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Warner BR, Fredrick K. Contribution of an alternative 16S rRNA helix to biogenesis of the 30S subunit of the ribosome. RNA 2024:rna.079960.124. [PMID: 38570183 DOI: 10.1261/rna.079960.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/23/2024] [Indexed: 04/05/2024]
Abstract
30S subunits become inactive upon exposure to low Mg2+ concentration, due to a reversible conformational change that entails nucleotides (nt) in the neck helix (h28) and 3' tail of 16S rRNA. This active-to-inactive transition involves partial unwinding of h28 and re-pairing of nt 921-923 with nt 1532-1534, which requires flipping of the 3' tail by ~180 degrees. Growing evidence suggests that immature 30S particles adopt the inactive conformation in the cell, and transition to the active state occurs at a late stage of maturation. Here, we target nucleotides that form the alternative helix (hALT) of the inactive state. Using an orthogonal ribosome system, we find that disruption of hALT decreases translation activity in the cell modestly, by ~2-fold, without compromising ribosome fidelity. Ribosomes carrying substitutions at positions 1532-1533 support growth of E. coli strain Δ7 prrn (which carries a single rRNA operon), albeit at rates 10-20% slower than wild-type ribosomes. These mutant Δ7 prrn strains accumulate free 30S particles and precursor 17S rRNA, indicative of biogenesis defects. Analysis of purified control and mutant subunits suggests that hALT stabilizes the inactive state by 1.2 kcal/mol with little-to-no impact on the active state or the transition state of conversion.
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2
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Naeem FM, Gemler BT, McNutt ZA, Bundschuh R, Fredrick K. Analysis of programmed frameshifting during translation of prfB in Flavobacterium johnsoniae. RNA 2024; 30:136-148. [PMID: 37949662 PMCID: PMC10798248 DOI: 10.1261/rna.079721.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 10/27/2023] [Indexed: 11/12/2023]
Abstract
Ribosomes of Bacteroidia fail to recognize Shine-Dalgarno (SD) sequences due to sequestration of the 3' tail of the 16S rRNA on the 30S platform. Yet in these organisms, the prfB gene typically contains the programmed +1 frameshift site with its characteristic SD sequence. Here, we investigate prfB autoregulation in Flavobacterium johnsoniae, a member of the Bacteroidia. We find that the efficiency of prfB frameshifting in F. johnsoniae is low (∼7%) relative to that in Escherichia coli (∼50%). Mutation or truncation of bS21 in F. johnsoniae increases frameshifting substantially, suggesting that anti-SD (ASD) sequestration is responsible for the reduced efficiency. The frameshift site of certain Flavobacteriales, such as Winogradskyella psychrotolerans, has no SD. In F. johnsoniae, this W. psychrotolerans sequence supports frameshifting as well as the native sequence, and mutation of bS21 causes no enhancement. These data suggest that prfB frameshifting normally occurs without SD-ASD pairing, at least under optimal laboratory growth conditions. Chromosomal mutations that remove the frameshift or ablate the SD confer subtle growth defects in the presence of paraquat or streptomycin, respectively, indicating that both the autoregulatory mechanism and the SD element contribute to F. johnsoniae cell fitness. Analysis of prfB frameshift sites across 2686 representative bacteria shows loss of the SD sequence in many clades, with no obvious relationship to genome-wide SD usage. These data reveal unexpected variation in the mechanism of frameshifting and identify another group of organisms, the Verrucomicrobiales, that globally lack SD sequences.
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Affiliation(s)
- Fawwaz M Naeem
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Bryan T Gemler
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA
| | - Zakkary A McNutt
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
| | - Kurt Fredrick
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
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3
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Warner BR, Bundschuh R, Fredrick K. Roles of the leader-trailer helix and antitermination complex in biogenesis of the 30S ribosomal subunit. Nucleic Acids Res 2023; 51:5242-5254. [PMID: 37102690 PMCID: PMC10250234 DOI: 10.1093/nar/gkad316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 04/07/2023] [Accepted: 04/13/2023] [Indexed: 04/28/2023] Open
Abstract
Ribosome biogenesis occurs co-transcriptionally and entails rRNA folding, ribosomal protein binding, rRNA processing, and rRNA modification. In most bacteria, the 16S, 23S and 5S rRNAs are co-transcribed, often with one or more tRNAs. Transcription involves a modified RNA polymerase, called the antitermination complex, which forms in response to cis-acting elements (boxB, boxA and boxC) in the nascent pre-rRNA. Sequences flanking the rRNAs are complementary and form long helices known as leader-trailer helices. Here, we employed an orthogonal translation system to interrogate the functional roles of these RNA elements in 30S subunit biogenesis in Escherichia coli. Mutations that disrupt the leader-trailer helix caused complete loss of translation activity, indicating that this helix is absolutely essential for active subunit formation in the cell. Mutations of boxA also reduced translation activity, but by only 2- to 3-fold, suggesting a smaller role for the antitermination complex. Similarly modest drops in activity were seen upon deletion of either or both of two leader helices, termed here hA and hB. Interestingly, subunits formed in the absence of these leader features exhibited defects in translational fidelity. These data suggest that the antitermination complex and precursor RNA elements help to ensure quality control during ribosome biogenesis.
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Affiliation(s)
- Benjamin R Warner
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA
- Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus,OH 43210, USA
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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4
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McNutt ZA, Roy B, Gemler BT, Shatoff EA, Moon KM, Foster LJ, Bundschuh R, Fredrick K. Ribosomes lacking bS21 gain function to regulate protein synthesis in Flavobacterium johnsoniae. Nucleic Acids Res 2023; 51:1927-1942. [PMID: 36727479 PMCID: PMC9976891 DOI: 10.1093/nar/gkad047] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 02/03/2023] Open
Abstract
Ribosomes of Bacteroidia (formerly Bacteroidetes) fail to recognize Shine-Dalgarno (SD) sequences even though they harbor the anti-SD (ASD) of 16S rRNA. Inhibition of SD-ASD pairing is due to sequestration of the 3' tail of 16S rRNA in a pocket formed by bS21, bS18, and bS6 on the 30S platform. Interestingly, in many Flavobacteriales, the gene encoding bS21, rpsU, contains an extended SD sequence. In this work, we present genetic and biochemical evidence that bS21 synthesis in Flavobacterium johnsoniae is autoregulated via a subpopulation of ribosomes that specifically lack bS21. Mutation or depletion of bS21 in the cell increases translation of reporters with strong SD sequences, such as rpsU'-gfp, but has no effect on other reporters. Purified ribosomes lacking bS21 (or its C-terminal region) exhibit higher rates of initiation on rpsU mRNA and lower rates of initiation on other (SD-less) mRNAs than control ribosomes. The mechanism of autoregulation depends on extensive pairing between mRNA and 16S rRNA, and exceptionally strong SD sequences, with predicted pairing free energies of < -13 kcal/mol, are characteristic of rpsU across the Bacteroidota. This work uncovers a clear example of specialized ribosomes in bacteria.
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Affiliation(s)
- Zakkary A McNutt
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Bappaditya Roy
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Bryan T Gemler
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Elan A Shatoff
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Kyung-Mee Moon
- Department of Biochemistry and Molecular Biology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V3T1Z4, Canada
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V3T1Z4, Canada
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
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5
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Zayed AA, Wainaina JM, Dominguez-Huerta G, Pelletier E, Guo J, Mohssen M, Tian F, Pratama AA, Bolduc B, Zablocki O, Cronin D, Solden L, Delage E, Alberti A, Aury JM, Carradec Q, da Silva C, Labadie K, Poulain J, Ruscheweyh HJ, Salazar G, Shatoff E, Coordinators TO, Bundschuh R, Fredrick K, Kubatko LS, Chaffron S, Culley AI, Sunagawa S, Kuhn JH, Wincker P, Sullivan MB. Cryptic and abundant marine viruses at the evolutionary origins of Earth's RNA virome. Science 2022; 376:156-162. [PMID: 35389782 PMCID: PMC10990476 DOI: 10.1126/science.abm5847] [Citation(s) in RCA: 87] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Whereas DNA viruses are known to be abundant, diverse, and commonly key ecosystem players, RNA viruses are insufficiently studied outside disease settings. In this study, we analyzed ≈28 terabases of Global Ocean RNA sequences to expand Earth's RNA virus catalogs and their taxonomy, investigate their evolutionary origins, and assess their marine biogeography from pole to pole. Using new approaches to optimize discovery and classification, we identified RNA viruses that necessitate substantive revisions of taxonomy (doubling phyla and adding >50% new classes) and evolutionary understanding. "Species"-rank abundance determination revealed that viruses of the new phyla "Taraviricota," a missing link in early RNA virus evolution, and "Arctiviricota" are widespread and dominant in the oceans. These efforts provide foundational knowledge critical to integrating RNA viruses into ecological and epidemiological models.
