1
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Gerling N, Mendez JA, Gomez E, Ruiz-Garcia J. The separation between mRNA-ends is more variable than expected. FEBS Open Bio 2024. [PMID: 39226224 DOI: 10.1002/2211-5463.13877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 07/29/2024] [Indexed: 09/05/2024] Open
Abstract
Effective circularization of mRNA molecules is a key step for the efficient initiation of translation. Research has shown that the intrinsic separation of the ends of mRNA molecules is rather small, suggesting that intramolecular arrangements could provide this effective circularization. Considering that the innate proximity of RNA ends might have important unknown biological implications, we aimed to determine whether the close proximity of the ends of mRNA molecules is a conserved feature across organisms and gain further insights into the functional effects of the proximity of RNA ends. To do so, we studied the secondary structure of 274 full native mRNA molecules from 17 different organisms to calculate the contour length (CL) of the external loop as an index of their end-to-end separation. Our computational predictions show bigger variations (from 0.59 to 31.8 nm) than previously reported and also than those observed in random sequences. Our results suggest that separations larger than 18.5 nm are not favored, whereas short separations could be related to phenotypical stability. Overall, our work implies the existence of a biological mechanism responsible for the increase in the observed variability, suggesting that the CL features of the exterior loop could be relevant for the initiation of translation and that a short CL could contribute to the stability of phenotypes.
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Affiliation(s)
- Nancy Gerling
- Institute of Physics, Biological Physics Laboratory, San Luis Potosi, Mexico
| | - J Alfredo Mendez
- Institute of Physics, Laboratory of Molecular Biophysics, San Luis Potosi, Mexico
| | - Eduardo Gomez
- Cold Atoms Laboratory, Institute of Physics, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | - Jaime Ruiz-Garcia
- Institute of Physics, Biological Physics Laboratory, San Luis Potosi, Mexico
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2
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Nissley AJ, Kamal TS, Cate JHD. Interactions between terminal ribosomal RNA helices stabilize the E. coli large ribosomal subunit. RNA (NEW YORK, N.Y.) 2023; 29:1500-1508. [PMID: 37419664 PMCID: PMC10578474 DOI: 10.1261/rna.079690.123] [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: 04/21/2023] [Accepted: 06/11/2023] [Indexed: 07/09/2023]
Abstract
The ribosome is a large ribonucleoprotein assembly that uses diverse and complex molecular interactions to maintain proper folding. In vivo assembled ribosomes have been isolated using MS2 tags installed in either the 16S or 23S ribosomal RNAs (rRNAs), to enable studies of ribosome structure and function in vitro. RNA tags in the Escherichia coli 50S subunit have commonly been inserted into an extended helix H98 in 23S rRNA, as this addition does not affect cellular growth or in vitro ribosome activity. Here, we find that E. coli 50S subunits with MS2 tags inserted in H98 are destabilized compared to wild-type (WT) 50S subunits. We identify the loss of RNA-RNA tertiary contacts that bridge helices H1, H94, and H98 as the cause of destabilization. Using cryogenic electron microscopy (cryo-EM), we show that this interaction is disrupted by the addition of the MS2 tag and can be restored through the insertion of a single adenosine in the extended H98 helix. This work establishes ways to improve MS2 tags in the 50S subunit that maintain ribosome stability and investigates a complex RNA tertiary structure that may be important for stability in various bacterial ribosomes.
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Affiliation(s)
- Amos J Nissley
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, USA
| | - Tammam S Kamal
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
| | - Jamie H D Cate
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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3
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Waldl M, Spicher T, Lorenz R, Beckmann IK, Hofacker IL, Löhneysen SV, Stadler PF. Local RNA folding revisited. J Bioinform Comput Biol 2023; 21:2350016. [PMID: 37522173 DOI: 10.1142/s0219720023500166] [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: 08/01/2023]
Abstract
Most of the functional RNA elements located within large transcripts are local. Local folding therefore serves a practically useful approximation to global structure prediction. Due to the sensitivity of RNA secondary structure prediction to the exact definition of sequence ends, accuracy can be increased by averaging local structure predictions over multiple, overlapping sequence windows. These averages can be computed efficiently by dynamic programming. Here we revisit the local folding problem, present a concise mathematical formalization that generalizes previous approaches and show that correct Boltzmann samples can be obtained by local stochastic backtracing in McCaskill's algorithms but not from local folding recursions. Corresponding new features are implemented in the ViennaRNA package to improve the support of local folding. Applications include the computation of maximum expected accuracy structures from RNAplfold data and a mutual information measure to quantify the sensitivity of individual sequence positions.
