1
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Huang SH, Chen SC, Wu TY, Chen CY, Yu CH. Programmable modulation of ribosomal frameshifting by mRNA targeting CRISPR-Cas12a system. iScience 2023; 26:108492. [PMID: 38125012 PMCID: PMC10730746 DOI: 10.1016/j.isci.2023.108492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/13/2023] [Accepted: 11/16/2023] [Indexed: 12/23/2023] Open
Abstract
Minus 1 programmed ribosomal frameshifting (-1 PRF) is a conserved translational regulation event essential for critical biological processes, including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication. Efficient trans-modulation of the structured RNA element crucial to -1 PRF will endow the therapeutic application. Here, we demonstrate that CRISPR RNA can stimulate efficient -1 PRF. Assembled CRISPR-Cas12a, but not CRISPR-Cas9, complex further enhances -1 PRF efficiency through its higher capacity to stall translating ribosomes. We additionally perform CRISPR-Cas12a targeting to impair the SARS-CoV-2 frameshifting pseudoknot structure via a focused screening. We demonstrate that targeting CRISPR-Cas12a results in more than 70% suppression of -1 PRF in vitro and about 50% suppression in mammalian cells. Our results show the expanded function of the CRISPR-Cas12 system in modulating -1 PRF efficiency through stalling ribosomes and deforming frameshifting stimulatory signals, which could serve as a new strategy for future coronavirus pandemics.
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Affiliation(s)
- Shih-Hong Huang
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shih-Cheng Chen
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | | | - Cheng-Yao Chen
- YD BioLabs, Inc., Hsinchu, Taiwan
- School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei, Taiwan
| | - Chien-Hung Yu
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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2
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Zhang J, Fakharzadeh A, Roland C, Sagui C. RNA as a Major-Groove Ligand: RNA-RNA and RNA-DNA Triplexes Formed by GAA and UUC or TTC Sequences. ACS OMEGA 2022; 7:38728-38743. [PMID: 36340174 PMCID: PMC9631886 DOI: 10.1021/acsomega.2c04358] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Friedreich's ataxia is associated with noncanonical nucleic acid structures that emerge when GAA:TTC repeats in the first intron of the FXN gene expand beyond a critical number of repeats. Specifically, the noncanonical repeats are associated with both triplexes and R-loops. Here, we present an in silico investigation of all possible triplexes that form by attaching a third RNA strand to an RNA:RNA or DNA:DNA duplex, complementing previous DNA-based triplex studies. For both new triplexes results are similar. For a pyridimine UUC+ third strand, the parallel orientation is stable while its antiparallel counterpart is unstable. For a neutral GAA third strand, the parallel conformation is stable. A protonated GA+A third strand is stable in both parallel and antiparallel orientations. We have also investigated Na+ and Mg2+ ion distributions around the triplexes. The presence of Mg2+ ions helps stabilize neutral, antiparallel GAA triplexes. These results (along with previous DNA-based studies) allow for the emergence of a complete picture of the stability and structural characteristics of triplexes based on the GAA and TTC/UUC sequences, thereby contributing to the field of trinucleotide repeats and the associated unusual structures that trigger expansion.