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Affiliation(s)
- Ahmed A. Zayed
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - James M. Wainaina
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - Guillermo Dominguez-Huerta
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - Eric Pelletier
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Jiarong Guo
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - Mohamed Mohssen
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
- The Interdisciplinary Biophysics Graduate Program, Ohio State University, Columbus, OH 43210, USA
| | - Funing Tian
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - Akbar Adjie Pratama
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
| | - Benjamin Bolduc
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - Olivier Zablocki
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - Dylan Cronin
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
| | - Lindsey Solden
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
| | - Erwan Delage
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
- Nantes Université, CNRS UMR 6004, LS2N, F-44000 Nantes, France
| | - Adriana Alberti
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Jean-Marc Aury
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Quentin Carradec
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Corinne da Silva
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Karine Labadie
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Julie Poulain
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Hans-Joachim Ruscheweyh
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zurich, Zurich, Switzerland
| | - Guillem Salazar
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zurich, Zurich, Switzerland
| | - Elan Shatoff
- Department of Physics, Ohio State University, Columbus, OH 43210, USA
| | | | - Ralf Bundschuh
- The Interdisciplinary Biophysics Graduate Program, Ohio State University, Columbus, OH 43210, USA
- Department of Physics, Ohio State University, Columbus, OH 43210, USA
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA
- Division of Hematology, Department of Internal Medicine, Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
| | - Laura S. Kubatko
- Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH 43210, USA
- Department of Statistics, Ohio State University, Columbus, OH 43210, USA
| | - Samuel Chaffron
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
- Nantes Université, CNRS UMR 6004, LS2N, F-44000 Nantes, France
| | - Alexander I. Culley
- Département de Biochimie, Microbiologie et Bio-informatique, Université Laval, Québec, Québec G1V 0A6, Canada
| | - Shinichi Sunagawa
- Department of Biology, Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zurich, Zurich, Switzerland
| | - Jens H. Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Patrick Wincker
- Génomique Métabolique, Genoscope, Institut François-Jacob, CEA, CNRS, Univ Evry, Université Paris-Saclay, 91000 Evry, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans GOSEE, 75016 Paris, France
| | - Matthew B. Sullivan
- Department of Microbiology, Ohio State University, Columbus, OH 43210, USA
- EMERGE Biology Integration Institute, Ohio State University, Columbus, OH 43210, USA
- Center of Microbiome Science, Ohio State University, Columbus, OH 43210, USA
- The Interdisciplinary Biophysics Graduate Program, Ohio State University, Columbus, OH 43210, USA
- Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH 43210, USA
- Department of Civil, Environmental, and Geodetic Engineering, Ohio State University, Columbus, OH 43210, USA
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6
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McNutt ZA, Gandhi MD, Shatoff EA, Roy B, Devaraj A, Bundschuh R, Fredrick K. Comparative Analysis of anti-Shine- Dalgarno Function in Flavobacterium johnsoniae and Escherichia coli. Front Mol Biosci 2021; 8:787388. [PMID: 34966783 PMCID: PMC8710568 DOI: 10.3389/fmolb.2021.787388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/08/2021] [Indexed: 12/03/2022] Open
Abstract
The anti-Shine-Dalgarno (ASD) sequence of 16S rRNA is highly conserved across Bacteria, and yet usage of Shine-Dalgarno (SD) sequences in mRNA varies dramatically, depending on the lineage. Here, we compared the effects of ASD mutagenesis in Escherichia coli, a Gammaproteobacteria which commonly employs SD sequences, and Flavobacterium johnsoniae, a Bacteroidia which rarely does. In E. coli, 30S subunits carrying any single substitution at positions 1,535–1,539 confer dominant negative phenotypes, whereas subunits with mutations at positions 1,540–1,542 are sufficient to support cell growth. These data suggest that CCUCC (1,535–1,539) represents the functional core of the element in E. coli. In F. johnsoniae, deletion of three ribosomal RNA (rrn) operons slowed growth substantially, a phenotype largely rescued by a plasmid-borne copy of the rrn operon. Using this complementation system, we found that subunits with single mutations at positions 1,535–1,537 are as active as control subunits, in sharp contrast to the E. coli results. Moreover, subunits with quadruple substitution or complete replacement of the ASD retain substantial, albeit reduced, activity. Sedimentation analysis revealed that these mutant subunits are overrepresented in the subunit fractions and underrepresented in polysome fractions, suggesting some defect in 30S biogenesis and/or translation initiation. Nonetheless, our collective data indicate that the ASD plays a much smaller role in F. johnsoniae than in E. coli, consistent with SD usage in the two organisms.
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Affiliation(s)
- Zakkary A McNutt
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, United States.,Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Mai D Gandhi
- Department of Microbiology, The Ohio State University, Columbus, OH, United States
| | - Elan A Shatoff
- Center for RNA Biology, The Ohio State University, Columbus, OH, United States.,Department of Physics, The Ohio State University, Columbus, OH, United States
| | - Bappaditya Roy
- Center for RNA Biology, The Ohio State University, Columbus, OH, United States.,Department of Microbiology, The Ohio State University, Columbus, OH, United States
| | - Aishwarya Devaraj
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, United States.,Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH, United States.,Department of Physics, The Ohio State University, Columbus, OH, United States.,Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, United, States.,Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, United States
| | - Kurt Fredrick
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, United States.,Center for RNA Biology, The Ohio State University, Columbus, OH, United States.,Department of Microbiology, The Ohio State University, Columbus, OH, United States
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7
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Shatoff EA, Gemler BT, Bundschuh R, Fredrick K. Maturation of 23S rRNA includes removal of helix H1 in many bacteria. RNA Biol 2021; 18:856-865. [PMID: 34812116 PMCID: PMC8782170 DOI: 10.1080/15476286.2021.2000793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In most bacteria, the three ribosomal RNAs (rRNAs) are encoded together in each of several near-identical operons. As soon as the nascent precursor rRNA emerges from RNA polymerase, ribosome assembly begins. This process entails ribosomal protein binding, rRNA folding, rRNA modification, and rRNA processing. In the model organisms Escherichia coli and Bacillus subtilis, rRNA processing results in similar mature rRNAs, despite substantial differences in the cohort of RNAses involved. A recent study of Flavobacterium johnsoniae, a member of the phylum Bacteroidota (formerly Bacteroidetes), revealed that helix H1 of 23S rRNA is absent from ribosomes, apparently a consequence of rRNA maturation. In this work, we mined RNA-seq data from 19 individual organisms and ocean metatranscriptomic samples to compare rRNA processing across diverse bacterial lineages. We found that mature ribosomes from multiple clades lack H1, and typically these ribosomes also lack an encoded H98. For all groups analysed, H1 is predicted to form in precursor rRNA as part of a longer leader-trailer helix. Hence, we infer that evolutionary loss of H98 sets the stage for H1 removal during 50S subunit maturation.
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Affiliation(s)
- Elan A Shatoff
- Department of Physics, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Bryan T Gemler
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA
| | - Ralf Bundschuh
- Department of Physics, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH, USA.,Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH, USA.,Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH, USA
| | - Kurt Fredrick
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Department of Microbiology, The Ohio State University, Columbus, OH, USA
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8
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del Peso Santos T, Alvarez L, Sit B, Irazoki O, Blake J, Warner BR, Warr AR, Bala A, Benes V, Waldor MK, Fredrick K, Cava F. BipA exerts temperature-dependent translational control of biofilm-associated colony morphology in Vibrio cholerae. eLife 2021; 10:e60607. [PMID: 33588990 PMCID: PMC7886329 DOI: 10.7554/elife.60607] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 02/03/2021] [Indexed: 12/18/2022] Open
Abstract
Adaptation to shifting temperatures is crucial for the survival of the bacterial pathogen Vibrio cholerae. Here, we show that colony rugosity, a biofilm-associated phenotype, is regulated by temperature in V. cholerae strains that naturally lack the master biofilm transcriptional regulator HapR. Using transposon-insertion mutagenesis, we found the V. cholerae ortholog of BipA, a conserved ribosome-associated GTPase, is critical for this temperature-dependent phenomenon. Proteomic analyses revealed that loss of BipA alters the synthesis of >300 proteins in V. cholerae at 22°C, increasing the production of biofilm-related proteins including the key transcriptional activators VpsR and VpsT, as well as proteins important for diverse cellular processes. At low temperatures, BipA protein levels increase and are required for optimal ribosome assembly in V. cholerae, suggesting that control of BipA abundance is a mechanism by which bacteria can remodel their proteomes. Our study reveals a remarkable new facet of V. cholerae's complex biofilm regulatory network.
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Affiliation(s)
- Teresa del Peso Santos
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Laura Alvarez
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Brandon Sit
- Howard Hughes Medical Institute, Brigham and Women's Hospital Division of Infectious Diseases and Harvard Medical School Department of Microbiology and ImmunobiologyBoston, MAUnited States
| | - Oihane Irazoki
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Jonathon Blake
- Genomics Core Facility, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Benjamin R Warner
- Department of Microbiology, The Ohio State UniversityColumbus, OHUnited States
- Center for RNA Biology, The Ohio State UniversityColumbus, OHUnited States
| | - Alyson R Warr
- Howard Hughes Medical Institute, Brigham and Women's Hospital Division of Infectious Diseases and Harvard Medical School Department of Microbiology and ImmunobiologyBoston, MAUnited States
| | - Anju Bala
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
| | - Vladimir Benes
- Genomics Core Facility, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Matthew K Waldor
- Howard Hughes Medical Institute, Brigham and Women's Hospital Division of Infectious Diseases and Harvard Medical School Department of Microbiology and ImmunobiologyBoston, MAUnited States
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State UniversityColumbus, OHUnited States
- Center for RNA Biology, The Ohio State UniversityColumbus, OHUnited States
| | - Felipe Cava
- The laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå UniversityUmeåSweden
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9
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Jha V, Roy B, Jahagirdar D, McNutt ZA, Shatoff EA, Boleratz BL, Watkins DE, Bundschuh R, Basu K, Ortega J, Fredrick K. Structural basis of sequestration of the anti-Shine-Dalgarno sequence in the Bacteroidetes ribosome. Nucleic Acids Res 2021; 49:547-567. [PMID: 33330920 PMCID: PMC7797042 DOI: 10.1093/nar/gkaa1195] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 11/18/2020] [Accepted: 11/24/2020] [Indexed: 11/25/2022] Open
Abstract
Genomic studies have indicated that certain bacterial lineages such as the Bacteroidetes lack Shine-Dalgarno (SD) sequences, and yet with few exceptions ribosomes of these organisms carry the canonical anti-SD (ASD) sequence. Here, we show that ribosomes purified from Flavobacterium johnsoniae, a representative of the Bacteroidetes, fail to recognize the SD sequence of mRNA in vitro. A cryo-electron microscopy structure of the complete 70S ribosome from F. johnsoniae at 2.8 Å resolution reveals that the ASD is sequestered by ribosomal proteins bS21, bS18 and bS6, explaining the basis of ASD inhibition. The structure also uncovers a novel ribosomal protein—bL38. Remarkably, in F. johnsoniae and many other Flavobacteriia, the gene encoding bS21 contains a strong SD, unlike virtually all other genes. A subset of Flavobacteriia have an alternative ASD, and in these organisms the fully complementary sequence lies upstream of the bS21 gene, indicative of natural covariation. In other Bacteroidetes classes, strong SDs are frequently found upstream of the genes for bS21 and/or bS18. We propose that these SDs are used as regulatory elements, enabling bS21 and bS18 to translationally control their own production.