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Affiliation(s)
- Maria Waldl
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Wien, Austria
| | - Thomas Spicher
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Wien, Austria
| | - Ronny Lorenz
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Wien, Austria
| | - Irene K Beckmann
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Wien, Austria
| | - Ivo L Hofacker
- Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, 1090 Wien, Austria
| | - Sarah Von Löhneysen
- Institute of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, D-04107 Leipzig, Germany
| | - Peter F Stadler
- Institute of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, Härtelstraße 16-18, D-04107 Leipzig, Germany
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4
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Sun B, Kim H, Mello CC, Priess JR. The CERV protein of Cer1, a C. elegans LTR retrotransposon, is required for nuclear export of viral genomic RNA and can form giant nuclear rods. PLoS Genet 2023; 19:e1010804. [PMID: 37384599 PMCID: PMC10309623 DOI: 10.1371/journal.pgen.1010804] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 05/31/2023] [Indexed: 07/01/2023] Open
Abstract
Retroviruses and closely related LTR retrotransposons export full-length, unspliced genomic RNA (gRNA) for packaging into virions and to serve as the mRNA encoding GAG and POL polyproteins. Because gRNA often includes splice acceptor and donor sequences used to splice viral mRNAs, retroelements must overcome host mechanisms that retain intron-containing RNAs in the nucleus. Here we examine gRNA expression in Cer1, an LTR retrotransposon in C. elegans which somehow avoids silencing and is highly expressed in germ cells. Newly exported Cer1 gRNA associates rapidly with the Cer1 GAG protein, which has structural similarity with retroviral GAG proteins. gRNA export requires CERV (C. elegans regulator of viral expression), a novel protein encoded by a spliced Cer1 mRNA. CERV phosphorylation at S214 is essential for gRNA export, and phosphorylated CERV colocalizes with nuclear gRNA at presumptive sites of transcription. By electron microscopy, tagged CERV proteins surround clusters of distinct, linear fibrils that likely represent gRNA molecules. Single fibrils, or groups of aligned fibrils, also localize near nuclear pores. During the C. elegans self-fertile period, when hermaphrodites fertilize oocytes with their own sperm, CERV concentrates in two nuclear foci that are coincident with gRNA. However, as hermaphrodites cease self-fertilization, and can only produce cross-progeny, CERV undergoes a remarkable transition to form giant nuclear rods or cylinders that can be up to 5 microns in length. We propose a novel mechanism of rod formation, in which stage-specific changes in the nucleolus induce CERV to localize to the nucleolar periphery in flattened streaks of protein and gRNA; these streaks then roll up into cylinders. The rods are a widespread feature of Cer1 in wild strains of C. elegans, but their function is not known and might be limited to cross-progeny. We speculate that the adaptive strategy Cer1 uses for the identical self-progeny of a host hermaphrodite might differ for heterozygous cross-progeny sired by males. For example, mating introduces male chromosomes which can have different, or no, Cer1 elements.
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Affiliation(s)
- Bing Sun
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester,United States of America
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Haram Kim
- Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Craig C. Mello
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester,United States of America
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - James R. Priess
- Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
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5
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Single-molecule visualization of mRNA circularization during translation. Exp Mol Med 2023; 55:283-289. [PMID: 36720916 PMCID: PMC9981743 DOI: 10.1038/s12276-023-00933-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/04/2022] [Accepted: 12/04/2022] [Indexed: 02/02/2023] Open
Abstract
Translation is mediated by precisely orchestrated sequential interactions among translation initiation components, mRNA, and ribosomes. Biochemical, structural, and genetic techniques have revealed the fundamental mechanism that determines what occurs and when, where and in what order. Most mRNAs are circularized via the eIF4E-eIF4G-PABP interaction, which stabilizes mRNAs and enhances translation by recycling ribosomes. However, studies using single-molecule fluorescence imaging have allowed for the visualization of complex data that opposes the traditional "functional circularization" theory. Here, we briefly introduce single-molecule techniques applied to studies on mRNA circularization and describe the results of in vitro and live-cell imaging. Finally, we discuss relevant insights and questions gained from single-molecule research related to translation.
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6
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Zhang H, Zhang L, Liu K, Li S, Mathews DH, Huang L. Linear-Time Algorithms for RNA Structure Prediction. Methods Mol Biol 2023; 2586:15-34. [PMID: 36705896 DOI: 10.1007/978-1-0716-2768-6_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
RNA secondary structure prediction is widely used to understand RNA function. Existing dynamic programming-based algorithms, both the classical minimum free energy (MFE) methods and partition function methods, suffer from a major limitation: their runtimes scale cubically with the RNA length, and this slowness limits their use in genome-wide applications. Inspired by incremental parsing for context-free grammars in computational linguistics, we designed linear-time heuristic algorithms, LinearFold and LinearPartition, to approximate the MFE structure, partition function and base pairing probabilities. These programs are orders of magnitude faster than Vienna RNAfold and CONTRAfold on long sequences. More interestingly, LinearFold and LinearPartition lead to more accurate predictions on the longest sequence families for which the structures are well established (16S and 23S Ribosomal RNAs), as well as improved accuracies for long-range base pairs (500 + nucleotides apart). This chapter provides protocols for using LinearFold and LinearPartition for secondary structure prediction.
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Affiliation(s)
- He Zhang
- Baidu Research USA, Sunnyvale, CA, USA.,School of Electrical Engineering & Computer Science, Oregon State University, Corvallis, OR, USA
| | - Liang Zhang
- Baidu Research USA, Sunnyvale, CA, USA.,School of Electrical Engineering & Computer Science, Oregon State University, Corvallis, OR, USA
| | - Kaibo Liu
- Baidu Research USA, Sunnyvale, CA, USA
| | - Sizhen Li
- School of Electrical Engineering & Computer Science, Oregon State University, Corvallis, OR, USA
| | - David H Mathews
- Dept. of Biochemistry & Biophysics, Center for RNA Biology, Rochester, NY, USA.,Dept. of Biostatistics & Computational Biology, University of Rochester Medical Center, Rochester, NY, USA
| | - Liang Huang
- School of Electrical Engineering & Computer Science, Oregon State University, Corvallis, OR, USA.