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3
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Yang L, Toh DFK, Krishna MS, Zhong Z, Liu Y, Wang S, Gong Y, Chen G. Tertiary Base Triple Formation in the SRV-1 Frameshifting Pseudoknot Stabilizes Secondary Structure Components. Biochemistry 2020; 59:4429-4438. [PMID: 33166472 DOI: 10.1021/acs.biochem.0c00611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Minor-groove base triples formed between stem 1 and loop 2 of the simian retrovirus type 1 (SRV-1) mRNA frameshifting pseudoknot are essential in stimulating -1 ribosomal frameshifting. How tertiary base triple formation affects the local stabilities of secondary structures (stem 1 and stem 2) and thus ribosomal frameshifting efficiency is not well understood. We made a short peptide nucleic acid (PNA) that is expected to invade stem 1 of the SRV-1 pseudoknot by PNA-RNA duplex formation to mimic the stem 1 unwinding process by a translating ribosome. In addition, we used a PNA for invading stem 2 in the SRV-1 pseudoknot. Our nondenaturing polyacrylamide gel electrophoresis data for the binding of PNA to the SRV-1 pseudoknot and mutants reveal that mutations in loop 2 disrupting base triple formation between loop 2 and stem 1 in the SRV-1 pseudoknot result in enhanced invasion by both PNAs. Our data suggest that tertiary stem 1-loop 2 base triple interactions in the SRV-1 pseudoknot can stabilize both of the secondary structural components, stem 1 and stem 2. Stem 2 stability is thus coupled to the structural stability of stem 1-loop 2 base triples, mediated through a long-range effect. The apparent dissociation constants of both PNAs are positively correlated with the pseudoknot mechanical stabilities and frameshifting efficiencies. The relatively simple PNA local invasion experiment may be used to characterize the energetic contribution of tertiary interactions and ligand binding in many other RNA and DNA structures.
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Affiliation(s)
- Lixia Yang
- School of Life Science and Technology, University of Electronic Science and Technology of China, No. 4, Section 2, North Jianshe Road, Chengdu, Sichuan 610054, P. R. China.,School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen), No. 2001 Longxiang Boulevard, Longgang District, Shenzhen, Guangdong 518172, P. R. China.,Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Desiree-Faye Kaixin Toh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Manchugondanahalli S Krishna
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Zhensheng Zhong
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Yiyao Liu
- School of Life Science and Technology, University of Electronic Science and Technology of China, No. 4, Section 2, North Jianshe Road, Chengdu, Sichuan 610054, P. R. China
| | - Shaomeng Wang
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, No. 4, Section 2, North Jianshe Road, Chengdu, Sichuan 610054, P. R. China
| | - Yubin Gong
- School of Electronic Science and Engineering, University of Electronic Science and Technology of China, No. 4, Section 2, North Jianshe Road, Chengdu, Sichuan 610054, P. R. China
| | - Gang Chen
- School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen (CUHK-Shenzhen), No. 2001 Longxiang Boulevard, Longgang District, Shenzhen, Guangdong 518172, P. R. China.,Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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4
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Thulson E, Hartwick EW, Cooper-Sansone A, Williams MAC, Soliman ME, Robinson LK, Kieft JS, Mouzakis KD. An RNA pseudoknot stimulates HTLV-1 pro-pol programmed -1 ribosomal frameshifting. RNA (NEW YORK, N.Y.) 2020; 26:512-528. [PMID: 31980578 PMCID: PMC7075266 DOI: 10.1261/rna.070490.119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
Programmed -1 ribosomal frameshifts (-1 PRFs) are commonly used by viruses to regulate their enzymatic and structural protein levels. Human T-cell leukemia virus type 1 (HTLV-1) is a carcinogenic retrovirus that uses two independent -1 PRFs to express viral enzymes critical to establishing new HTLV-1 infections. How the cis-acting RNA elements in this viral transcript function to induce frameshifting is unknown. The objective of this work was to conclusively define the 3' boundary of and the RNA elements within the HTLV-1 pro-pol frameshift site. We hypothesized that the frameshift site structure was a pseudoknot and that its 3' boundary would be defined by the pseudoknot's 3' end. To test these hypotheses, the in vitro frameshift efficiencies of three HTLV-1 pro-pol frameshift sites with different 3' boundaries were quantified. The results indicated that nucleotides included in the longest construct were essential to highly efficient frameshift stimulation. Interestingly, only this construct could form the putative frameshift site pseudoknot. Next, the secondary structure of this frameshift site was determined. The dominant structure was an H-type pseudoknot which, together with the slippery sequence, stimulated frameshifting to 19.4(±0.3)%. The pseudoknot's critical role in frameshift stimulation was directly revealed by examining the impact of structural changes on HTLV-1 pro-pol -1 PRF. As predicted, mutations that occluded pseudoknot formation drastically reduced the frameshift efficiency. These results are significant because they demonstrate that a pseudoknot is important to HTLV-1 pro-pol -1 PRF and define the frameshift site's 3' boundary.