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Affiliation(s)
- Vikash Jha
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Dushyant Jahagirdar
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Zakkary A McNutt
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Elan A Shatoff
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Bethany L Boleratz
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Dean E Watkins
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry & Biochemistry, Division of Hematology, The Ohio State University, Columbus, OH 43210, USA
| | - Kaustuv Basu
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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10
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Chen M, Fredrick K. RNA Polymerase's Relationship with the Ribosome: Not So Physical, Most of the Time. J Mol Biol 2020; 432:3981-3986. [PMID: 32198117 DOI: 10.1016/j.jmb.2020.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/03/2020] [Accepted: 03/11/2020] [Indexed: 01/19/2023]
Abstract
In bacteria, the rates of transcription elongation and translation elongation are coordinated, changing together in response to growth conditions. It has been proposed that this is due to physical coupling of RNA polymerase and the lead ribosome on nascent mRNA, an interaction important for preventing premature transcription termination by Rho factor. Recent studies challenge this view and provide evidence that coordination is indirect, mediated in Escherichia coli by the alarmone (p)ppGpp. Here, we discuss these new findings and how they shape our understanding of the functional relationship between RNA polymerase and the ribosome as well as the basis of transcriptional polarity.
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Affiliation(s)
- Menglin Chen
- Department of Microbiology, Ohio State Biochemistry Program, and Center for RNA Biology, The Ohio State University, 484 W. 12(th) Ave, Columbus, OH, 43210, USA
| | - Kurt Fredrick
- Department of Microbiology, Ohio State Biochemistry Program, and Center for RNA Biology, The Ohio State University, 484 W. 12(th) Ave, Columbus, OH, 43210, USA.
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11
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Ying L, Zhu H, Fosso MY, Garneau-Tsodikova S, Fredrick K. Modified Aminoglycosides Bind Nucleic Acids in High-Molecular-Weight Complexes. Antibiotics (Basel) 2020; 9:antibiotics9020093. [PMID: 32098020 PMCID: PMC7168264 DOI: 10.3390/antibiotics9020093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/05/2022] Open
Abstract
Aminoglycosides represent a large group of antibiotics well known for their ability to target the bacterial ribosome. In studying 6”-substituted variants of the aminoglycoside tobramycin, we serendipitously found that compounds with C12 or C14 linear alkyl substituents potently inhibit reverse transcription in vitro. Initial observations suggested specific inhibition of reverse transcriptase. However, further analysis showed that these and related compounds bind nucleic acids with high affinity, forming high-molecular weight complexes. Stable complex formation is observed with DNA or RNA in single- or double-stranded form. Given the amphiphilic nature of these aminoglycoside derivatives, they likely form micelles and/or vesicles with surface-bound nucleic acids. Hence, these compounds may be useful tools to localize nucleic acids to surfaces or deliver nucleic acids to cells or organelles.
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Affiliation(s)
- Lanqing Ying
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH 43210-1292, USA; (L.Y.); (H.Z.)
| | - Hongkun Zhu
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH 43210-1292, USA; (L.Y.); (H.Z.)
| | - Marina Y. Fosso
- Department of Pharmaceutical Sciences in the College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA; (M.Y.F.); (S.G.-T.)
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences in the College of Pharmacy, University of Kentucky, Lexington, KY 40536-0596, USA; (M.Y.F.); (S.G.-T.)
| | - Kurt Fredrick
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH 43210-1292, USA; (L.Y.); (H.Z.)
- Correspondence: ; Tel.: +1-614-292-6679
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12
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Baez WD, Roy B, McNutt ZA, Shatoff EA, Chen S, Bundschuh R, Fredrick K. Global analysis of protein synthesis in Flavobacterium johnsoniae reveals the use of Kozak-like sequences in diverse bacteria. Nucleic Acids Res 2019; 47:10477-10488. [PMID: 31602466 PMCID: PMC6847099 DOI: 10.1093/nar/gkz855] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/16/2019] [Accepted: 09/30/2019] [Indexed: 12/31/2022] Open
Abstract
In all cells, initiation of translation is tuned by intrinsic features of the mRNA. Here, we analyze translation in Flavobacterium johnsoniae, a representative of the Bacteroidetes. Members of this phylum naturally lack Shine-Dalgarno (SD) sequences in their mRNA, and yet their ribosomes retain the conserved anti-SD sequence. Translation initiation is tuned by mRNA secondary structure and by the identities of several key nucleotides upstream of the start codon. Positive determinants include adenine at position -3, reminiscent of the Kozak sequence of Eukarya. Comparative analysis of Escherichia coli reveals use of the same Kozak-like sequence to enhance initiation, suggesting an ancient and widespread mechanism. Elimination of contacts between A-3 and the conserved β-hairpin of ribosomal protein uS7 fails to diminish the contribution of A-3 to initiation, suggesting an indirect mode of recognition. Also, we find that, in the Bacteroidetes, the trinucleotide AUG is underrepresented in the vicinity of the start codon, which presumably helps compensate for the absence of SD sequences in these organisms.
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Affiliation(s)
- William D Baez
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Bappaditya Roy
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Zakkary A McNutt
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Elan A Shatoff
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Shicheng Chen
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Ralf Bundschuh
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Chemistry and Biochemistry, Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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13
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Hoffer ED, Maehigashi T, Fredrick K, Dunham CM. Ribosomal ambiguity (ram) mutations promote the open (off) to closed (on) transition and thereby increase miscoding. Nucleic Acids Res 2019; 47:1557-1563. [PMID: 30476222 PMCID: PMC6379664 DOI: 10.1093/nar/gky1178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 10/31/2018] [Accepted: 11/05/2018] [Indexed: 01/18/2023] Open
Abstract
Decoding is thought to be governed by a conformational transition in the ribosome—open (off) to closed (on)—that occurs upon codon–anticodon pairing in the A site. Ribosomal ambiguity (ram) mutations increase miscoding and map to disparate regions, consistent with a role for ribosome dynamics in decoding, yet precisely how these mutations act has been unclear. Here, we solved crystal structures of 70S ribosomes harboring 16S ram mutations G299A and G347U in the absence A-site tRNA (A-tRNA) and in the presence of a near-cognate anticodon stem-loop (ASL). In the absence of an A-tRNA, each of the mutant ribosomes exhibits a partially closed (on) state. In the 70S-G347U structure, the 30S shoulder is rotated inward and intersubunit bridge B8 is disrupted. In the 70S-G299A structure, the 30S shoulder is rotated inward and decoding nucleotide G530 flips into the anti conformation. Both of these mutant ribosomes adopt the fully closed (on) conformation in the presence of near-cognate A-tRNA, just as they do with cognate A-tRNA. Thus, these ram mutations act by promoting the open (off) to closed (on) transition, albeit in somewhat distinct ways. This work reveals the functional importance of 30S shoulder rotation for productive aminoacylated-tRNA incorporation.
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Affiliation(s)
- Eric D Hoffer
- Department of Biochemistry and Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Tatsuya Maehigashi
- Department of Biochemistry and Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Kurt Fredrick
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Correspondence may also be addressed to Kurt Fredrick. Tel: +1 614 292 6679; Fax: +1 614 292 8120;
| | - Christine M Dunham
- Department of Biochemistry and Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, GA 30322, USA
- To whom correspondence should be addressed. Tel: +1 404 712 1756; Fax: +1 404 727 2738; E-mail:
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14
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Hoffer ED, Maehigashi T, Fredrick K, Dunham CM. Ribosomal ambiguity (
ram
) mutations promote 30S domain closure and thereby increase miscoding. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.628.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Ying L, Zhu H, Shoji S, Fredrick K. Roles of specific aminoglycoside-ribosome interactions in the inhibition of translation. RNA 2019; 25:247-254. [PMID: 30413565 PMCID: PMC6348987 DOI: 10.1261/rna.068460.118] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/06/2018] [Indexed: 05/18/2023]
Abstract
Aminoglycosides containing a 2-deoxystreptamine core (AGs) represent a large family of antibiotics that target the ribosome. These compounds promote miscoding, inhibit translocation, and inhibit ribosome recycling. AG binding to helix h44 of the small subunit induces rearrangement of A-site nucleotides A1492 and A1493, which promotes a key open-to-closed conformational change of the subunit and thereby increases miscoding. Mechanisms by which AGs inhibit translocation and recycling remain less clear. Structural studies have revealed a secondary AG binding site in H69 of the large subunit, and it has been proposed that interaction at this site is crucial for inhibition of translocation and recycling. Here, we analyze ribosomes with mutations targeting either or both AG binding sites. Assaying translocation, we find that ablation of the h44 site increases the IC50 values for AGs dramatically, while removal of the H69 site increases these values modestly. This suggests that the AG-h44 interaction is primarily responsible for inhibition, with H69 playing a minor role. Assaying recycling, we find that mutation of h44 has no effect on AG inhibition, consistent with a primary role for AG-H69 interaction. Collectively, these findings help clarify the roles of the two AG binding sites in mechanisms of inhibition by these compounds.
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Affiliation(s)
- Lanqing Ying
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Hongkun Zhu
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Shinichiro Shoji
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Kurt Fredrick
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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16
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Zhao D, Baez WD, Fredrick K, Bundschuh R. RiboProP: a probabilistic ribosome positioning algorithm for ribosome profiling. Bioinformatics 2018; 35:1486-1493. [DOI: 10.1093/bioinformatics/bty854] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 09/03/2018] [Accepted: 10/09/2018] [Indexed: 11/14/2022] Open
Abstract
Abstract
Motivation
Ribosome profiling has been widely used to study translation in a genome-wide fashion. It requires deep sequencing of ribosome protected mRNA fragments followed by mapping of fragments to the reference genome. For applications such as identification of ribosome pausing sites, it is not enough to map a fragment to a given gene, but the exact position of the ribosome represented by the fragment must be identified for each mRNA fragment. The assignment of the correct ribosome position is complicated by the broad length distribution of the ribosome protected fragments caused by the known sequence bias of micrococcal nuclease (MNase), the most widely used nuclease for digesting mRNAs in bacteria. Available mapping algorithms suffer from either MNase bias or low accuracy in characterizing the ribosome pausing kinetics.