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7
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Lai WJC, Zhu M, Belinite M, Ballard G, Mathews DH, Ermolenko DN. Intrinsically Unstructured Sequences in the mRNA 3' UTR Reduce the Ability of Poly(A) Tail to Enhance Translation. J Mol Biol 2022; 434:167877. [PMID: 36368412 PMCID: PMC9750134 DOI: 10.1016/j.jmb.2022.167877] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 09/27/2022] [Accepted: 11/01/2022] [Indexed: 11/09/2022]
Abstract
The 5' cap and 3' poly(A) tail of mRNA are known to synergistically stimulate translation initiation via the formation of the cap•eIF4E•eIF4G•PABP•poly(A) complex. Most mRNA sequences have an intrinsic propensity to fold into extensive intramolecular secondary structures that result in short end-to-end distances. The inherent compactness of mRNAs might stabilize the cap•eIF4E•eIF4G•PABP•poly(A) complex and enhance cap-poly(A) translational synergy. Here, we test this hypothesis by introducing intrinsically unstructured sequences into the 5' or 3' UTRs of model mRNAs. We found that the introduction of unstructured sequences into the 3' UTR, but not the 5' UTR, decreases mRNA translation in cell-free wheat germ and yeast extracts without affecting mRNA stability. The observed reduction in protein synthesis results from the diminished ability of the poly(A) tail to stimulate translation. These results suggest that base pair formation by the 3' UTR enhances the cap-poly(A) synergy in translation initiation.
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Affiliation(s)
- Wan-Jung C Lai
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, United States
| | - Mingyi Zhu
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, United States
| | - Margarita Belinite
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, United States
| | - Gregory Ballard
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, United States
| | - David H Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, United States
| | - Dmitri N Ermolenko
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, United States.
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8
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Kim B, Park Y, Hwang HJ, Chang J, Kim YK, Lee JB. Single polysome analysis of mRNP. Biochem Biophys Res Commun 2022; 618:73-78. [PMID: 35716598 DOI: 10.1016/j.bbrc.2022.06.017] [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: 05/27/2022] [Accepted: 06/06/2022] [Indexed: 11/17/2022]
Abstract
Eukaryotic translation is a complex process that involves the interplay of various translation factors to convert genetic information into a specific amino acid chain. According to an elegant model of eukaryotic translation initiation, the 3' poly(A) tail of an mRNA, which is occupied by poly(A)-binding proteins (PABPs), communicates with the 5'-cap bound by eIF4E to enhance translation. Although the circularization of mRNA resulting from the communication is widely understood, it has yet to be directly observed. To explore mRNA circularization in translation, we analyzed the level of colocalization of eIF4E, eIF4G, and PABP on individual mRNAs in polysomal and subpolysomal fractions using single polysome analysis. Our results show that the three tested proteins barely coexist in mRNA in either polysomal or subpolysomal fractions, implying that the closed-loop structure generated by the communication between eIF4E, eIF4G, and PAPB may be transient during translation.
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Affiliation(s)
- Byungju Kim
- Department of Physics, Pohang University of Science & Technology (POSTECH), Pohang, 37673, South Korea
| | - Yeonkyoung Park
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul, 02841, South Korea; School of Life Sciences, Korea University, Seoul, 02841, South Korea
| | - Hyun Jung Hwang
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul, 02841, South Korea; School of Life Sciences, Korea University, Seoul, 02841, South Korea
| | - Jeeyoon Chang
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul, 02841, South Korea; School of Life Sciences, Korea University, Seoul, 02841, South Korea
| | - Yoon Ki Kim
- Creative Research Initiatives Center for Molecular Biology of Translation, Korea University, Seoul, 02841, South Korea; School of Life Sciences, Korea University, Seoul, 02841, South Korea.
| | - Jong-Bong Lee
- Department of Physics, Pohang University of Science & Technology (POSTECH), Pohang, 37673, South Korea; School of Interdisciplinary Bioscience & Bioengineering, POSTECH, Pohang, 37673, South Korea.
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9
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Biziaev NS, Egorova TV, Alkalaeva EZ. Dynamics of Eukaryotic mRNA Structure during Translation. Mol Biol 2022. [DOI: 10.1134/s0026893322030037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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10
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Abstract
Recent events have pushed RNA research into the spotlight. Continued discoveries of RNA with unexpected diverse functions in healthy and diseased cells, such as the role of RNA as both the source and countermeasure to a severe acute respiratory syndrome coronavirus 2 infection, are igniting a new passion for understanding this functionally and structurally versatile molecule. Although RNA structure is key to function, many foundational characteristics of RNA structure are misunderstood, and the default state of RNA is often thought of and depicted as a single floppy strand. The purpose of this perspective is to help adjust mental models, equipping the community to better use the fundamental aspects of RNA structural information in new mechanistic models, enhance experimental design to test these models, and refine data interpretation. We discuss six core observations focused on the inherent nature of RNA structure and how to incorporate these characteristics to better understand RNA structure. We also offer some ideas for future efforts to make validated RNA structural information available and readily used by all researchers.
