1
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Szekely O, Rangadurai AK, Gu S, Manghrani A, Guseva S, Al-Hashimi HM. NMR measurements of transient low-populated tautomeric and anionic Watson-Crick-like G·T/U in RNA:DNA hybrids: implications for the fidelity of transcription and CRISPR/Cas9 gene editing. Nucleic Acids Res 2024; 52:2672-2685. [PMID: 38281263 PMCID: PMC10954477 DOI: 10.1093/nar/gkae027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/02/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024] Open
Abstract
Many biochemical processes use the Watson-Crick geometry to distinguish correct from incorrect base pairing. However, on rare occasions, mismatches such as G·T/U can transiently adopt Watson-Crick-like conformations through tautomerization or ionization of the bases, giving rise to replicative and translational errors. The propensities to form Watson-Crick-like mismatches in RNA:DNA hybrids remain unknown, making it unclear whether they can also contribute to errors during processes such as transcription and CRISPR/Cas editing. Here, using NMR R1ρ experiments, we show that dG·rU and dT·rG mismatches in two RNA:DNA hybrids transiently form tautomeric (Genol·T/U $ \mathbin{\lower.3ex\hbox{$\buildrel\textstyle\rightarrow\over {\smash{\leftarrow}\vphantom{_{\vbox to.5ex{\vss}}}}$}}$ G·Tenol/Uenol) and anionic (G·T-/U-) Watson-Crick-like conformations. The tautomerization dynamics were like those measured in A-RNA and B-DNA duplexes. However, anionic dG·rU- formed with a ten-fold higher propensity relative to dT-·rG and dG·dT- and this could be attributed to the lower pKa (ΔpKa ∼0.4-0.9) of U versus T. Our findings suggest plausible roles for Watson-Crick-like G·T/U mismatches in transcriptional errors and CRISPR/Cas9 off-target gene editing, uncover a crucial difference between the chemical dynamics of G·U versus G·T, and indicate that anionic Watson-Crick-like G·U- could play a significant role evading Watson-Crick fidelity checkpoints in RNA:DNA hybrids and RNA duplexes.
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Affiliation(s)
- Or Szekely
- Department of Biology, Duke University, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Duke University, Durham, NC 27710, USA
| | | | - Stephanie Gu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Akanksha Manghrani
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Serafima Guseva
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry and Molecular Biophysics, Columbia University, NY, NY 10032, USA
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2
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Landerer C, Poehls J, Toth-Petroczy A. Fitness Effects of Phenotypic Mutations at Proteome-Scale Reveal Optimality of Translation Machinery. Mol Biol Evol 2024; 41:msae048. [PMID: 38421032 PMCID: PMC10939442 DOI: 10.1093/molbev/msae048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 01/30/2024] [Accepted: 02/23/2024] [Indexed: 03/02/2024] Open
Abstract
Errors in protein translation can lead to non-genetic, phenotypic mutations, including amino acid misincorporations. While phenotypic mutations can increase protein diversity, the systematic characterization of their proteome-wide frequencies and their evolutionary impact has been lacking. Here, we developed a mechanistic model of translation errors to investigate how selection acts on protein populations produced by amino acid misincorporations. We fitted the model to empirical observations of misincorporations obtained from over a hundred mass spectrometry datasets of E. coli and S. cerevisiae. We found that on average 20% to 23% of proteins synthesized in the cell are expected to harbor at least one amino acid misincorporation, and that deleterious misincorporations are less likely to occur. Combining misincorporation probabilities and the estimated fitness effects of amino acid substitutions in a population genetics framework, we found 74% of mistranslation events in E. coli and 94% in S. cerevisiae to be neutral. We further show that the set of available synonymous tRNAs is subject to evolutionary pressure, as the presence of missing tRNAs would increase codon-anticodon cross-reactivity and misincorporation error rates. Overall, we find that the translation machinery is likely optimal in E. coli and S. cerevisiae and that both local solutions at the level of codons and a global solution such as the tRNA pool can mitigate the impact of translation errors. We provide a framework to study the evolutionary impact of codon-specific translation errors and a method for their proteome-wide detection across organisms and conditions.