Results
In this paper, we introduce a new computational method for mapping the ribosome protected fragments to ribosome locations. We first develop a mathematical model of the interplay between MNase digestion and ribosome protection of the mRNAs. We then use the model to reconstruct the ribosome occupancy profile on a per gene level. We demonstrate that our method has the capability of mitigating the sequence bias introduced by MNase and accurately locating ribosome pausing sites at codon resolution. We believe that our method can be broadly applied to ribosome profiling studies on bacteria where codon resolution is necessary.
Availability and implementation
Source code implementing our approach can be downloaded under GPL3 license at http://bioserv.mps.ohio-state.edu/RiboProP.
Supplementary information
Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Dengke Zhao
- Interdisciplinary Biophysics Graduate Program, Division of Hematology, The Ohio State University, Columbus, OH, USA
| | - William D Baez
- Department of Physics, Division of Hematology, The Ohio State University, Columbus, OH, USA
| | - Kurt Fredrick
- Department of Microbiology, Division of Hematology, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, Division of Hematology, The Ohio State University, Columbus, OH, USA
| | - Ralf Bundschuh
- Interdisciplinary Biophysics Graduate Program, Division of Hematology, The Ohio State University, Columbus, OH, USA
- Department of Physics, Division of Hematology, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, Division of Hematology, The Ohio State University, Columbus, OH, USA
- Department of Chemistry & Biochemistry, Division of Hematology, The Ohio State University, Columbus, OH, USA
- Department of Internal Medicine, Division of Hematology, The Ohio State University, Columbus, OH, USA
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17
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Vo MN, Terrey M, Lee JW, Roy B, Moresco JJ, Sun L, Fu H, Liu Q, Weber TG, Yates JR, Fredrick K, Schimmel P, Ackerman SL. Publisher Correction: ANKRD16 prevents neuron loss caused by an editing-defective tRNA synthetase. Nature 2018; 560:E35. [PMID: 29925958 DOI: 10.1038/s41586-018-0271-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the Fig. 3b western blot of this Article, 'Myc-AlaRS' in row one should have been 'Myc-AAD Aars', 'AlaRS' in row two should have been 'Aars' and 'ANKRD16' in row four should have been 'Ankrd16'. In Fig. 4f, 'ANKRD16' and 'ANKRD16(3xR)' should have been 'Ankrd16' and 'Ankrd163xR; and in Fig. 3c the position of the molecular mass markers had shifted. These figures have been corrected online, and see Supplementary Information to the accompanying Amendment for the original figure.
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Affiliation(s)
- My-Nuong Vo
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Markus Terrey
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA.,Section of Neurobiology, University of California San Diego, La Jolla, CA, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.,The Jackson Laboratory, Bar Harbor, ME, USA
| | - Jeong Woong Lee
- The Jackson Laboratory, Bar Harbor, ME, USA.,Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - James J Moresco
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA, USA.,Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Litao Sun
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Hongjun Fu
- The Jackson Laboratory, Bar Harbor, ME, USA.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA.,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Qi Liu
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA.,Sharklet Technologies, Aurora, CO, USA
| | | | - John R Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA, USA
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Paul Schimmel
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA. .,The Scripps Research Institute, Jupiter, FL, USA.
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,Section of Neurobiology, University of California San Diego, La Jolla, CA, USA. .,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA. .,The Jackson Laboratory, Bar Harbor, ME, USA.
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18
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Vo MN, Terrey M, Lee JW, Roy B, Moresco JJ, Sun L, Fu H, Liu Q, Weber TG, Yates JR, Fredrick K, Schimmel P, Ackerman SL. ANKRD16 prevents neuron loss caused by an editing-defective tRNA synthetase. Nature 2018; 557:510-515. [PMID: 29769718 PMCID: PMC5973781 DOI: 10.1038/s41586-018-0137-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 04/09/2018] [Indexed: 11/29/2022]
Abstract
Editing domains of aminoacyl tRNA synthetases correct tRNA charging errors to maintain translational fidelity. A mutation in the editing domain of alanyl tRNA synthetase (AlaRS) in Aarssti mutant mice resulted in an increased production of serine-mischarged tRNAAla and degeneration of cerebellar Purkinje cells. By positional cloning, we identified Ankrd16, which acts epistatically with the Aarssti mutation to attenuate neurodegeneration. ANKRD16, a vertebrate-specific, ankyrin repeat-containing protein, binds directly to the catalytic domain of AlaRS. Serine misactivated by AlaRS is captured by lysine side chains of ANKRD16, preventing the charging of serine adenylates to tRNAAla and precluding serine misincorporation in nascent peptides. Deletion of Ankrd16 in the Aarssti/sti brain causes widespread protein aggregation and neuron loss. These results identify a novel amino acid-accepting co-regulator of tRNA synthetase editing as a new layer of the machinery essential for preventing severe pathologies that arise from defects in editing.
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Affiliation(s)
- My-Nuong Vo
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Markus Terrey
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA.,Section of Neurobiology, University of California San Diego, La Jolla, CA, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA.,The Jackson Laboratory, Bar Harbor, ME, USA
| | - Jeong Woong Lee
- The Jackson Laboratory, Bar Harbor, ME, USA.,Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - James J Moresco
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA, USA.,Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Litao Sun
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA
| | - Hongjun Fu
- The Jackson Laboratory, Bar Harbor, ME, USA.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA.,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Qi Liu
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH, USA.,Sharklet Technologies, Aurora, CO, USA
| | | | - John R Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA, USA
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Paul Schimmel
- The Skaggs Institute for Chemical Biology, Department of Molecular Medicine, Scripps Research Institute, La Jolla, CA, USA. .,The Scripps Research Institute, Jupiter, FL, USA.
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA. .,Section of Neurobiology, University of California San Diego, La Jolla, CA, USA. .,Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME, USA. .,The Jackson Laboratory, Bar Harbor, ME, USA.
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19
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Gibbs MR, Fredrick K. Roles of elusive translational GTPases come to light and inform on the process of ribosome biogenesis in bacteria. Mol Microbiol 2017; 107:445-454. [PMID: 29235176 DOI: 10.1111/mmi.13895] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 12/25/2022]
Abstract
Protein synthesis relies on several translational GTPases (trGTPases), related proteins that couple the hydrolysis of GTP to specific molecular events on the ribosome. Most bacterial trGTPases, including IF2, EF-Tu, EF-G and RF3, play well-known roles in translation. The cellular functions of LepA (also termed EF4) and BipA (also termed TypA), conversely, have remained enigmatic. Recent studies provide compelling in vivo evidence that LepA and BipA function in biogenesis of the 30S and 50S subunit respectively. These findings have important implications for ribosome biogenesis in bacteria. Because the GTPase activity of each of these proteins depends on interactions with both ribosomal subunits, some portion of 30S and 50S assembly must occur in the context of the 70S ribosome. In this review, we introduce the trGTPases of bacteria, describe the new functional data on LepA and BipA, and discuss the how these findings shape our current view of ribosome biogenesis in bacteria.
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Affiliation(s)
- Michelle R Gibbs
- Department of Microbiology and Center for RNA Biology, The Ohio State University, 484 W. 12th Ave, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Department of Microbiology and Center for RNA Biology, The Ohio State University, 484 W. 12th Ave, Columbus, OH 43210, USA
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20
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Abstract
Translation begins at AUG, GUG, or UUG codons in bacteria. Start codon recognition occurs in the P site, which may help explain this first-position degeneracy. However, the molecular basis of start codon specificity remains unclear. In this study, we measured the codon dependence of 30S•mRNA•tRNAfMet and 30S•mRNA•tRNAMet complex formation. We found that complex stability varies over a large range with initiator tRNAfMet, following the same trend as reported previously for initiation rate in vivo (AUG > GUG, UUG > CUG, AUC, AUA > ACG). With elongator tRNAMet, the codon dependence of binding differs qualitatively, with virtually no discrimination between GUG and CUG. A unique feature of initiator tRNAfMet is a series of three G-C basepairs in the anticodon stem, which are known to be important for efficient initiation in vivo. A mutation targeting the central of these G-C basepairs causes the mRNA binding specificity pattern to change in a way reminiscent of elongator tRNAMet. Unexpectedly, for certain complexes containing fMet-tRNAfMet, we observed mispositioning of mRNA, such that codon 2 is no longer programmed in the A site. This mRNA mispositioning is exacerbated by the anticodon stem mutation and suppressed by IF2. These findings suggest that both IF2 and the unique anticodon stem of fMet-tRNAfMet help constrain mRNA positioning to set the correct reading frame during initiation.
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Affiliation(s)
- Bappaditya Roy
- a Department of Microbiology and Center for RNA Biology , Ohio State University , Columbus , Ohio , USA
| | - Qi Liu
- a Department of Microbiology and Center for RNA Biology , Ohio State University , Columbus , Ohio , USA
| | - Shinichiro Shoji
- a Department of Microbiology and Center for RNA Biology , Ohio State University , Columbus , Ohio , USA
| | - Kurt Fredrick
- a Department of Microbiology and Center for RNA Biology , Ohio State University , Columbus , Ohio , USA
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21
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Dai X, Zhu M, Warren M, Balakrishnan R, Patsalo V, Okano H, Williamson JR, Fredrick K, Wang YP, Hwa T. Reduction of translating ribosomes enables Escherichia coli to maintain elongation rates during slow growth. Nat Microbiol 2016; 2:16231. [PMID: 27941827 PMCID: PMC5346290 DOI: 10.1038/nmicrobiol.2016.231] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 10/17/2016] [Indexed: 01/13/2023]
Abstract
Bacteria growing under different conditions experience a broad range of demand on the rate of protein synthesis, which profoundly affects cellular resource allocation. During fast growth, protein synthesis has long been known to be modulated by adjusting the ribosome content, with the vast majority of ribosomes engaged at a near-maximal rate of elongation. Here, we systematically characterize protein synthesis by Escherichia coli, focusing on slow-growth conditions. We establish that the translational elongation rate decreases as growth slows, exhibiting a Michaelis-Menten dependence on the abundance of the cellular translational apparatus. However, an appreciable elongation rate is maintained even towards zero growth, including the stationary phase. This maintenance, critical for timely protein synthesis in harsh environments, is accompanied by a drastic reduction in the fraction of active ribosomes. Interestingly, well-known antibiotics such as chloramphenicol also cause a substantial reduction in the pool of active ribosomes, instead of slowing down translational elongation as commonly thought.