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Affiliation(s)
- Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, School of Medicine, Aurora, CO 80045
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, CO 80045
| | - Jeffrey S. Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, School of Medicine, Aurora, CO 80045
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, CO 80045
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11
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Lin X, Fonseca MAS, Breunig JJ, Corona RI, Lawrenson K. In vivo discovery of RNA proximal proteins via proximity-dependent biotinylation. RNA Biol 2021; 18:2203-2217. [PMID: 34006179 PMCID: PMC8648264 DOI: 10.1080/15476286.2021.1917215] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/16/2021] [Accepted: 04/10/2021] [Indexed: 12/12/2022] Open
Abstract
RNA molecules function as messenger RNAs (mRNAs) that encode proteins and noncoding transcripts that serve as adaptor molecules, structural components, and regulators of genome organization and gene expression. Their function and regulation are largely mediated by RNA binding proteins (RBPs). Here we present RNA proximity labelling (RPL), an RNA-centric method comprising the endonuclease-deficient Type VI CRISPR-Cas protein dCas13b fused to engineered ascorbate peroxidase APEX2. RPL discovers target RNA proximal proteins in vivo via proximity-based biotinylation. RPL applied to U1 identified proteins involved in both U1 canonical and noncanonical functions. Profiling of poly(A) tail proximal proteins uncovered expected categories of RBPs and provided additional evidence for 5'-3' proximity and unexplored subcellular localizations of poly(A)+ RNA. Our results suggest that RPL allows rapid identification of target RNA binding proteins in native cellular contexts, and is expected to pave the way for discovery of novel RNA-protein interactions important for health and disease.
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Affiliation(s)
- Xianzhi Lin
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Marcos A. S. Fonseca
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Joshua J. Breunig
- Cedars-Sinai Medical Center, Board of Governors Regenerative Medicine Institute, Los Angeles, CA, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Cedars-Sinai Medical Center, Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Rosario I. Corona
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Kate Lawrenson
- Cedars-Sinai Medical Center, Women’s Cancer Research Program at Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Cedars-Sinai Medical Center, Center for Bioinformatics and Functional Genomics, Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA, USA
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12
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Hernández-Adame PL, Meza U, Rodríguez-Menchaca AA, Sánchez-Armass S, Ruiz-García J, Gomez E. Determination of the size of lipid rafts studied through single-molecule FRET simulations. Biophys J 2021; 120:2287-2295. [PMID: 33864789 DOI: 10.1016/j.bpj.2021.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/16/2021] [Accepted: 04/08/2021] [Indexed: 11/16/2022] Open
Abstract
Fluorescence resonance energy transfer (FRET) is a high-resolution technique that allows the characterization of spatial and temporal properties of biological structures and mechanisms. In this work, we developed an in silico single-molecule FRET methodology to study the dynamics of fluorophores inside lipid rafts. We monitored the fluorescence of a single acceptor molecule in the presence of several donor molecules. By looking at the average fluorescence, we selected events with single acceptor and donor molecules, and we used them to determine the raft size in the range of 5-16 nm. We conclude that our method is robust and insensitive to variations in the diffusion coefficient, donor density, or selected fluorescence threshold.
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Affiliation(s)
| | - Ulises Meza
- Department of Physiology and Biophysics, School of Medicine, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | - Aldo A Rodríguez-Menchaca
- Department of Physiology and Biophysics, School of Medicine, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | - Sergio Sánchez-Armass
- Department of Physiology and Biophysics, School of Medicine, Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico
| | - Jaime Ruiz-García
- Biological Physics Laboratory, Physics Institute, San Luis Potosí, Mexico.
| | - Eduardo Gomez
- Biological Physics Laboratory, Physics Institute, San Luis Potosí, Mexico.
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13
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Subcellular Architecture of the xyl Gene Expression Flow of the TOL Catabolic Plasmid of Pseudomonas putida mt-2. mBio 2021; 12:mBio.03685-20. [PMID: 33622725 PMCID: PMC8545136 DOI: 10.1128/mbio.03685-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Despite intensive research on the biochemical and regulatory features of the archetypal catabolic TOL system borne by pWW0 of Pseudomonas putida strain mt-2, the physical arrangement and tridimensional logic of the xyl gene expression flow remains unknown. In this work, the spatial distribution of specific xyl mRNAs with respect to the host nucleoid, the TOL plasmid, and the ribosomal pool has been investigated. In situ hybridization of target transcripts with fluorescent oligonucleotide probes revealed that xyl mRNAs cluster in discrete foci, adjacent but clearly separated from the TOL plasmid and the cell nucleoid. Also, they colocalize with ribosome-rich domains of the intracellular milieu. This arrangement was maintained even when the xyl genes were artificially relocated to different chromosomal locations. The same held true when genes were expressed through a heterologous T7 polymerase-based system, which likewise led to mRNA foci outside the DNA. In contrast, rifampin treatment, known to ease crowding, blurred the confinement of xyl transcripts. This suggested that xyl mRNAs exit from their initiation sites to move to ribosome-rich points for translation—rather than being translated coupled to transcription. Moreover, the results suggest the distinct subcellular motion of xyl mRNAs results from both innate properties of the sequences and the physical forces that keep the ribosomal pool away from the nucleoid in P. putida. This scenario is discussed within the background of current knowledge on the three-dimensional organization of the gene expression flow in other bacteria and the environmental lifestyle of this soil microorganism.
