating product strands that serve as amplified copies of the circle sequence. Here we describe the early developments and studies involving circular oligonucleotides that ultimately led to the burgeoning rolling circle technologies currently under development. This Account starts with our studies on the design of circular oligonucleotides as novel DNA- and RNA-binding motifs. We describe how we developed chemical and biochemical strategies for synthesis of well-defined circular oligonucleotides having defined sequence and open (unpaired) structure, and we outline the unusual ways in which circular DNAs can interact with other nucleic acids. We proceed next to the discovery of DNA and RNA polymerase activity on these very small cyclic DNAs. DNA polymerase "rolling circle" activities were discovered concurrently in our laboratory and that of Andrew Fire. We describe the surprising efficiency of this process even on shockingly small circular DNAs, producing repeating DNAs thousands of nucleotides in length. RNA polymerase activity on circular oligonucleotides was first documented in our group in 1995; especially surprising in this case was the finding that the process occurs efficiently even without promoter sequences in the circle. We describe how one can encode cleavable sites into the product DNAs and RNAs from RCA/RCT, which can then be resolved into large quantities of almost pure oligonucleotides. Our Account then proceeds with a summary describing a broad variety of tools and methods built in many laboratories around the rolling circle concept. Among the important developments are the discovery of highly efficient DNA polymerases for RCA; the invention of exponential ("hyperbranched") RCA amplification made possible by use of a second primer; the development of the "padlock" process for detection of nucleic acids and proteins coupled with RCA; the use of circular oligonucleotides as vectors in cells to encode biologically active RNAs via RCT; and the use of small DNA circles to encode and extend human telomeres. Finally, we finish with some ideas about where the field may go in the future.
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Affiliation(s)
- Michael G Mohsen
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
| | - Eric T Kool
- Department of Chemistry, Stanford University , Stanford, California 94305, United States
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11
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Patel J, Lama L, Hoffmann NA, Cobo J, Müller CW, Ryan K. RNA polymerase III initiation on coligo DNA templates containing loops of variable sequence, size and nucleotide chemistry. Gene 2016; 612:49-54. [PMID: 27593562 DOI: 10.1016/j.gene.2016.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/23/2016] [Accepted: 09/01/2016] [Indexed: 10/21/2022]
Abstract
Circularized oligonucleotides, or coligos, were previously found to serve as RNA polymerase III (Pol III) templates in vitro and in human tissue culture cells. Here we randomized the 12-nucleotide larger loop (L-loop) of a well characterized coligo and found unexpectedly that in vitro transcription by FLAG-Pol III was not significantly affected. This observation allowed us to test the variable of coligo L-loop size separately from the variable of its sequence. Transcription efficiency increased with L-loop size from 3 to 12 nucleotides of randomized sequence, and the smallest loop forced initiation to move into the stem region. To test further the need for any specific sequence we compared seven nucleotide L-loops composed of random, abasic and abasic-acyclic nucleotides, and all supported transcription by Pol III. Transcription of a series of coligos containing twelve contiguous randomized nucleotides placed at different locations within the coligo structure provided further evidence that the stem-loop junction structure is important for precise initiation. Nearly the same transcript pattern was formed in vitro by Pol III from yeast and human cells. Overall, these experiments support structure, rather than L-loop sequence, as the major determinant of coligo transcription initiation by Pol III.
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Affiliation(s)
- Joy Patel
- Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY, USA
| | - Lodoe Lama
- Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY, USA; Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
| | - Niklas A Hoffmann
- European Molecular Biology Laboratory (EMBL) Structural and Computational Biology Unit, Meyerhofstrasse 1, 67117 Heidelberg, Germany
| | - Jose Cobo
- Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY, USA; Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
| | - Christoph W Müller
- European Molecular Biology Laboratory (EMBL) Structural and Computational Biology Unit, Meyerhofstrasse 1, 67117 Heidelberg, Germany
| | - Kevin Ryan
- Department of Chemistry and Biochemistry, The City College of New York, 160 Convent Avenue, New York, NY, USA; Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA; Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA.