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Affiliation(s)
- Xiongfeng Dai
- Department of Physics, University of California at San Diego, La Jolla CA 92093-0374
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Manlu Zhu
- Department of Physics, University of California at San Diego, La Jolla CA 92093-0374
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Mya Warren
- Department of Physics, University of California at San Diego, La Jolla CA 92093-0374
| | - Rohan Balakrishnan
- Department of Physics, University of California at San Diego, La Jolla CA 92093-0374
- Department of Microbiology and Ohio State Biochemistry Program, the Ohio State University, Columbus OH 43210
| | - Vadim Patsalo
- Department of Integrative Structural and Computational Biology, Department of Chemistry, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Hiroyuki Okano
- Department of Physics, University of California at San Diego, La Jolla CA 92093-0374
| | - James R. Williamson
- Department of Integrative Structural and Computational Biology, Department of Chemistry, and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Kurt Fredrick
- Department of Microbiology and Ohio State Biochemistry Program, the Ohio State University, Columbus OH 43210
| | - Yi-Ping Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Terence Hwa
- Department of Physics, University of California at San Diego, La Jolla CA 92093-0374
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22
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Ying L, Fredrick K. Epistasis analysis of 16S rRNA ram mutations helps define the conformational dynamics of the ribosome that influence decoding. RNA 2016; 22:499-505. [PMID: 26873598 PMCID: PMC4793206 DOI: 10.1261/rna.054486.115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/14/2016] [Indexed: 06/05/2023]
Abstract
The ribosome actively participates in decoding, with a tRNA-dependent rearrangement of the 30S A site playing a key role. Ribosomal ambiguity (ram) mutations have mapped not only to the A site but also to the h12/S4/S5 region and intersubunit bridge B8, implicating other conformational changes such as 30S shoulder rotation and B8 disruption in the mechanism of decoding. Recent crystallographic data have revealed that mutation G299A in helix h12 allosterically promotes B8 disruption, raising the question of whether G299A and/or other ram mutations act mainly via B8. Here, we compared the effects of each of several ram mutations in the absence and presence of mutation h8Δ2, which effectively takes out bridge B8. The data obtained suggest that a subset of mutations including G299A act in part via B8 but predominantly through another mechanism. We also found that G299A in h12 and G347U in h14 each stabilize tRNA in the A site. Collectively, these data support a model in which rearrangement of the 30S A site, inward shoulder rotation, and bridge B8 disruption are loosely coupled events, all of which promote progression along the productive pathway toward peptide bond formation.
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Affiliation(s)
- Lanqing Ying
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Kurt Fredrick
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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23
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Abstract
The ribosome is a large two-subunit ribonucleoprotein machine that translates the genetic code in all cells, synthesizing proteins according to the sequence of the mRNA template. During translation, the primary substrates, transfer RNAs, pass through binding sites formed between the two subunits. Multiple interactions between the ribosomal subunits, termed intersubunit bridges, keep the ribosome intact and at the same time govern dynamics that facilitate the various steps of translation such as transfer RNA-mRNA movement. Here, we review the molecular nature of these intersubunit bridges, how they change conformation during translation, and their functional roles in the process.
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Affiliation(s)
- Qi Liu
- Ohio State Biochemistry Program, Department of Microbiology, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Ohio State Biochemistry Program, Department of Microbiology, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
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24
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Fosso MY, Zhu H, Green KD, Garneau-Tsodikova S, Fredrick K. Tobramycin Variants with Enhanced Ribosome-Targeting Activity. Chembiochem 2015; 16:1565-70. [PMID: 26033429 DOI: 10.1002/cbic.201500256] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Indexed: 01/16/2023]
Abstract
With the increased evolution of aminoglycoside (AG)-resistant bacterial strains, the need to develop AGs with 1) enhanced antimicrobial activity, 2) the ability to evade resistance mechanisms, and 3) the capability of targeting the ribosome with higher efficiency is more and more pressing. The chemical derivatization of the naturally occurring tobramycin (TOB) by attachment of 37 different thioether groups at the 6''-position led to the identification of generally poorer substrates of TOB-targeting AG-modifying enzymes (AMEs). Thirteen of these displayed better antibacterial activity than the parent TOB while retaining ribosome-targeting specificity. Analysis of these compounds in vitro shed light on the mechanism by which they act and revealed three with clearly enhanced ribosome-targeting activity.
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Affiliation(s)
- Marina Y Fosso
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone, Lexington, KY 40536-0596 (USA)
| | - Hongkun Zhu
- Department of Microbiology, Center for RNA Biology, Ohio State University, 484 W. 12th Avenue, Columbus, OH 43210-1292 (USA)
| | - Keith D Green
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone, Lexington, KY 40536-0596 (USA)
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone, Lexington, KY 40536-0596 (USA).
| | - Kurt Fredrick
- Department of Microbiology, Center for RNA Biology, Ohio State University, 484 W. 12th Avenue, Columbus, OH 43210-1292 (USA).
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25
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Balakrishnan R, Oman K, Shoji S, Bundschuh R, Fredrick K. The conserved GTPase LepA contributes mainly to translation initiation in Escherichia coli. Nucleic Acids Res 2014; 42:13370-83. [PMID: 25378333 PMCID: PMC4245954 DOI: 10.1093/nar/gku1098] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
LepA is a paralog of EF-G found in all bacteria. Deletion of lepA confers no obvious growth defect in Escherichia coli, and the physiological role of LepA remains unknown. Here, we identify nine strains (ΔdksA, ΔmolR1, ΔrsgA, ΔtatB, ΔtonB, ΔtolR, ΔubiF, ΔubiG or ΔubiH) in which ΔlepA confers a synthetic growth phenotype. These strains are compromised for gene regulation, ribosome assembly, transport and/or respiration, indicating that LepA contributes to these functions in some way. We also use ribosome profiling to deduce the effects of LepA on translation. We find that loss of LepA alters the average ribosome density (ARD) for hundreds of mRNA coding regions in the cell, substantially reducing ARD in many cases. By contrast, only subtle and codon-specific changes in ribosome distribution along mRNA are seen. These data suggest that LepA contributes mainly to the initiation phase of translation. Consistent with this interpretation, the effect of LepA on ARD is related to the sequence of the Shine–Dalgarno region. Global perturbation of gene expression in the ΔlepA mutant likely explains most of its phenotypes.
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Affiliation(s)
- Rohan Balakrishnan
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Kenji Oman
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Shinichiro Shoji
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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26
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Liu T, Kaplan A, Alexander L, Yan S, Wen JD, Lancaster L, Wickersham CE, Fredrick K, Fredrik K, Noller H, Tinoco I, Bustamante CJ. Direct measurement of the mechanical work during translocation by the ribosome. eLife 2014; 3:e03406. [PMID: 25114092 PMCID: PMC4126342 DOI: 10.7554/elife.03406] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A detailed understanding of tRNA/mRNA translocation requires measurement of the forces generated by the ribosome during this movement. Such measurements have so far remained elusive and, thus, little is known about the relation between force and translocation and how this reflects on its mechanism and regulation. Here, we address these questions using optical tweezers to follow translation by individual ribosomes along single mRNA molecules, against an applied force. We find that translocation rates depend exponentially on the force, with a characteristic distance close to the one-codon step, ruling out the existence of sub-steps and showing that the ribosome likely functions as a Brownian ratchet. We show that the ribosome generates ∼13 pN of force, barely sufficient to unwind the most stable structures in mRNAs, thus providing a basis for their regulatory role. Our assay opens the way to characterizing the ribosome's full mechano-chemical cycle.
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Affiliation(s)
- Tingting Liu
- Jason L Choy Laboratory of Single Molecule Biophysics, University of California, Berkeley, Berkeley, United States Department of Physics, University of California, Berkeley, Berkeley, United States
| | - Ariel Kaplan
- Jason L Choy Laboratory of Single Molecule Biophysics, University of California, Berkeley, Berkeley, United States Department of Physics, University of California, Berkeley, Berkeley, United States Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel Lorry I Lokey Interdisciplinary Center, Technion-Israel Institute of Technology, Haifa, Israel
| | - Lisa Alexander
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Shannon Yan
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Jin-Der Wen
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Laura Lancaster
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States Center for Molecular Biology of RNA, University of California, Santa Cruz, Santa Cruz, United States
| | - Charles E Wickersham
- Jason L Choy Laboratory of Single Molecule Biophysics, University of California, Berkeley, Berkeley, United States Department of Physics, University of California, Berkeley, Berkeley, United States
| | | | - Kurt Fredrik
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States Center for Molecular Biology of RNA, University of California, Santa Cruz, Santa Cruz, United States
| | - Harry Noller
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, United States Center for Molecular Biology of RNA, University of California, Santa Cruz, Santa Cruz, United States
| | - Ignacio Tinoco
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Carlos J Bustamante
- Jason L Choy Laboratory of Single Molecule Biophysics, University of California, Berkeley, Berkeley, United States Department of Physics, University of California, Berkeley, Berkeley, United States Department of Chemistry, University of California, Berkeley, Berkeley, United States California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, United States
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27
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Affiliation(s)
- Kurt Fredrick
- Department of Microbiology, Ohio State Biochemistry Program and Center for RNA Biology, Ohio State University, Columbus, Ohio, USA
| | - Michael Ibba
- Department of Microbiology, Ohio State Biochemistry Program and Center for RNA Biology, Ohio State University, Columbus, Ohio, USA
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28
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Abstract
During decoding, the ribosome selects the correct (cognate) aminoacyl-tRNA (aa-tRNA) from a large pool of incorrect aa-tRNAs through a two-stage mechanism. In the initial selection stage, aa-tRNA is delivered to the ribosome as part of a ternary complex with elongation factor EF-Tu and GTP. Interactions between codon and anticodon lead to activation of the GTPase domain of EF-Tu and GTP hydrolysis. Then, in the proofreading stage, aa-tRNA is released from EF-Tu and either moves fully into the A/A site (a step termed "accommodation") or dissociates from the ribosome. Cognate codon-anticodon pairing not only stabilizes aa-tRNA at both stages of decoding but also stimulates GTP hydrolysis and accommodation, allowing the process to be both accurate and fast. In previous work, we isolated a number of ribosomal ambiguity (ram) mutations in 16S rRNA, implicating particular regions of the ribosome in the mechanism of decoding. Here, we analyze a representative subset of these mutations with respect to initial selection, proofreading, RF2-dependent termination, and overall miscoding in various contexts. We find that mutations that disrupt inter-subunit bridge B8 increase miscoding in a general way, causing defects in both initial selection and proofreading. Mutations in or near the A site behave differently, increasing miscoding in a codon-anticodon-dependent manner. These latter mutations may create spurious favorable interactions in the A site for certain near-cognate aa-tRNAs, providing an explanation for their context-dependent phenotypes in the cell.