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14
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Çetin B, Song GJ, O'Leary SE. Heterogeneous Dynamics of Protein-RNA Interactions across Transcriptome-Derived Messenger RNA Populations. J Am Chem Soc 2020; 142:21249-21253. [PMID: 33315378 DOI: 10.1021/jacs.0c09841] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dynamic RNA-protein interactions underpin numerous molecular control mechanisms in biology. However, relatively little is known about the kinetic landscape of protein interactions with full-length RNAs. The extent to which interaction kinetics vary for the same RNA element across the transcriptome and the molecular determinants of variability therefore remain poorly defined. Moreover, it is unclear how one protein-RNA interaction might be transduced by RNA to kinetically impact a second. We report a parallelized, real-time single-molecule fluorescence assay for protein interaction kinetics on eukaryotic mRNA populations obtained from cells. We observed ∼100-fold heterogeneity for interactions of the translation initiation factor eIF4E with the universal mRNA 5' cap structure, dominated by steric effects on barrier-height variability for association. We also found that an RNA helicase, eIF4A, independently accelerated eIF4E-cap association. These data support a kinetic mechanism for how mRNA can determine the sensitivity of its translation to reduction in cellular eIF4E concentrations. They also support the view that global RNA structure significantly modulates protein-RNA interaction dynamics and can facilitate real-time communication between protein interactions at distinct sites.
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Affiliation(s)
- Burak Çetin
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California, Riverside, California 92521, United States
| | - Gary J Song
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Seán E O'Leary
- Department of Biochemistry, University of California, Riverside, California 92521, United States
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15
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Oh I, Lee H, Kim TW, Kim CW, Jun S, Kim C, Choi EH, Rhee YM, Kim J, Jang W, Ihee H. Enhancement of Energy Transfer Efficiency with Structural Control of Multichromophore Light-Harvesting Assembly. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2001623. [PMID: 33101863 PMCID: PMC7578888 DOI: 10.1002/advs.202001623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Multichromophore systems (MCSs) are envisioned as building blocks of molecular optoelectronic devices. While it is important to understand the characteristics of energy transfer in MCSs, the effect of multiple donors on energy transfer has not been understood completely, mainly due to the lack of a platform to investigate such an effect systematically. Here, a systematic study on how the number of donors (n D) and interchromophore distances affect the efficiency of energy transfer (η FRET) is presented. Specifically, η FRET is calculated for a series of model MCSs using simulations, a series of multiporphyrin dendrimers with systematic variation of n D and interdonor distances is synthesized, and η FRETs of those dendrimers using transient absorption spectroscopy are measured. The simulations predict η FRET in the multiporphyrin dendrimers well. In particular, it is found that η FRET is enhanced by donor-to-donor energy transfer only when structural heterogeneity exists in an MCS, and the relationships between the η FRET enhancement and the structural parameters of the MCS are revealed.
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Affiliation(s)
- Inhwan Oh
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Nanomaterials and Chemical ReactionsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
- KI for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Hosoowi Lee
- Department of ChemistryCollege of ScienceYonsei UniversitySeoul120‐749Republic of Korea
| | - Tae Wu Kim
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Nanomaterials and Chemical ReactionsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
- KI for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Chang Woo Kim
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Sunhong Jun
- Center for Nanomaterials and Chemical ReactionsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
| | - Changwon Kim
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Nanomaterials and Chemical ReactionsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
- KI for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Eun Hyuk Choi
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Nanomaterials and Chemical ReactionsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
- KI for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Young Min Rhee
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Jeongho Kim
- Department of ChemistryInha UniversityIncheon22212Republic of Korea
| | - Woo‐Dong Jang
- Department of ChemistryCollege of ScienceYonsei UniversitySeoul120‐749Republic of Korea
| | - Hyotcherl Ihee
- Department of ChemistryKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
- Center for Nanomaterials and Chemical ReactionsInstitute for Basic Science (IBS)Daejeon34141Republic of Korea
- KI for the BioCenturyKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
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16
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Ermolenko DN, Mathews DH. Making ends meet: New functions of mRNA secondary structure. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1611. [PMID: 32597020 DOI: 10.1002/wrna.1611] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/19/2020] [Accepted: 05/19/2020] [Indexed: 11/10/2022]
Abstract
The 5' cap and 3' poly(A) tail of mRNA are known to synergistically regulate mRNA translation and stability. Recent computational and experimental studies revealed that both protein-coding and non-coding RNAs will fold with extensive intramolecular secondary structure, which will result in close distances between the sequence ends. This proximity of the ends is a sequence-independent, universal property of most RNAs. Only low-complexity sequences without guanosines are without secondary structure and exhibit end-to-end distances expected for RNA random coils. The innate proximity of RNA ends might have important biological implications that remain unexplored. In particular, the inherent compactness of mRNA might regulate translation initiation by facilitating the formation of protein complexes that bridge mRNA 5' and 3' ends. Additionally, the proximity of mRNA ends might mediate coupling of 3' deadenylation to 5' end mRNA decay. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems Translation > Translation Regulation.