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Lama L, Ryan K. Adenylylation of small RNA sequencing adapters using the TS2126 RNA ligase I. RNA (NEW YORK, N.Y.) 2016; 22:155-61. [PMID: 26567315 PMCID: PMC4691829 DOI: 10.1261/rna.054999.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 06/25/2015] [Indexed: 05/27/2023]
Abstract
Many high-throughput small RNA next-generation sequencing protocols use 5' preadenylylated DNA oligonucleotide adapters during cDNA library preparation. Preadenylylation of the DNA adapter's 5' end frees from ATP-dependence the ligation of the adapter to RNA collections, thereby avoiding ATP-dependent side reactions. However, preadenylylation of the DNA adapters can be costly and difficult. The currently available method for chemical adenylylation of DNA adapters is inefficient and uses techniques not typically practiced in laboratories profiling cellular RNA expression. An alternative enzymatic method using a commercial RNA ligase was recently introduced, but this enzyme works best as a stoichiometric adenylylating reagent rather than a catalyst and can therefore prove costly when several variant adapters are needed or during scale-up or high-throughput adenylylation procedures. Here, we describe a simple, scalable, and highly efficient method for the 5' adenylylation of DNA oligonucleotides using the thermostable RNA ligase 1 from bacteriophage TS2126. Adapters with 3' blocking groups are adenylylated at >95% yield at catalytic enzyme-to-adapter ratios and need not be gel purified before ligation to RNA acceptors. Experimental conditions are also reported that enable DNA adapters with free 3' ends to be 5' adenylylated at >90% efficiency.
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Affiliation(s)
- Lodoe Lama
- Department of Chemistry, The City College of New York, The City University of New York, New York, New York 10031, USA Biochemistry Ph.D. Program, The City University of New York Graduate Center, New York, New York 10016, USA
| | - Kevin Ryan
- Department of Chemistry, The City College of New York, The City University of New York, New York, New York 10031, USA Biochemistry Ph.D. Program, The City University of New York Graduate Center, New York, New York 10016, USA
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13
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Shopsowitz KE, Wu C, Liu G, Dreaden EC, Hammond PT. Periodic-shRNA molecules are capable of gene silencing, cytotoxicity and innate immune activation in cancer cells. Nucleic Acids Res 2015; 44:545-57. [PMID: 26704983 PMCID: PMC4737167 DOI: 10.1093/nar/gkv1488] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/04/2015] [Indexed: 12/24/2022] Open
Abstract
Large dsRNA molecules can cause potent cytotoxic and immunostimulatory effects through the activation of pattern recognition receptors; however, synthetic versions of these molecules are mostly limited to simple sequences like poly-I:C and poly-A:U. Here we show that large RNA molecules generated by rolling circle transcription fold into periodic-shRNA (p-shRNA) structures and cause potent cytotoxicity and gene silencing when delivered to cancer cells. We determined structural requirements for the dumbbell templates used to synthesize p-shRNA, and showed that these molecules likely adopt a co-transcriptionally folded structure. The cytotoxicity of p-shRNA was robustly observed across four different cancer cell lines using two different delivery systems. Despite having a considerably different folded structure than conventional dsRNA, the cytotoxicity of p-shRNA was either equal to or substantially greater than that of poly-I:C depending on the delivery vehicle. Furthermore, p-shRNA caused greater NF-κB activation in SKOV3 cells compared to poly-I:C, indicating that it is a powerful activator of innate immunity. The tuneable sequence and combined gene silencing, immunostimulatory and cytotoxic capacity of p-shRNA make it an attractive platform for cancer immunotherapy.
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Affiliation(s)
- Kevin E Shopsowitz
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Connie Wu
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Gina Liu
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Erik C Dreaden
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Paula T Hammond
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Yang H, Seela F. Circular DNA by "Bis-Click" Ligation: Template-Independent Intramolecular Circularization of Oligonucleotides with Terminal Alkynyl Groups Utilizing Bifunctional Azides. Chemistry 2015; 22:1435-44. [PMID: 26685101 DOI: 10.1002/chem.201503615] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Indexed: 12/19/2022]
Abstract
A highly effective and convenient "bis-click" strategy was developed for the template-independent circularization of single-stranded oligonucleotides by employing copper(I)-assisted azide-alkyne cycloaddition. Terminal triple bonds were incorporated at both ends of linear oligonucleotides. Alkynylated 7-deaza-2'-deoxyadenosine and 2'-deoxyuridine residues with different side chains were used in solid-phase synthesis with phosphoramidite chemistry. The bis-click ligation of linear 9- to 36-mer oligonucleotides with 1,4-bis(azidomethyl)benzene afforded circular DNA in a simple and selective way; azido modification of the oligonucleotide was not necessary. Short ethynyl side chains were compatible with the circularization of longer oligonucleotides, whereas octadiynyl residues were used for short 9-mers. Compared with linear duplexes, circular bis-click constructs exhibit a significantly increased duplex stability over their linear counterparts. The intramolecular bis-click ligation protocol is not limited to DNA, but may also be suitable for the construction of other macrocycles, such as circular RNAs, peptides, or polysaccharides.