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Affiliation(s)
- Eliza Thulson
- Department of Chemistry and Biochemistry, Fort Lewis College, Durango, Colorado 81301, USA
| | - Erik W Hartwick
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Andrew Cooper-Sansone
- Department of Chemistry and Biochemistry, Fort Lewis College, Durango, Colorado 81301, USA
| | - Marcus A C Williams
- Department of Chemistry and Biochemistry, Fort Lewis College, Durango, Colorado 81301, USA
| | - Mary E Soliman
- Department of Chemistry and Biochemistry, Loyola Marymount University, Los Angeles, California 90045, USA
| | - Leila K Robinson
- Department of Chemistry and Biochemistry, Loyola Marymount University, Los Angeles, California 90045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA Bioscience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Kathryn D Mouzakis
- Department of Chemistry and Biochemistry, Loyola Marymount University, Los Angeles, California 90045, USA
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5
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Puah RY, Jia H, Maraswami M, Toh DFK, Ero R, Yang L, Patil KM, Ong AAL, Krishna MS, Sun R, Tong C, Huang M, Chen X, Loh TP, Gao YG, Liu DX, Chen G. Selective Binding to mRNA Duplex Regions by Chemically Modified Peptide Nucleic Acids Stimulates Ribosomal Frameshifting. Biochemistry 2017; 57:149-159. [PMID: 29116759 DOI: 10.1021/acs.biochem.7b00744] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Minus-one programmed ribosomal frameshifting (-1 PRF) allows the precise maintenance of the ratio between viral proteins and is involved in the regulation of the half-lives of cellular mRNAs. Minus-one ribosomal frameshifting is activated by several stimulatory elements such as a heptameric slippery sequence (X XXY YYZ) and an mRNA secondary structure (hairpin or pseudoknot) that is positioned 2-8 nucleotides downstream from the slippery site. Upon -1 RF, the ribosomal reading frame is shifted from the normal zero frame to the -1 frame with the heptameric slippery sequence decoded as XXX YYY Z instead of X XXY YYZ. Our research group has developed chemically modified peptide nucleic acid (PNA) L and Q monomers to recognize G-C and C-G Watson-Crick base pairs, respectively, through major-groove parallel PNA·RNA-RNA triplex formation. L- and Q-incorporated PNAs show selective binding to double-stranded RNAs (dsRNAs) over single-stranded RNAs (ssRNAs). The sequence specificity and structural selectivity of L- and Q-modified PNAs may allow the precise targeting of desired viral and cellular RNA structures, and thus may serve as valuable biological tools for mechanistic studies and potential therapeutics for fighting diseases. Here, for the first time, we demonstrate by cell-free in vitro translation assays using rabbit reticulocyte lysate that the dsRNA-specific chemically modified PNAs targeting model mRNA hairpins stimulate -1 RF (from 2% to 32%). An unmodified control PNA, however, shows nonspecific inhibition of translation. Our results suggest that the modified dsRNA-binding PNAs may be advantageous for targeting structured RNAs.
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Affiliation(s)
| | | | | | | | - Rya Ero
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551
| | | | | | | | | | | | | | - Mei Huang
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551
| | | | | | - Yong-Gui Gao
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551
| | - Ding Xiang Liu
- School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, Singapore 637551.,Guangdong Province Key Laboratory Microbial Signals & Disease Co, and Integrative Microbiology Research Centre, South China Agricultural University , Guangzhou 510642, Guangdong, People's Republic of China
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6
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Q Nguyen KK, Gomez YK, Bakhom M, Radcliffe A, La P, Rochelle D, Lee JW, Sorin EJ. Ensemble simulations: folding, unfolding and misfolding of a high-efficiency frameshifting RNA pseudoknot. Nucleic Acids Res 2017; 45:4893-4904. [PMID: 28115636 PMCID: PMC5416846 DOI: 10.1093/nar/gkx012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 01/11/2017] [Indexed: 12/11/2022] Open
Abstract
Massive all-atom molecular dynamics simulations were conducted across a distributed computing network to study the folding, unfolding, misfolding and conformational plasticity of the high-efficiency frameshifting double mutant of the 26 nt potato leaf roll virus RNA pseudoknot. Our robust sampling, which included over 40 starting structures spanning the spectrum from the extended unfolded state to the native fold, yielded nearly 120 μs of cumulative sampling time. Conformational microstate transitions on the 1.0 ns to 10.0 μs timescales were observed, with post-equilibration sampling providing detailed representations of the conformational free energy landscape and the complex folding mechanism inherent to the pseudoknot motif. Herein, we identify and characterize two alternative native structures, three intermediate states, and numerous misfolded states, the latter of which have not previously been characterized via atomistic simulation techniques. While in line with previous thermodynamics-based models of a general RNA folding mechanism, our observations indicate that stem-strand-sequence-separation may serve as an alternative predictor of the order of stem formation during pseudoknot folding. Our results contradict a model of frameshifting based on structural rigidity and resistance to mechanical unfolding, and instead strongly support more recent studies in which conformational plasticity is identified as a determining factor in frameshifting efficiency.