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Affiliation(s)
- Dmitri N Ermolenko
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | - David H Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
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17
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Kluge F, Götze M, Wahle E. Establishment of 5'-3' interactions in mRNA independent of a continuous ribose-phosphate backbone. RNA (NEW YORK, N.Y.) 2020; 26:613-628. [PMID: 32111664 PMCID: PMC7161349 DOI: 10.1261/rna.073759.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 02/24/2020] [Indexed: 06/10/2023]
Abstract
Functions of eukaryotic mRNAs are characterized by intramolecular interactions between their ends. We have addressed the question whether 5' and 3' ends meet by diffusion-controlled encounter "through solution" or by a mechanism involving the RNA backbone. For this purpose, we used a translation system derived from Drosophila embryos that displays two types of 5'-3' interactions: Cap-dependent translation initiation is stimulated by the poly(A) tail and inhibited by Smaug recognition elements (SREs) in the 3' UTR. Chimeric RNAs were made consisting of one RNA molecule carrying a luciferase coding sequence and a second molecule containing SREs and a poly(A) tail; the two were connected via a protein linker. The poly(A) tail stimulated translation of such chimeras even when disruption of the RNA backbone was combined with an inversion of the 5'-3' polarity between the open reading frame and poly(A) segment. Stimulation by the poly(A) tail also decreased with increasing RNA length. Both observations suggest that contacts between the poly(A) tail and the 5' end are established through solution, independently of the RNA backbone. In the same chimeric constructs, SRE-dependent inhibition of translation was also insensitive to disruption of the RNA backbone. Thus, tracking of the backbone is not involved in the repression of cap-dependent initiation. However, SRE-dependent repression was insensitive to mRNA length, suggesting that the contact between the SREs in the 3' UTR and the 5' end of the RNA might be established in a manner that differs from the contact between the poly(A) tail and the cap.
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Affiliation(s)
- Florian Kluge
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Michael Götze
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
| | - Elmar Wahle
- Institute of Biochemistry and Biotechnology and Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, 06099 Halle, Germany
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18
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Abstract
The proper regulation of mRNA processing, localization, translation, and degradation occurs on mRNPs. However, the global principles of mRNP organization are poorly understood. We utilize the limited, but existing, information available to present a speculative synthesis of mRNP organization with the following key points. First, mRNPs form a compacted structure due to the inherent folding of RNA. Second, the ribosome is the principal mechanism by which mRNA regions are partially decompacted. Third, mRNPs are 50%-80% protein by weight, consistent with proteins modulating mRNP organization, but also suggesting the majority of mRNA sequences are not directly interacting with RNA-binding proteins. Finally, the ratio of mRNA-binding proteins to mRNAs is higher in the nucleus to allow effective RNA processing and limit the potential for nuclear RNA based aggregation. This synthesis of mRNP understanding provides a model for mRNP biogenesis, structure, and regulation with multiple implications.
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Affiliation(s)
- Anthony Khong
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Roy Parker
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
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19
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Huang L, Zhang H, Deng D, Zhao K, Liu K, Hendrix DA, Mathews DH. LinearFold: linear-time approximate RNA folding by 5'-to-3' dynamic programming and beam search. Bioinformatics 2019; 35:i295-i304. [PMID: 31510672 PMCID: PMC6681470 DOI: 10.1093/bioinformatics/btz375] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
MOTIVATION Predicting the secondary structure of an ribonucleic acid (RNA) sequence is useful in many applications. Existing algorithms [based on dynamic programming] suffer from a major limitation: their runtimes scale cubically with the RNA length, and this slowness limits their use in genome-wide applications. RESULTS We present a novel alternative O(n3)-time dynamic programming algorithm for RNA folding that is amenable to heuristics that make it run in O(n) time and O(n) space, while producing a high-quality approximation to the optimal solution. Inspired by incremental parsing for context-free grammars in computational linguistics, our alternative dynamic programming algorithm scans the sequence in a left-to-right (5'-to-3') direction rather than in a bottom-up fashion, which allows us to employ the effective beam pruning heuristic. Our work, though inexact, is the first RNA folding algorithm to achieve linear runtime (and linear space) without imposing constraints on the output structure. Surprisingly, our approximate search results in even higher overall accuracy on a diverse database of sequences with known structures. More interestingly, it leads to significantly more accurate predictions on the longest sequence families in that database (16S and 23S Ribosomal RNAs), as well as improved accuracies for long-range base pairs (500+ nucleotides apart), both of which are well known to be challenging for the current models. AVAILABILITY AND IMPLEMENTATION Our source code is available at https://github.com/LinearFold/LinearFold, and our webserver is at http://linearfold.org (sequence limit: 100 000nt). SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Liang Huang
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
- Baidu Research USA, Sunnyvale, CA, USA
| | - He Zhang
- Baidu Research USA, Sunnyvale, CA, USA
| | - Dezhong Deng
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | - Kai Zhao
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
| | - Kaibo Liu
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
- Baidu Research USA, Sunnyvale, CA, USA
| | - David A Hendrix
- School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR, USA
- Department of Biochemistry & Biophysics, Oregon State University, University of Rochester Medical Center, Rochester, NY, USA
| | - David H Mathews
- Department of Biochemistry & Biophysics, University of Rochester Medical Center, Rochester, NY, USA
- Center for RNA Biology, University of Rochester Medical Center, Rochester, NY, USA
- Department of Biostatistics & Computational Biology, University of Rochester Medical Center, Rochester, NY, USA
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20
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Abstract
In eukaryotes, the separation of translation from transcription by the nuclear envelope enables mRNA modifications such as capping, splicing, and polyadenylation. These modifications are mediated by a spectrum of ribonuclear proteins that associate with preRNA transcripts, coordinating the different steps and coupling them to nuclear export, ensuring that only mature transcripts reach the cytoplasmic translation machinery. Although the components of this machinery have been identified and considerable functional insight has been achieved, a number of questions remain outstanding about mRNA nuclear export and how it is integrated into the nuclear phase of the gene expression pathway. Nuclear export factors mediate mRNA transit through nuclear pores to the cytoplasm, after which these factors are removed from the mRNA, preventing transcripts from returning to the nucleus. However, as outlined in this review, several aspects of the mechanism by which transport factor binding and release are mediated remain unclear, as are the roles of accessory nuclear components in these processes. Moreover, the mechanisms by which completion of mRNA splicing and polyadenylation are recognized, together with how they are coordinated with nuclear export, also remain only partially characterized. One attractive hypothesis is that dissociating poly(A) polymerase from the cleavage and polyadenylation machinery could signal completion of mRNA maturation and thereby provide a mechanism for initiating nuclear export. The impressive array of genetic, molecular, cellular, and structural data that has been generated about these systems now provides many of the tools needed to define the precise mechanisms involved in these processes and how they are integrated.