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MESH Headings
- Anticodon/genetics
- Codon/genetics
- Guanosine Triphosphate/metabolism
- Kinetics
- Models, Molecular
- Mutation/genetics
- Nucleic Acid Conformation
- Peptide Termination Factors/chemistry
- Peptide Termination Factors/genetics
- Peptide Termination Factors/metabolism
- Protein Biosynthesis
- RNA, Messenger/genetics
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- RNA, Transfer, Amino Acyl/chemistry
- RNA, Transfer, Amino Acyl/genetics
- RNA, Transfer, Amino Acyl/metabolism
- Ribosomes/chemistry
- Ribosomes/genetics
- Ribosomes/metabolism
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Affiliation(s)
- Sean P. McClory
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Aishwarya Devaraj
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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29
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Kaplan A, Liu T, Wickersham C, Wen JD, Lancaster L, Fredrick K, Noller HF, Tinoco I, Bustamante C. Mechanical Force during Translocation by the Ribosome. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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30
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Abstract
In every round of translation elongation, EF-G catalyzes translocation, the movement of tRNAs (and paired codons) to their adjacent binding sites in the ribosome. Previous kinetic studies have shown that the rate of tRNA–mRNA movement is limited by a conformational change in the ribosome termed ‘unlocking’. Although structural studies offer some clues as to what unlocking might entail, the molecular basis of this conformational change remains an open question. In this study, the contribution of intersubunit bridges to the energy barrier of translocation was systematically investigated. Unlike those targeting B2a and B3, mutations that disrupt bridges B1a, B4, B7a and B8 increased the maximal rate of both forward (EF-G dependent) and reverse (spontaneous) translocation. As bridge B1a is predicted to constrain 30S head movement and B4, B7a and B8 are predicted to constrain intersubunit rotation, these data provide evidence that formation of the unlocked (transition) state involves both 30S head movement and intersubunit rotation.
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Affiliation(s)
- Qi Liu
- Ohio State Biochemistry Program, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
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31
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Qin D, Liu Q, Devaraj A, Fredrick K. Role of helix 44 of 16S rRNA in the fidelity of translation initiation. RNA 2012; 18:485-95. [PMID: 22279149 PMCID: PMC3285936 DOI: 10.1261/rna.031203.111] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/08/2011] [Indexed: 05/30/2023]
Abstract
The molecular mechanisms that govern translation initiation to ensure accuracy remain unclear. Here, we provide evidence that the subunit-joining step of initiation is controlled in part by a conformational change in the 1408 region of helix h44. First, chemical probing of 30S initiation complexes formed with either a cognate (AUG) or near-cognate (AUC) start codon shows that an IF1-dependent enhancement at A1408 is reduced in the presence of AUG. This change in reactivity is due to a conformational change rather than loss of IF1, because other portions of the IF1 footprint are unchanged and high concentrations of IF1 fail to diminish the reactivity difference seen at A1408. Second, mutations in h44 such as A1413C stimulate 50S docking and cause reduced reactivity at A1408. Third, streptomycin, which has been shown by Rodnina and coworkers to stimulate 50S docking by reversing the inhibitory effects of IF1, also causes reduced reactivity at A1408. Collectively, these data support a model in which IF1 alters the A1408 region of h44 in a way that makes 50S docking unfavorable, and canonical codon-anticodon pairing in the P site restores h44 to a docking-favorable conformation. We also find that, in the absence of factors, the cognate 30S•AUG•fMet-tRNA ternary complex is >1000-fold more stable than the near-cognate 30S•AUC•fMet-tRNA complex. Hence, the selectivity of ternary complex formation is inherently high, exceeding that of initiation in vivo by more than 10-fold.
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MESH Headings
- Codon, Initiator/genetics
- Codon, Initiator/metabolism
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Mutation
- Nucleic Acid Conformation
- Peptide Chain Initiation, Translational/drug effects
- RNA, Messenger/metabolism
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Ribosome Subunits, Small, Bacterial/metabolism
- Streptomycin/pharmacology
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Affiliation(s)
- Daoming Qin
- Department of Microbiology, Ohio State Biochemistry Program, and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Qi Liu
- Department of Microbiology, Ohio State Biochemistry Program, and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Aishwarya Devaraj
- Department of Microbiology, Ohio State Biochemistry Program, and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
| | - Kurt Fredrick
- Department of Microbiology, Ohio State Biochemistry Program, and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, USA
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32
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Devaraj A, Fredrick K. Short spacing between the Shine-Dalgarno sequence and P codon destabilizes codon-anticodon pairing in the P site to promote +1 programmed frameshifting. Mol Microbiol 2010; 78:1500-9. [PMID: 21143320 DOI: 10.1111/j.1365-2958.2010.07421.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Programmed frameshifting in the RF2 gene (prfB) involves an intragenic Shine-Dalgarno (SD) sequence. To investigate the role of SD-ASD pairing in the mechanism of frameshifting, we have analysed the effect of spacing between the SD sequence and P codon on P-site tRNA binding and RF2-dependent termination. When the spacing between an extended SD sequence and the P codon is decreased from 4 to 1 nucleotide (nt), the dissociation rate (k(off) ) for P-site tRNA increases by > 100-fold. Toeprinting analysis shows that pre-translocation complexes cannot be formed when the spacer sequence is ≤ 2 nt. Instead, the tRNA added secondarily to fill the A site and its corresponding codon move spontaneously into the P site, resulting in a complex with a 3 nt longer spacer between the SD-ASD helix and the P codon. While close proximity of the SD clearly destabilizes P-site tRNA, RF2-dependent termination and EF-Tu-dependent decoding are largely unaffected in analogous complexes. These data support a model in which formation of the SD-ASD helix in ribosomes stalled at the in-frame UGA codon of prfB generates tension on the mRNA that destabilizes codon-anticodon pairing in the P site and promotes slippage of the mRNA in the 5' direction.
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Affiliation(s)
- Aishwarya Devaraj
- Ohio State Biochemistry Program Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
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33
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McClory SP, Leisring JM, Qin D, Fredrick K. Missense suppressor mutations in 16S rRNA reveal the importance of helices h8 and h14 in aminoacyl-tRNA selection. RNA 2010; 16:1925-34. [PMID: 20699303 PMCID: PMC2941101 DOI: 10.1261/rna.2228510] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The molecular basis of the induced-fit mechanism that determines the fidelity of protein synthesis remains unclear. Here, we isolated mutations in 16S rRNA that increase the rate of miscoding and stop codon read-through. Many of the mutations clustered along interfaces between the 30S shoulder domain and other parts of the ribosome, strongly implicating shoulder movement in the induced-fit mechanism of decoding. The largest subset of mutations mapped to helices h8 and h14. These helices interact with each other and with the 50S subunit to form bridge B8. Previous cryo-EM studies revealed a contact between h14 and the switch 1 motif of EF-Tu, raising the possibility that h14 plays a direct role in GTPase activation. To investigate this possibility, we constructed both deletions and insertions in h14. While ribosomes harboring a 2-base-pair (bp) insertion in h14 were completely inactive in vivo, those containing a 2-bp deletion retained activity but were error prone. In vitro, the truncation of h14 accelerated GTP hydrolysis for EF-Tu bearing near-cognate aminoacyl-tRNA, an effect that can largely account for the observed miscoding in vivo. These data show that h14 does not help activate EF-Tu but instead negatively controls GTP hydrolysis by the factor. We propose that bridge B8 normally acts to counter inward rotation of the shoulder domain; hence, mutations in h8 and h14 that compromise this bridge decrease the stringency of aminoacyl-tRNA selection.
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MESH Headings
- Binding Sites/genetics
- Codon, Nonsense
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Kinetics
- Models, Molecular
- Mutation, Missense
- Nucleic Acid Conformation
- Protein Biosynthesis
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Ribosomal, 16S/chemistry
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 16S/metabolism
- RNA, Transfer, Amino Acyl/metabolism
- Ribosomes/genetics
- Ribosomes/metabolism
- Suppression, Genetic
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Affiliation(s)
- Sean P McClory
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
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34
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Abstract
Sixty-one codons specify 20 amino acids, offering cells many options for encoding a polypeptide sequence. Two new studies (Cannarrozzi et al., 2010; Tuller et al., 2010) now foster the idea that patterns of codon usage can control ribosome speed, fine-tuning translation to increase the efficiency of protein synthesis.
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Affiliation(s)
- Kurt Fredrick
- Department of Microbiology, Ohio State Biochemistry Program, and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
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35
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Abstract
In Escherichia coli, translational arrest can elicit cleavage of codons within the ribosomal A site. This A-site mRNA cleavage is independent of RelE, and has been proposed to be an endonucleolytic activity of the ribosome. Here, we show that the 3'-->5' exonuclease RNase II plays an important role in RelE-independent A-site cleavage. Instead of A-site cleavage, translational pausing in DeltaRNase II cells produces transcripts that are truncated +12 and +28 nucleotides downstream of the A-site codon. Deletions of the genes encoding polynucleotide phosphorylase (PNPase) and RNase R had little effect on A-site cleavage. However, PNPase overexpression restored A-site cleavage activity to DeltaRNase II cells. Purified RNase II and PNPase were both unable to directly catalyse A-site cleavage in vitro. Instead, these exonucleases degraded ribosome-bound mRNA to positions +18 and +24 nucleotides downstream of the ribosomal A site respectively. Finally, a stable structural barrier to exoribonuclease activity inhibited A-site cleavage when introduced immediately downstream of paused ribosomes. These results demonstrate that 3'-->5' exonuclease activity is an important prerequisite for efficient A-site cleavage. We propose that RNase II degrades mRNA to the downstream border of paused ribosomes, facilitating cleavage of the A-site codon by an unknown RNase.