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Affiliation(s)
- Khai K Q Nguyen
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA.,Department of Computer Engineering & Computer Science, California State University Long Beach, Long Beach, CA 90840, USA
| | - Yessica K Gomez
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA.,Department of Physics & Astronomy, California State University Long Beach, Long Beach, CA 90840, USA
| | - Mona Bakhom
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA
| | - Amethyst Radcliffe
- Department of Physics & Astronomy, California State University Long Beach, Long Beach, CA 90840, USA
| | - Phuc La
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA
| | - Dakota Rochelle
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA
| | - Ji Won Lee
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA
| | - Eric J Sorin
- Department of Chemistry & Biochemistry, California State University Long Beach, Long Beach, CA 90840, USA
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7
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Chen YT, Chang KC, Hu HT, Chen YL, Lin YH, Hsu CF, Chang CF, Chang KY, Wen JD. Coordination among tertiary base pairs results in an efficient frameshift-stimulating RNA pseudoknot. Nucleic Acids Res 2017; 45:6011-6022. [PMID: 28334864 PMCID: PMC5449628 DOI: 10.1093/nar/gkx134] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 02/14/2017] [Accepted: 02/17/2017] [Indexed: 12/28/2022] Open
Abstract
Frameshifting is an essential process that regulates protein synthesis in many viruses. The ribosome may slip backward when encountering a frameshift motif on the messenger RNA, which usually contains a pseudoknot structure involving tertiary base pair interactions. Due to the lack of detailed molecular explanations, previous studies investigating which features of the pseudoknot are important to stimulate frameshifting have presented diverse conclusions. Here we constructed a bimolecular pseudoknot to dissect the interior tertiary base pairs and used single-molecule approaches to assess the structure targeted by ribosomes. We found that the first ribosome target stem was resistant to unwinding when the neighboring loop was confined along the stem; such constrained conformation was dependent on the presence of consecutive adenosines in this loop. Mutations that disrupted the distal base triples abolished all remaining tertiary base pairs. Changes in frameshifting efficiency correlated with the stem unwinding resistance. Our results demonstrate that various tertiary base pairs are coordinated inside a highly efficient frameshift-stimulating RNA pseudoknot and suggest a mechanism by which mechanical resistance of the pseudoknot may persistently act on translocating ribosomes.