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Affiliation(s)
- Haozhe Yang
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149, Münster, Germany.,Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie neuer Materialien, Universität Osnabrück, Barbarastrasse 7, 49069, Osnabrück, Germany), Fax: (+49) 251-53406857
| | - Frank Seela
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149, Münster, Germany. .,Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie neuer Materialien, Universität Osnabrück, Barbarastrasse 7, 49069, Osnabrück, Germany), Fax: (+49) 251-53406857.
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Lama L, Seidl CI, Ryan K. New insights into the promoterless transcription of DNA coligo templates by RNA polymerase III. Transcription 2015; 5:e27913. [PMID: 25764216 PMCID: PMC4214238 DOI: 10.4161/trns.27913] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Chemically synthesized DNA can carry small RNA sequence information but converting that information into small RNA is generally thought to require large double-stranded promoters in the context of plasmids, viruses and genes. We previously found evidence that circularized oligodeoxynucleotides (coligos) containing certain sequences and secondary structures can template the synthesis of small RNA by RNA polymerase III in vitro and in human cells. By using immunoprecipitated RNA polymerase III we now report corroborating evidence that this enzyme is the sole polymerase responsible for coligo transcription. The immobilized polymerase enabled experiments showing that coligo transcripts can be formed through transcription termination without subsequent 3' end trimming. To better define the determinants of productive transcription, a structure-activity relationship study was performed using over 20 new coligos. The results show that unpaired nucleotides in the coligo stem facilitate circumtranscription, but also that internal loops and bulges should be kept small to avoid secondary transcription initiation sites. A polymerase termination sequence embedded in the double-stranded region of a hairpin-encoding coligo stem can antagonize transcription. Using lessons learned from new and old coligos, we demonstrate how to convert poorly transcribed coligos into productive templates. Our findings support the possibility that coligos may prove useful as chemically synthesized vectors for the ectopic expression of small RNA in human cells.
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Affiliation(s)
- Lodoe Lama
- a Department of Chemistry; The City College of New York; The City University of New York; New York, NY USA
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Shopsowitz KE, Roh YH, Deng ZJ, Morton SW, Hammond PT. RNAi-microsponges form through self-assembly of the organic and inorganic products of transcription. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2014; 10:1623-33. [PMID: 24851252 PMCID: PMC4031615 DOI: 10.1002/smll.201302676] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Inorganic nanostructures have been used extensively to package nucleic acids into forms useful for therapeutic applications. Here we report that the two products of transcription, RNA and inorganic pyrophosphate, can self-assemble to form composite microsponge structures composed of nanocrystalline magnesium pyrophosphate sheets (Mg₂P₂O₇•3.5H₂O) with RNA adsorbed to their surfaces. The microsponge particles contain high loadings of RNA (15-21 wt.%) that are protected from degradation and can be obtained through a rolling circle mechanism as large concatemers capable of mediating RNAi. The morphology of the RNAi microsponges is influenced by the time-course of the transcription reaction and interactions between RNA and the inorganic phase. Previous work demonstrated that polycations can be used to condense RNAi microsponges into nanoparticles capable of efficient transfection with low toxicity. Our new findings suggest that the formation of these nanoparticles is mediated by the gradual dissolution of magnesium pyrophosphate that occurs in the presence of polycations. The simple one-pot approach for assembling RNAi microsponges along with their unique properties could make them useful for RNA-based therapeutics.