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Affiliation(s)
- Fernando Garza-Sánchez
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106-9610, USA
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36
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Abstract
Structural studies have revealed multiple contacts between the ribosomal P site and tRNA, but how these contacts contribute to P-tRNA binding remains unclear. In this study, the effects of ribosomal mutations on the dissociation rate (k(off)) of various tRNAs from the P site were measured. Mutation of the 30S P site destabilized tRNAs to various degrees, depending on the mutation and the species of tRNA. These data support the idea that ribosome-tRNA interactions are idiosyncratically tuned to ensure stable binding of all tRNA species. Unlike deacylated elongator tRNAs, N-acetyl-aminoacyl-tRNAs and tRNA(fMet) dissociated from the P site at a similar low rate, even in the presence of various P-site mutations. These data provide evidence for a stability threshold for P-tRNA binding and suggest that ribosome-tRNA(fMet) interactions are uniquely tuned for tight binding. The effects of 16S rRNA mutation G1338U were suppressed by 50S E-site mutation C2394A, suggesting that G1338 is particularly important for stabilizing tRNA in the P/E site. Finally, mutation C2394A or the presence of an N-acetyl-aminoacyl group slowed the association rate (k(on)) of tRNA dramatically, suggesting that deacylated tRNA binds the P site of the ribosome via the E site.
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Affiliation(s)
- Shinichiro Shoji
- Department of Microbiology, The Ohio State University, 484 W., 12th Ave, Columbus, OH 43210, USA
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37
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Ling J, So BR, Yadavalli SS, Roy H, Shoji S, Fredrick K, Musier-Forsyth K, Ibba M. Resampling and editing of mischarged tRNA prior to translation elongation. Mol Cell 2009; 33:654-60. [PMID: 19285947 DOI: 10.1016/j.molcel.2009.01.031] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 12/10/2008] [Accepted: 01/23/2009] [Indexed: 11/17/2022]
Abstract
Faithful translation of the genetic code depends on the GTPase EF-Tu delivering correctly charged aminoacyl-tRNAs to the ribosome for pairing with cognate codons. The accurate coupling of cognate amino acids and tRNAs by the aminoacyl-tRNA synthetases is achieved through a combination of substrate specificity and product editing. Once released by aminoacyl-tRNA synthetases, both cognate and near-cognate aminoacyl-tRNAs were considered to be committed to ribosomal protein synthesis through their association with EF-Tu. Here we show instead that aminoacyl-tRNAs in ternary complex with EF-Tu*GTP can readily dissociate and rebind to aminoacyl-tRNA synthetases. For mischarged species, this allows resampling by the product editing pathway, leading to a reduction in the overall error rate of aminoacyl-tRNA synthesis. Resampling of mischarged tRNAs was shown to increase the accuracy of translation over ten fold during in vitro protein synthesis, supporting the presence of an additional quality control step prior to translation elongation.
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Affiliation(s)
- Jiqiang Ling
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
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38
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Abstract
Protein synthesis occurs in ribosomes, the targets of numerous antibiotics. How these large and complex machines read and move along mRNA have proven to be challenging questions. In this Review, we focus on translocation, the last step of the elongation cycle in which movement of tRNA and mRNA is catalyzed by elongation factor G. Translocation entails large-scale movements of the tRNAs and conformational changes in the ribosome that require numerous tertiary contacts to be disrupted and reformed. We highlight recent progress toward elucidating the molecular basis of translocation and how various antibiotics influence tRNA-mRNA movement.
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Affiliation(s)
| | | | - Kurt Fredrick
- Department of Microbiology
- Center for RNA Biology
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
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39
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Abstract
The exit (E) site has been implicated in several ribosomal activities, including translocation, decoding, and maintenance of the translational reading frame. Here, we target the 30S subunit E site by introducing a deletion in rpsG that truncates the beta-hairpin of ribosomal protein S7. This mutation (S7DeltaR77-Y84) increases both -1 and +1 frameshifting but does not increase miscoding, providing evidence that the 30S E site plays a specific role in frame maintenance. Mutation S7DeltaR77-Y84 also stimulates +1 programmed frameshifting during prfB'-lacZ translation in many synthetic contexts. However, no effect is seen when the E codon of the frameshift site corresponds to those found in nature, suggesting that E-tRNA release does not normally limit the rate of prfB frameshifting. Ribosomes containing S7DeltaR77-Y84 exhibit an elevated rate of spontaneous reverse translocation and an increased K (1/2) for E-tRNA. These effects are of similar magnitude, suggesting that both result from destabilization of E-tRNA. Finally, this mutation of the 30S E site does not inhibit EF-G-dependent translocation, consistent with a primary role for the 50S E site in the mechanism.
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Affiliation(s)
- Aishwarya Devaraj
- Ohio State Biochemistry Program, The Ohio State University, Columbus, 43210, USA
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40
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Abstract
Initiation of translation involves recognition of the start codon by the initiator tRNA in the 30S subunit. To investigate the role of ribosomal RNA (rRNA) in this process, we isolated a number of 16S rRNA mutations that increase translation from the non-canonical start codon AUC. These mutations cluster to distinct regions that overlap remarkably well with previously identified class III protection sites and implicate both IF1 and IF3 in start codon selection. Two mutations map to the 790 loop and presumably act by inhibiting IF3 binding. Another cluster of mutations surrounds the conserved A1413(o)G1487 base pair of helix 44 in a region known to be distorted by IF1 and IF3. Site-directed mutagenesis in this region confirmed that this factor-induced rearrangement of helix 44 helps regulate initiation fidelity. A third cluster of mutations maps to the neck of the 30S subunit, suggesting that the dynamics of the head domain influences translation initiation. In addition to identifying mutations that decrease fidelity, we found that many P-site mutations increase the stringency of start codon selection. These data provide evidence that the interaction between the initiator tRNA and the 30S P site is tuned to balance efficiency and accuracy during initiation.
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Affiliation(s)
- Daoming Qin
- Ohio State Biochemistry Program, The OhioState University, OH 43210, USA
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41
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Borovinskaya MA, Shoji S, Fredrick K, Cate JHD. Structural basis for hygromycin B inhibition of protein biosynthesis. RNA 2008; 14:1590-9. [PMID: 18567815 PMCID: PMC2491480 DOI: 10.1261/rna.1076908] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Accepted: 05/07/2008] [Indexed: 05/18/2023]
Abstract
Aminoglycosides are one of the most widely used and clinically important classes of antibiotics that target the ribosome. Hygromycin B is an atypical aminoglycoside antibiotic with unique structural and functional properties. Here we describe the structure of the intact Escherichia coli 70S ribosome in complex with hygromycin B. The antibiotic binds to the mRNA decoding center in the small (30S) ribosomal subunit of the 70S ribosome and induces a localized conformational change, in contrast to its effects observed in the structure of the isolated 30S ribosomal subunit in complex with the drug. The conformational change in the ribosome caused by hygromycin B binding differs from that induced by other aminoglycosides. Also, in contrast to other aminoglycosides, hygromycin B potently inhibits spontaneous reverse translocation of tRNAs and mRNA on the ribosome in vitro. These structural and biochemical results help to explain the unique mode of translation inhibition by hygromycin B.
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Affiliation(s)
- Maria A Borovinskaya
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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42
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Abstract
In the cell, the activity of tRNA is governed by its acylation state. Interactions with the ribosome, translation factors, and regulatory elements are strongly influenced by the acyl group, and presumably other cellular components that interact with tRNA also use the acyl group as a specificity determinant. Thus, those using biochemical approaches to study any aspect of tRNA biology should be familiar with effective methods to prepare and evaluate acylated tRNA reagents. Here, methods to prepare aminoacyl-tRNA, N-acetyl-aminoacyl-tRNA, and fMet-tRNA(fMet) and to assess their homogeneity are described. Using these methods, acylated tRNAs of high homogeneity can be reliably obtained.
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Affiliation(s)
- Sarah E Walker
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
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43
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Cate JHD, Borovinskaya MA, Pai RD, Zhang W, Schuwirth BS, Holton JM, Hirokawa G, Kaji H, Kaji A, Shoji S, Fredrick K. Structures of the E. coli ribosome with ribosome recycling factor and antibiotics. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.398.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jamie HD Cate
- Chemistry and Molecular and Cell Biology
- Physical Biosciences DivisionLawrence Berkeley National LaboratoryBerkeleyCA
| | | | - Raj D Pai
- Molecular and Cell BiologyUniversity of CaliforniaBerkeleyCA
| | - Wen Zhang
- Molecular and Cell BiologyUniversity of CaliforniaBerkeleyCA
| | - Barbara S Schuwirth
- Cancer research UK Clare Hall LaboratoriesLondon Research InstituteLondonUnited Kingdom
| | - James M Holton
- Biochemistry and BiophysicsUniversity of CaliforniaSan FranciscoCA
- Physical Biosciences DivisionLawrence Berkeley National LaboratoryBerkeleyCA
| | - Go Hirokawa
- National Cardiovascular Center Research InstituteOsakaJapan
| | - Hideko Kaji
- Biochemistry and Molecular BiologyThomas Jefferson UniversityPhiladelphiaPA
| | - Akira Kaji
- MicrobiologyUniversity of Pennsylvania School of MedicinePhiladelphiaPA
| | | | - Kurt Fredrick
- Ohio State Biochemistry ProgramThe Ohio State UniversityColumbusOH
- Microbiology
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44
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Abstract
In bacteria, initiation of translation is kinetically controlled by factors IF1, IF2, and IF3, which work in conjunction with the 30S subunit to ensure accurate selection of the initiator tRNA (fMet-tRNA(fMet)) and the start codon. Here, we show that mutations G1338A and A790G of 16S rRNA decrease initiation fidelity in vivo and do so in distinct ways. Mutation G1338A increases the affinity of tRNA(fMet) for the 30S subunit, suggesting that G1338 normally forms a suboptimal Type II interaction with fMet-tRNA(fMet). By stabilizing fMet-tRNA(fMet) in the preinitiation complex, G1338A may partially compensate for mismatches in the codon-anti-codon helix and thereby increase spurious initiation. Unlike G1338A, A790G decreases the affinity of IF3 for the 30S subunit. This may indirectly stabilize fMet-tRNA(fMet) in the preinitiation complex and/or promote premature docking of the 50S subunit, resulting in increased levels of spurious initiation.