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Affiliation(s)
- Yu-Ting Chen
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Kai-Chun Chang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Hao-Teng Hu
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Yi-Lan Chen
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
| | - You-Hsin Lin
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Chiung-Fang Hsu
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Cheng-Fu Chang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
| | - Kung-Yao Chang
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Jin-Der Wen
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 10617, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei 10617, Taiwan
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan
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8
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Zhong Z, Yang L, Zhang H, Shi J, Vandana JJ, Lam DTUH, Olsthoorn RCL, Lu L, Chen G. Mechanical unfolding kinetics of the SRV-1 gag-pro mRNA pseudoknot: possible implications for -1 ribosomal frameshifting stimulation. Sci Rep 2016; 6:39549. [PMID: 28000744 PMCID: PMC5175198 DOI: 10.1038/srep39549] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/24/2016] [Indexed: 12/19/2022] Open
Abstract
Minus-one ribosomal frameshifting is a translational recoding mechanism widely utilized by many RNA viruses to generate accurate ratios of structural and catalytic proteins. An RNA pseudoknot structure located in the overlapping region of the gag and pro genes of Simian Retrovirus type 1 (SRV-1) stimulates frameshifting. However, the experimental characterization of SRV-1 pseudoknot (un)folding dynamics and the effect of the base triple formation is lacking. Here, we report the results of our single-molecule nanomanipulation using optical tweezers and theoretical simulation by steered molecular dynamics. Our results directly reveal that the energetic coupling between loop 2 and stem 1 via minor-groove base triple formation enhances the mechanical stability. The terminal base pair in stem 1 (directly in contact with a translating ribosome at the slippery site) also affects the mechanical stability of the pseudoknot. The -1 frameshifting efficiency is positively correlated with the cooperative one-step unfolding force and inversely correlated with the one-step mechanical unfolding rate at zero force. A significantly improved correlation was observed between -1 frameshifting efficiency and unfolding rate at forces of 15-35 pN, consistent with the fact that the ribosome is a force-generating molecular motor with helicase activity. No correlation was observed between thermal stability and -1 frameshifting efficiency.
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Affiliation(s)
- Zhensheng Zhong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Lixia Yang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Haiping Zhang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | - Jiahao Shi
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - J. Jeya Vandana
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
| | - Do Thuy Uyen Ha Lam
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
- St Andrew’s Junior College, 5 Sorby Adams Drive, 357691 Singapore
| | - René C. L. Olsthoorn
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551 Singapore
| | - Gang Chen
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, 637371 Singapore
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9
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Atkins JF, Loughran G, Bhatt PR, Firth AE, Baranov PV. Ribosomal frameshifting and transcriptional slippage: From genetic steganography and cryptography to adventitious use. Nucleic Acids Res 2016; 44:7007-78. [PMID: 27436286 PMCID: PMC5009743 DOI: 10.1093/nar/gkw530] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/26/2016] [Indexed: 12/15/2022] Open
Abstract
Genetic decoding is not ‘frozen’ as was earlier thought, but dynamic. One facet of this is frameshifting that often results in synthesis of a C-terminal region encoded by a new frame. Ribosomal frameshifting is utilized for the synthesis of additional products, for regulatory purposes and for translational ‘correction’ of problem or ‘savior’ indels. Utilization for synthesis of additional products occurs prominently in the decoding of mobile chromosomal element and viral genomes. One class of regulatory frameshifting of stable chromosomal genes governs cellular polyamine levels from yeasts to humans. In many cases of productively utilized frameshifting, the proportion of ribosomes that frameshift at a shift-prone site is enhanced by specific nascent peptide or mRNA context features. Such mRNA signals, which can be 5′ or 3′ of the shift site or both, can act by pairing with ribosomal RNA or as stem loops or pseudoknots even with one component being 4 kb 3′ from the shift site. Transcriptional realignment at slippage-prone sequences also generates productively utilized products encoded trans-frame with respect to the genomic sequence. This too can be enhanced by nucleic acid structure. Together with dynamic codon redefinition, frameshifting is one of the forms of recoding that enriches gene expression.
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Affiliation(s)
- John F Atkins
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland School of Microbiology, University College Cork, Cork, Ireland Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Gary Loughran
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Pramod R Bhatt
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Hills Road, Cambridge CB2 0QQ, UK
| | - Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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10
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Abstract
Since the first description of the canonical B-form DNA double helix, it has been suggested that alternative DNA, DNA–RNA, and RNA structures exist and act as functional genomic elements. Indeed, over the past few years it has become clear that, in addition to serving as a repository for genetic information, genomic DNA elicits biological responses by adopting conformations that differ from the canonical right-handed double helix, and by interacting with RNA molecules to form complex secondary structures. This review focuses on recent advances on three-stranded (triplex) nucleic acids, with an emphasis on DNA–RNA and RNA–RNA interactions. Emerging work reveals that triplex interactions between noncoding RNAs and duplex DNA serve as platforms for delivering site-specific epigenetic marks critical for the regulation of gene expression. Additionally, an increasing body of genetic and structural studies demonstrates that triplex RNA–RNA interactions are essential for performing catalytic and regulatory functions in cellular nucleoprotein complexes, including spliceosomes and telomerases, and for enabling protein recoding during programmed ribosomal frameshifting. Thus, evidence is mounting that DNA and RNA triplex interactions are implemented to perform a range of diverse biological activities in the cell, some of which will be discussed in this review.