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Affiliation(s)
- Murray Stewart
- From the MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, United Kingdom
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21
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Vicens Q, Kieft JS, Rissland OS. Revisiting the Closed-Loop Model and the Nature of mRNA 5'-3' Communication. Mol Cell 2018; 72:805-812. [PMID: 30526871 PMCID: PMC6294470 DOI: 10.1016/j.molcel.2018.10.047] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/08/2018] [Accepted: 10/30/2018] [Indexed: 12/28/2022]
Abstract
Communication between the 5' and 3' ends of mature eukaryotic mRNAs lies at the heart of gene regulation, likely arising at the same time as the eukaryotic lineage itself. Our view of how and why it occurs has been shaped by elegant experiments that led to nearly universal acceptance of the "closed-loop model." However, new observations suggest that this classic model needs to be reexamined, revised, and expanded. Here, we address fundamental questions about the closed-loop model and discuss how a growing understanding of mRNA structure, dynamics, and intermolecular interactions presents new experimental opportunities. We anticipate that the application of emerging methods will lead to expanded models that include the role of intrinsic mRNA structure and quantitative dynamic descriptions of 5'-3' proximity linked to the functional status of an mRNA and will better reflect the messy realities of the crowded and rapidly changing cellular environment.
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Affiliation(s)
- Quentin Vicens
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA.
| | - Olivia S Rissland
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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22
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Adivarahan S, Livingston N, Nicholson B, Rahman S, Wu B, Rissland OS, Zenklusen D. Spatial Organization of Single mRNPs at Different Stages of the Gene Expression Pathway. Mol Cell 2018; 72:727-738.e5. [PMID: 30415950 PMCID: PMC6592633 DOI: 10.1016/j.molcel.2018.10.010] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/24/2018] [Accepted: 10/04/2018] [Indexed: 12/21/2022]
Abstract
mRNAs form ribonucleoprotein complexes (mRNPs) by association with proteins that are crucial for mRNA metabolism. While the mRNP proteome has been well characterized, little is known about mRNP organization. Using a single-molecule approach, we show that mRNA conformation changes depending on its cellular localization and translational state. Compared to nuclear mRNPs and lncRNPs, association with ribosomes decompacts individual mRNAs, while pharmacologically dissociating ribosomes or sequestering them into stress granules leads to increased compaction. Moreover, translating mRNAs rarely show co-localized 5' and 3' ends, indicating either that mRNAs are not translated in a closed-loop configuration, or that mRNA circularization is transient, suggesting that a stable closed-loop conformation is not a universal state for all translating mRNAs.
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Affiliation(s)
- Srivathsan Adivarahan
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Nathan Livingston
- The Department of Biophysics and Biophysical Chemistry, the Solomon Snyder Department of Neuroscience, Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA
| | - Beth Nicholson
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Samir Rahman
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Bin Wu
- The Department of Biophysics and Biophysical Chemistry, the Solomon Snyder Department of Neuroscience, Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, MD 21224, USA
| | - Olivia S Rissland
- Molecular Medicine Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Daniel Zenklusen
- Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada.
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23
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mRNAs and lncRNAs intrinsically form secondary structures with short end-to-end distances. Nat Commun 2018; 9:4328. [PMID: 30337527 PMCID: PMC6193969 DOI: 10.1038/s41467-018-06792-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 09/20/2018] [Indexed: 12/17/2022] Open
Abstract
The 5' and 3' termini of RNA play important roles in many cellular processes. Using Förster resonance energy transfer (FRET), we show that mRNAs and lncRNAs have an intrinsic propensity to fold in the absence of proteins into structures in which the 5' end and 3' end are ≤7 nm apart irrespective of mRNA length. Computational estimates suggest that the inherent proximity of the ends is a universal property of most mRNA and lncRNA sequences. Only guanosine-depleted RNA sequences with low sequence complexity are unstructured and exhibit end-to-end distances expected for the random coil conformation of RNA. While the biological implications remain to be explored, short end-to-end distances could facilitate the binding of protein factors that regulate translation initiation by bridging mRNA 5' and 3' ends. Furthermore, our studies provide the basis for measuring, computing and manipulating end-to-end distances and secondary structure in RNA in research and biotechnology.