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Affiliation(s)
- Kevin E. Shopsowitz
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA
| | - Young Hoon Roh
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA
| | - Zhou J. Deng
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA
| | - Stephen W. Morton
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA
| | - Paula T. Hammond
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Rm 76-553, Cambridge, MA 02139, USA
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Swaminathan S, Murray DD, Kelleher AD. miRNAs and HIV: unforeseen determinants of host-pathogen interaction. Immunol Rev 2014; 254:265-80. [PMID: 23772625 DOI: 10.1111/imr.12077] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Our understanding of the complexity of gene regulation has significantly improved in the last decade as the role of small non-coding RNAs, called microRNAs (miRNAs), has been appreciated. These 19-22 nucleotide RNA molecules are critical regulators of mRNA translation and turnover. The miRNAs bind via a protein complex to the 3' untranslated region (3' UTR) of mRNA, ultimately leading to mRNA translational inhibition, degradation, or repression. Although many mechanisms by which human immunodeficiency virus-1 (HIV-1) infection eventually induces catastrophic immune destruction have been elucidated, the important role that miRNAs play in HIV-1 pathogenesis is only now emerging. Accumulating evidence demonstrates that changes to endogenous miRNA levels following infection is important: in maintaining HIV-1 latency in resting CD4(+) T cells, potentially affect immune function via changes to cytokines such as interleukin-2 (IL-2) and IL-10 and may predict disease progression. We review the roles that both viral and host miRNAs play in different cell types and disease conditions that are important in HIV-1 infection and discuss how miRNAs affect key immunomodulatory molecules contributing to immune dysfunction. Further, we discuss whether miRNAs may be used as novel biomarkers in serum and the potential to modulate miRNA levels as a unique approach to combating this pathogen.
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Affiliation(s)
- Sanjay Swaminathan
- Laboratory of Human Retrovirology, Applied and Developmental Research Directorate (ADD), Science Application International Corporation (SAIC)-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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Seidl CI, Lama L, Ryan K. Circularized synthetic oligodeoxynucleotides serve as promoterless RNA polymerase III templates for small RNA generation in human cells. Nucleic Acids Res 2012; 41:2552-64. [PMID: 23275570 PMCID: PMC3575851 DOI: 10.1093/nar/gks1334] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Synthetic RNA formulations and viral vectors are the two main approaches for delivering small therapeutic RNA to human cells. Here we report findings supporting an alternative strategy in which an endogenous human RNA polymerase (RNAP) is harnessed to make RNA hairpin-containing small RNA from synthetic single-stranded DNA oligonucleotides. We report that circularizing a DNA template strand encoding a pre-microRNA hairpin mimic can trigger its circumtranscription by human RNAP III in vitro and in human cells. Sequence and secondary structure preferences that appear to promote productive transcription are described. The circular topology of the template is required for productive transcription, at least in part, to stabilize the template against exonucleases. In contrast to bacteriophage and Escherichia coli RNAPs, human RNAPs do not carry out rolling circle transcription on circularized templates. While transfected DNA circles distribute between the nucleus and cytosol, their transcripts are found mainly in the cytosol. Circularized oligonucleotides are synthetic, free of the hazards of viral vectors and maintain small RNA information in a stable form that RNAP III can access in a cellular context with, in some cases, near promoter-like precision and biologically relevant efficiency.
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Affiliation(s)
- Christine I Seidl
- Department of Chemistry, The City College of New York, New York, NY 10031, USA
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Abstract
There has been a paradigm shift in our understanding of how protein regulation occurs within mammalian cells in the last 15 years. Our current understanding is that small, noncoding RNA molecules called microRNAs (miRNAs) play a vital role in modulating the translation of mRNAs into protein. Important studies suggest that HIV-1 replication may be restricted by certain host cellular miRNAs, and this in turn may play pivotal roles in host defense and in maintaining latency within resting CD4 T cells. Conversely, host cellular miRNAs have also been demonstrated to be essential for certain viruses to establish infection and the altered expression of cellular miRNAs in the setting of HIV-1 may also be a factor favoring viral replication. The differential expression of important protective histocompatability locus antigen (HLA) alleles in HIV-1 infection has recently been shown to be regulated by miRNAs. To date, most efforts into finding an effective vaccine to combat HIV-1 have not been successful. Understanding the role that miRNAs may play in HIV-1 pathogenesis may allow a different approach to targeting key small RNAs or the identification of new important protein targets regulated by miRNAs, which may result in a better vaccine construct. The purpose of this review is to look at our current state of understanding of how HIV-1 and the miRNA pathway interact and the possible therapeutic interventions that this knowledge may entail.
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