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Affiliation(s)
- Albino Bacolla
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, Austin, Texas, United States of America
| | - Guliang Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, Austin, Texas, United States of America
| | - Karen M. Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute, Austin, Texas, United States of America
- * E-mail:
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11
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Yu CH, Olsthoorn RC. Monitoring Ribosomal Frameshifting as a Platform to Screen Anti-Riboswitch Drug Candidates. Methods Enzymol 2015; 550:385-93. [DOI: 10.1016/bs.mie.2014.10.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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12
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Devi G, Zhou Y, Zhong Z, Toh DFK, Chen G. RNA triplexes: from structural principles to biological and biotech applications. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:111-28. [DOI: 10.1002/wrna.1261] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 06/30/2014] [Accepted: 07/14/2014] [Indexed: 12/29/2022]
Affiliation(s)
- Gitali Devi
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore Singapore
| | - Yuan Zhou
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore Singapore
| | - Zhensheng Zhong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore Singapore
| | - Desiree-Faye Kaixin Toh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore Singapore
| | - Gang Chen
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences; Nanyang Technological University; Singapore Singapore
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13
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Anti-frameshifting ligand reduces the conformational plasticity of the SARS virus pseudoknot. J Am Chem Soc 2014; 136:2196-9. [PMID: 24446874 DOI: 10.1021/ja410344b] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Programmed -1 ribosomal frameshifting (-1 PRF) stimulated by mRNA pseudoknots regulates gene expression in many viruses, making pseudoknots potential targets for anti-viral drugs. The mechanism by which pseudoknots trigger -1 PRF, however, remains controversial, with several competing models. Recent work showed that high -1 PRF efficiency was linked to high pseudoknot conformational plasticity via the formation of alternate conformers. We tested whether pseudoknots bound with an anti-frameshifting ligand exhibited a similar correlation between conformational plasticity and -1 PRF efficiency by measuring the effects of a ligand that was found to inhibit -1 PRF in the SARS coronavirus on the conformational dynamics of the SARS pseudoknot. Using single-molecule force spectroscopy to unfold pseudoknots mechanically, we found that the ligand binding effectively abolished the formation of alternate conformers. This result extends the connection between -1 PRF and conformational dynamics and, moreover, suggests that targeting the conformational dynamics of pseudoknots may be an effective strategy for anti-viral drug design.
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Yu CH, Luo J, Iwata-Reuyl D, Olsthoorn RCL. Exploiting preQ(1) riboswitches to regulate ribosomal frameshifting. ACS Chem Biol 2013; 8:733-40. [PMID: 23327288 DOI: 10.1021/cb300629b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Knowing the molecular details of the interaction between riboswitch aptamers and their corresponding metabolites is important to understand gene expression. Here we report on a novel in vitro assay to study preQ(1) riboswitch aptamers upon binding of 7-aminomethyl-7-deazaguanine (preQ(1)). The assay is based on the ability of the preQ(1) aptamer to fold, upon ligand binding, into a pseudoknotted structure that is capable of stimulating -1 ribosomal frameshifting (-1 FS). Aptamers from three different species were found to induce between 7% and 20% of -1 FS in response to increasing preQ(1) levels, whereas preQ(1) analogues were 100-1000-fold less efficient. In depth mutational analysis of the Fusobacterium nucleatum aptamer recapitulates most of the structural details previously identified for preQ(1) aptamers from other bacteria by crystallography and/or NMR spectroscopy. In addition to providing insight into the role of individual nucleotides of the preQ(1) riboswitch aptamer in ligand binding, the presented system provides a valuable tool to screen small molecules against bacterial riboswitches in a eukaryotic background.