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24
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Rogers DW, Böttcher MA, Traulsen A, Greig D. Ribosome reinitiation can explain length-dependent translation of messenger RNA. PLoS Comput Biol 2017; 13:e1005592. [PMID: 28598992 PMCID: PMC5482490 DOI: 10.1371/journal.pcbi.1005592] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/23/2017] [Accepted: 05/25/2017] [Indexed: 12/21/2022] Open
Abstract
Models of mRNA translation usually presume that transcripts are linear; upon reaching the end of a transcript each terminating ribosome returns to the cytoplasmic pool before initiating anew on a different transcript. A consequence of linear models is that faster translation of a given mRNA is unlikely to generate more of the encoded protein, particularly at low ribosome availability. Recent evidence indicates that eukaryotic mRNAs are circularized, potentially allowing terminating ribosomes to preferentially reinitiate on the same transcript. Here we model the effect of ribosome reinitiation on translation and show that, at high levels of reinitiation, protein synthesis rates are dominated by the time required to translate a given transcript. Our model provides a simple mechanistic explanation for many previously enigmatic features of eukaryotic translation, including the negative correlation of both ribosome densities and protein abundance on transcript length, the importance of codon usage in determining protein synthesis rates, and the negative correlation between transcript length and both codon adaptation and 5' mRNA folding energies. In contrast to linear models where translation is largely limited by initiation rates, our model reveals that all three stages of translation-initiation, elongation, and termination/reinitiation-determine protein synthesis rates even at low ribosome availability.
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Affiliation(s)
- David W. Rogers
- Experimental Evolution Research Group, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany
- * E-mail:
| | - Marvin A. Böttcher
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Arne Traulsen
- Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Duncan Greig
- Experimental Evolution Research Group, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Department of Genetics, Evolution, and Environment, University College London, London, United Kingdom
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25
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Liu ZY, Li XF, Jiang T, Deng YQ, Ye Q, Zhao H, Yu JY, Qin CF. Viral RNA switch mediates the dynamic control of flavivirus replicase recruitment by genome cyclization. eLife 2016; 5. [PMID: 27692070 PMCID: PMC5101012 DOI: 10.7554/elife.17636] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 09/30/2016] [Indexed: 12/23/2022] Open
Abstract
Viral replicase recruitment and long-range RNA interactions are essential for RNA virus replication, yet the mechanism of their interplay remains elusive. Flaviviruses include numerous important human pathogens, e.g., dengue virus (DENV) and Zika virus (ZIKV). Here, we revealed a highly conserved, conformation-tunable cis-acting element named 5′-UAR-flanking stem (UFS) in the flavivirus genomic 5′ terminus. We demonstrated that the UFS was critical for efficient NS5 recruitment and viral RNA synthesis in different flaviviruses. Interestingly, stabilization of the DENV UFS impaired both genome cyclization and vRNA replication. Moreover, the UFS unwound in response to genome cyclization, leading to the decreased affinity of NS5 for the viral 5′ end. Thus, we propose that the UFS is switched by genome cyclization to regulate dynamic RdRp binding for vRNA replication. This study demonstrates that the UFS enables communication between flavivirus genome cyclization and RdRp recruitment, highlighting the presence of switch-like mechanisms among RNA viruses. DOI:http://dx.doi.org/10.7554/eLife.17636.001 Flaviviruses include a large family of viruses that are harmful to human health, such as dengue virus, West Nile virus and Zika virus. Understanding the details of the life cycle of these viruses is important for better controlling and treating the diseases that they cause. The genetic information of flaviviruses is stored in single-stranded molecules of RNA. To form new copies of a virus, the RNA must be replicated in a process that involves two critical steps. First, an enzyme called viral RNA polymerase NS5 must be recruited to a specific end of the RNA strand (known as the 5′ end). Then, the ends of the RNA strand bind together to form a circular loop. However, little is known about whether these two processes are linked, or how they are regulated. Using bioinformatics, biochemical and reverse genetics approaches, Liu et al. have now identified a new section of RNA in the 5′ end of the flavivirus RNA, named the 5′-UAR-flanking stem (or UFS for short), which is critical for viral replication. The UFS plays an important role in efficiently recruiting the NS5 viral RNA polymerase to the 5′ end of the flavivirus RNA. After the RNA forms a circle, the UFS unwinds. This makes the NS5 polymerase less likely to bind to the 5′ end of the RNA. Stabilizing the structure of the UFS impairs the ability of the RNA strand to form a circle, and hence reduces the ability of the RNA to replicate. Thus, the UFS links and enables communication between the processes that form the flavivirus RNA into a circle and that recruit the viral RNA polymerase to the RNA. The structural basis of the interaction between the flavivirus RNA 5′ end, including the UFS element, and the viral RNA polymerase now deserves further investigation. It will be also important to explore whether other types of viruses regulate their replication via a similar mechanism. DOI:http://dx.doi.org/10.7554/eLife.17636.002
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Affiliation(s)
- Zhong-Yu Liu
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Xiao-Feng Li
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Tao Jiang
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Yong-Qiang Deng
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
| | - Qing Ye
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Hui Zhao
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Jiu-Yang Yu
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Cheng-Feng Qin
- Department of Virology, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,State Key Laboratory of Pathogen and Biosecurity, Beijing, China
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