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Affiliation(s)
- Daoming Qin
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, USA
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45
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Ling J, Roy H, Qin D, Rubio MAT, Alfonzo JD, Fredrick K, Ibba M. Pathogenic mechanism of a human mitochondrial tRNAPhe mutation associated with myoclonic epilepsy with ragged red fibers syndrome. Proc Natl Acad Sci U S A 2007; 104:15299-304. [PMID: 17878308 PMCID: PMC2000536 DOI: 10.1073/pnas.0704441104] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Indexed: 11/18/2022] Open
Abstract
Human mitochondrial tRNA (hmt-tRNA) mutations are associated with a variety of diseases including mitochondrial myopathies, diabetes, encephalopathies, and deafness. Because the current understanding of the precise molecular mechanisms of these mutations is limited, there is no efficient method to treat their associated mitochondrial diseases. Here, we use a variety of known mutations in hmt-tRNA(Phe) to investigate the mechanisms that lead to malfunctions. We tested the impact of hmt-tRNA(Phe) mutations on aminoacylation, structure, and translation elongation-factor binding. The majority of the mutants were pleiotropic, exhibiting defects in aminoacylation, global structure, and elongation-factor binding. One notable exception was the G34A anticodon mutation of hmt-tRNA(Phe) (mitochondrial DNA mutation G611A), which is associated with MERRF (myoclonic epilepsy with ragged red fibers). In vitro, the G34A mutation decreases aminoacylation activity by 100-fold, but does not affect global folding or recognition by elongation factor. Furthermore, G34A hmt-tRNA(Phe) does not undergo adenosine-to-inosine (A-to-I) editing, ruling out miscoding as a possible mechanism for mitochondrial malfunction. To improve the aminoacylation state of the mutant tRNA, we modified the tRNA binding domain of the nucleus-encoded human mitochondrial phenylalanyl-tRNA synthetase, which aminoacylates hmt-tRNA(Phe) with cognate phenylalanine. This variant enzyme displayed significantly improved aminoacylation efficiency for the G34A mutant, suggesting a general strategy to treat certain classes of mitochondrial diseases by modification of the corresponding nuclear gene.
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Affiliation(s)
| | - Hervé Roy
- Department of Microbiology, and
- Ohio State RNA Group, Ohio State University, Columbus, OH 43210
| | | | - Mary Anne T. Rubio
- Department of Microbiology, and
- Ohio State RNA Group, Ohio State University, Columbus, OH 43210
| | - Juan D. Alfonzo
- *Ohio State Biochemistry Program
- Department of Microbiology, and
- Ohio State RNA Group, Ohio State University, Columbus, OH 43210
| | - Kurt Fredrick
- *Ohio State Biochemistry Program
- Department of Microbiology, and
- Ohio State RNA Group, Ohio State University, Columbus, OH 43210
| | - Michael Ibba
- *Ohio State Biochemistry Program
- Department of Microbiology, and
- Ohio State RNA Group, Ohio State University, Columbus, OH 43210
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46
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Abstract
The widely used antibiotic spectinomycin inhibits bacterial protein synthesis by blocking translocation of messenger RNA and transfer RNAs on the ribosome. Here, we show that in crystals of the Escherichia coli 70S ribosome spectinomycin binding traps a distinct swiveling state of the head domain of the small ribosomal subunit. Spectinomycin also alters the rate and completeness of reverse translocation in vitro. These structural and biochemical data indicate that in solution spectinomycin sterically blocks swiveling of the head domain of the small ribosomal subunit and thereby disrupts the translocation cycle.
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Affiliation(s)
- Maria A. Borovinskaya
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Shinichiro Shoji
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
| | - James M. Holton
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
| | - Jamie H. D. Cate
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Department of Chemistry, University of California, Berkeley, California 94720
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
- Corresponding author,
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47
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Abstract
A widely held view is that directional movement of tRNA in the ribosome is determined by an intrinsic mechanism and driven thermodynamically by transpeptidation. Here, we show that, in certain ribosomal complexes, the pretranslocation (PRE) state is thermodynamically favored over the posttranslocation (POST) state. Spontaneous and efficient conversion from the POST to PRE state is observed when EF-G is depleted from ribosomes in the POST state or when tRNA is added to the E site of ribosomes containing P-site tRNA. In the latter assay, the rate of tRNA movement is increased by streptomycin and neomycin, decreased by tetracycline, and not affected by the acylation state of the tRNA. In one case, we provide evidence that complex conversion occurs by reverse translocation (i.e., direct movement of the tRNAs from the E and P sites to the P and A sites, respectively). These findings have important implications for the energetics of translocation.
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Affiliation(s)
- Shinichiro Shoji
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
| | - Sarah E. Walker
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
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48
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Tram U, Fredrick K, Werren JH, Sullivan W. Paternal chromosome segregation during the first mitotic division determines Wolbachia-induced cytoplasmic incompatibility phenotype. J Cell Sci 2006; 119:3655-63. [PMID: 16912076 DOI: 10.1242/jcs.03095] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The most common Wolbachia-induced phenotype in insects is cytoplasmic incompatibility (CI), which occurs when sperm from infected males fertilize eggs from uninfected females. CI produces distinct phenotypes in three closely related haplo-diploid species of the genus Nasonia: mortality in N. longicornis and N. giraulti, and conversion to male development in N. vitripennis. We demonstrate that the majority of CI-induced mortality occurs during embryogenesis and that the pattern of paternal chromosome segregation during the first mitosis is a good predictor of CI phenotype. In N. giraulti and N. longicornis, the paternal chromosomes mis-segregate, producing abnormal nuclei connected by chromatin bridges. Consequently, these embryos arrest development with very few and abnormal nuclei. In contrast, the paternal genome in N. vitripennis is either not segregated or mis-segregates to one of the two daughter nuclei. Consequently, these embryos continue development utilizing the maternally derived haploid nuclei, resulting in male offspring. The latter class is the first documented example of asymmetric mitotic segregation of abnormal chromosomes. We conclude that in haplo-diploids, CI-induced embryonic lethality occurs only when abnormal paternal genome segregation affects both products of the first mitotic division. This is the first study to associate differences in types of CI with specific cytological defects.
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Affiliation(s)
- Uyen Tram
- University of California, Santa Cruz, Molecular, Cellular, and Developmental Biology, 319 Sinsheimer Laboratories, Santa Cruz, CA 95064, USA.
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49
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Walker SE, Fredrick K. Recognition and positioning of mRNA in the ribosome by tRNAs with expanded anticodons. J Mol Biol 2006; 360:599-609. [PMID: 16730356 PMCID: PMC2602952 DOI: 10.1016/j.jmb.2006.05.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 04/28/2006] [Accepted: 05/01/2006] [Indexed: 10/24/2022]
Abstract
Mutant tRNAs containing an extra nucleotide in the anticodon loop are known to suppress +1 frameshift mutations, but in no case has the molecular mechanism been clarified. It has been proposed that the expanded anticodon pairs with a complementary mRNA sequence (the frameshift sequence) in the A site, and this quadruplet "codon-anticodon" helix is translocated to the P site to restore the correct reading frame. Here, we analyze the ability of tRNA analogs containing expanded anticodons to recognize and position mRNA in ribosomal complexes in vitro. In all cases tested, 8 nt anticodon loops position the 3' three-quarters of the frameshift sequence in the P site, indicating that the 5' bases of the expanded anticodon (nucleotides 33.5, 34, and 35) pair with mRNA in the P site. We also provide evidence that four base-pairs can form between the P-site tRNA and mRNA, and the fourth base-pair involves nucleotide 36 of the tRNA and lies toward (or in) the 30 S E site. In the A site, tRNA analogs with the expanded anticodon ACCG are able to recognize either CGG or GGU. These data imply a flexibility of the expanded anticodon in the A site. Recognition of the 5' three-quarters of the frameshift sequence in the A site and subsequent translocation of the expanded anticodon to the P site results in movement of mRNA by four nucleotides, explaining how these tRNAs can change the mRNA register in the ribosome to restore the correct reading frame.
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Affiliation(s)
- Sarah E. Walker
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
- Corresponding author E-mail address of the corresponding author:
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50
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McGarry KG, Walker SE, Wang H, Fredrick K. Destabilization of the P site codon-anticodon helix results from movement of tRNA into the P/E hybrid state within the ribosome. Mol Cell 2006; 20:613-22. [PMID: 16307924 PMCID: PMC2631382 DOI: 10.1016/j.molcel.2005.10.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2005] [Revised: 08/02/2005] [Accepted: 10/05/2005] [Indexed: 10/25/2022]
Abstract
Retention of the reading frame in ribosomal complexes after single-round translocation depends on the acylation state of the tRNA. When tRNA lacking a peptidyl group is translocated to the P site, the mRNA slips to allow re-pairing of the tRNA with a nearby out-of-frame codon. Here, we show that this ribosomal activity results from movement of tRNA into the P/E hybrid state. Slippage of mRNA is suppressed by 3' truncation of the translocated tRNA, increased MgCl2 concentration, and mutation C2394A of the 50S E site, and each of these conditions inhibits P/E-state formation. Mutation G2252U of the 50S P site stimulates mRNA slippage, suggesting that decreased affinity of tRNA for the P/P state also destabilizes mRNA in the complex. The effects of G2252U are suppressed by C2394A, further implicating the P/E state in mRNA destabilization. This work uncovers a functional attribute of the P/E state crucial for understanding translation.
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Affiliation(s)
- Kevin G. McGarry
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
| | - Sarah E. Walker
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
| | - Huanyu Wang
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210
- Correspondence:
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