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Affiliation(s)
| | | | - Dirk Iwata-Reuyl
- Department of Chemistry, Portland State University, Portland, Oregon 97201,
United States
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Programmed -1 frameshifting efficiency correlates with RNA pseudoknot conformational plasticity, not resistance to mechanical unfolding. Proc Natl Acad Sci U S A 2012; 109:16167-72. [PMID: 22988073 DOI: 10.1073/pnas.1204114109] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Programmed -1 frameshifting, whereby the reading frame of a ribosome on messenger RNA is shifted in order to generate an alternate gene product, is often triggered by a pseudoknot structure in the mRNA in combination with an upstream slippery sequence. The efficiency of frameshifting varies widely for different sites, but the factors that determine frameshifting efficiency are not yet fully understood. Previous work has suggested that frameshifting efficiency is related to the resistance of the pseudoknot against mechanical unfolding. We tested this hypothesis by studying the mechanical properties of a panel of pseudoknots with frameshifting efficiencies ranging from 2% to 30%: four pseudoknots from retroviruses, two from luteoviruses, one from a coronavirus, and a nonframeshifting bacteriophage pseudoknot. Using optical tweezers to apply tension across the RNA, we measured the distribution of forces required to unfold each pseudoknot. We found that neither the average unfolding force, nor the unfolding kinetics, nor the parameters describing the energy landscape for mechanical unfolding of the pseudoknot (energy barrier height and distance to the transition state) could be correlated to frameshifting efficiency. These results indicate that the resistance of pseudoknots to mechanical unfolding is not a primary determinant of frameshifting efficiency. However, increased frameshifting efficiency was correlated with an increased tendency to form alternate, incompletely folded structures, suggesting a more complex picture of the role of the pseudoknot involving the conformational dynamics.
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Loakes D. Nucleotides and nucleic acids; oligo- and polynucleotides. ORGANOPHOSPHORUS CHEMISTRY 2012. [DOI: 10.1039/9781849734875-00169] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- David Loakes
- Medical Research Council Laboratory of Molecular Biology, Hills Road Cambridge CB2 2QH UK
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Gupta A, Rahman R, Li K, Gribskov M. Identifying complete RNA structural ensembles including pseudoknots. RNA Biol 2012; 9:187-99. [PMID: 22418849 DOI: 10.4161/rna.18386] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The close relationship between RNA structure and function underlines the significance of accurately predicting RNA structures from sequence information. Structural topologies such as pseudoknots are of particular interest due to their ubiquity and direct involvement in RNA function, but identifying pseudoknots is a computationally challenging problem and existing heuristic approaches usually perform poorly for RNA sequences of even a few hundred bases. We survey the performance of pseudoknot prediction methods on a data set of full-length RNA sequences representing varied sequence lengths, and biological RNA classes such as RNase P RNA, Group I Intron, tmRNA and tRNA. Pseudoknot prediction methods are compared with minimum free energy and suboptimal secondary structure prediction methods in terms of correct base-pairs, stems and pseudoknots and we find that the ensemble of suboptimal structure predictions succeeds in identifying correct structural elements in RNA that are usually missed in MFE and pseudoknot predictions. We propose a strategy to identify a comprehensive set of non-redundant stems in the suboptimal structure space of a RNA molecule by applying heuristics that reduce the structural redundancy of the predicted suboptimal structures by merging slightly varying stems that are predicted to form in local sequence regions. This reduced-redundancy set of structural elements consistently outperforms more specialized approaches.in data sets. Thus, the suboptimal folding space can be used to represent the structural diversity of an RNA molecule more comprehensively than optimal structure prediction approaches alone.
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Affiliation(s)
- Aditi Gupta
- Department of Biological Sciences; Purdue University; West Lafayette, IN, USA
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Wang K, Schmied WH, Chin JW. Reprogramming the genetic code: from triplet to quadruplet codes. Angew Chem Int Ed Engl 2012; 51:2288-97. [PMID: 22262408 DOI: 10.1002/anie.201105016] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Indexed: 11/10/2022]
Abstract
The genetic code of cells is near-universally triplet, and since many ribosomal mutations are lethal, changing the cellular ribosome to read nontriplet codes is challenging. Herein we review work on the incorporation of unnatural amino acids into proteins in response to quadruplet codons, and the creation of an orthogonal translation system in the cell that uses an evolved orthogonal ribosome to efficiently direct the incorporation of unnatural amino acids in response to quadruplet codons. Using this system multiple distinct unnatural amino acids have been incorporated and used to genetically program emergent properties into recombinant proteins. Extension of approaches to incorporate multiple unnatural amino acids may allow the combinatorial biosynthesis of materials and therapeutics, and drive investigations into whether life with additional genetically encoded polymers can evolve to perform functions that natural biological systems cannot.
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Affiliation(s)
- Kaihang Wang
- Medical Research Council Laboratory of Molecular Biology, Hills Rd, Cambridge, CB2 0QH UK
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Wang K, Schmied WH, Chin JW. Die Umprogrammierung des genetischen Codes: vom Triplett- zum Quadruplettcode. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201105016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yu CH, Noteborn MH, Pleij CWA, Olsthoorn RCL. Stem-loop structures can effectively substitute for an RNA pseudoknot in -1 ribosomal frameshifting. Nucleic Acids Res 2011; 39:8952-9. [PMID: 21803791 PMCID: PMC3203594 DOI: 10.1093/nar/gkr579] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
-1 Programmed ribosomal frameshifting (PRF) in synthesizing the gag-pro precursor polyprotein of Simian retrovirus type-1 (SRV-1) is stimulated by a classical H-type pseudoknot which forms an extended triple helix involving base-base and base-sugar interactions between loop and stem nucleotides. Recently, we showed that mutation of bases involved in triple helix formation affected frameshifting, again emphasizing the role of the triple helix in -1 PRF. Here, we investigated the efficiency of hairpins of similar base pair composition as the SRV-1 gag-pro pseudoknot. Although not capable of triple helix formation they proved worthy stimulators of frameshifting. Subsequent investigation of ∼30 different hairpin constructs revealed that next to thermodynamic stability, loop size and composition and stem irregularities can influence frameshifting. Interestingly, hairpins carrying the stable GAAA tetraloop were significantly less shifty than other hairpins, including those with a UUCG motif. The data are discussed in relation to natural shifty hairpins.
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Affiliation(s)
- Chien-Hung Yu
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
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Belew AT, Advani VM, Dinman JD. Endogenous ribosomal frameshift signals operate as mRNA destabilizing elements through at least two molecular pathways in yeast. Nucleic Acids Res 2010; 39:2799-808. [PMID: 21109528 PMCID: PMC3074144 DOI: 10.1093/nar/gkq1220] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Although first discovered in viruses, previous studies have identified operational −1 ribosomal frameshifting (−1 RF) signals in eukaryotic genomic sequences, and suggested a role in mRNA stability. Here, four yeast −1 RF signals are shown to promote significant mRNA destabilization through the nonsense mediated mRNA decay pathway (NMD), and genetic evidence is presented suggesting that they may also operate through the no-go decay pathway (NGD) as well. Yeast EST2 mRNA is highly unstable and contains up to five −1 RF signals. Ablation of the −1 RF signals or of NMD stabilizes this mRNA, and changes in −1 RF efficiency have opposing effects on the steady-state abundance of the EST2 mRNA. These results demonstrate that endogenous −1 RF signals function as mRNA destabilizing elements through at least two molecular pathways in yeast. Consistent with current evolutionary theory, phylogenetic analyses suggest that −1 RF signals are rapidly evolving cis-acting regulatory elements. Identification of high confidence −1 RF signals in ∼10% of genes in all eukaryotic genomes surveyed suggests that −1 RF is a broadly used post-transcriptional regulator of gene expression.
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Affiliation(s)
- Ashton T Belew
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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