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Affiliation(s)
- Cedric Landerer
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Jonas Poehls
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
| | - Agnes Toth-Petroczy
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01062 Dresden, Germany
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3
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Szekely O, Rangadurai AK, Gu S, Manghrani A, Guseva S, Al-Hashimi HM. NMR measurements of transient low-populated tautomeric and anionic Watson-Crick-like G·T/U in RNA:DNA hybrids: Implications for the fidelity of transcription and CRISPR/Cas9 gene editing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.24.554670. [PMID: 37662220 PMCID: PMC10473728 DOI: 10.1101/2023.08.24.554670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Many biochemical processes use the Watson-Crick geometry to distinguish correct from incorrect base pairing. However, on rare occasions, mismatches such as G•T/U can transiently adopt Watson-Crick-like conformations through tautomerization or ionization of the bases, giving rise to replicative and translational errors. The propensities to form Watson-Crick-like mismatches in RNA:DNA hybrids remain unknown, making it unclear whether they can also contribute to errors during processes such as transcription and CRISPR/Cas editing. Here, using NMR R 1ρ experiments, we show that dG•rU and dT•rG mismatches in two RNA:DNA hybrids transiently form tautomeric (G enol •T/U ⇄G•T enol /U enol ) and anionic (G•T - /U - ) Watson-Crick-like conformations. The tautomerization dynamics were like those measured in A-RNA and B-DNA duplexes. However, anionic dG•rU - formed with a ten-fold higher propensity relative to dT - •rG and dG•dT - and this could be attributed to the lower pK a (Δ pK a ∼0.4-0.9) of U versus T. Our findings suggest plausible roles for Watson-Crick-like G•T/U mismatches in transcriptional errors and CRISPR/Cas9 off-target gene editing, uncover a crucial difference between the chemical dynamics of G•U versus G•T, and indicate that anionic Watson-Crick-like G•U - could play a significant role evading Watson-Crick fidelity checkpoints in RNA:DNA hybrids and RNA duplexes.
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4
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Romero Romero ML, Landerer C, Poehls J, Toth‐Petroczy A. Phenotypic mutations contribute to protein diversity and shape protein evolution. Protein Sci 2022; 31:e4397. [PMID: 36040266 PMCID: PMC9375231 DOI: 10.1002/pro.4397] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/14/2022] [Accepted: 07/04/2022] [Indexed: 11/16/2022]
Abstract
Errors in DNA replication generate genetic mutations, while errors in transcription and translation lead to phenotypic mutations. Phenotypic mutations are orders of magnitude more frequent than genetic ones, yet they are less understood. Here, we review the types of phenotypic mutations, their quantifications, and their role in protein evolution and disease. The diversity generated by phenotypic mutation can facilitate adaptive evolution. Indeed, phenotypic mutations, such as ribosomal frameshift and stop codon readthrough, sometimes serve to regulate protein expression and function. Phenotypic mutations have often been linked to fitness decrease and diseases. Thus, understanding the protein heterogeneity and phenotypic diversity caused by phenotypic mutations will advance our understanding of protein evolution and have implications on human health and diseases.
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Affiliation(s)
- Maria Luisa Romero Romero
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden Germany
- Center for Systems Biology Dresden Dresden Germany
| | - Cedric Landerer
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden Germany
- Center for Systems Biology Dresden Dresden Germany
| | - Jonas Poehls
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden Germany
- Center for Systems Biology Dresden Dresden Germany
| | - Agnes Toth‐Petroczy
- Max Planck Institute of Molecular Cell Biology and Genetics Dresden Germany
- Center for Systems Biology Dresden Dresden Germany
- Cluster of Excellence Physics of Life TU Dresden Dresden Germany
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5
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Jayaraman V, Toledo‐Patiño S, Noda‐García L, Laurino P. Mechanisms of protein evolution. Protein Sci 2022; 31:e4362. [PMID: 35762715 PMCID: PMC9214755 DOI: 10.1002/pro.4362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/11/2022] [Accepted: 05/14/2022] [Indexed: 11/06/2022]
Abstract
How do proteins evolve? How do changes in sequence mediate changes in protein structure, and in turn in function? This question has multiple angles, ranging from biochemistry and biophysics to evolutionary biology. This review provides a brief integrated view of some key mechanistic aspects of protein evolution. First, we explain how protein evolution is primarily driven by randomly acquired genetic mutations and selection for function, and how these mutations can even give rise to completely new folds. Then, we also comment on how phenotypic protein variability, including promiscuity, transcriptional and translational errors, may also accelerate this process, possibly via "plasticity-first" mechanisms. Finally, we highlight open questions in the field of protein evolution, with respect to the emergence of more sophisticated protein systems such as protein complexes, pathways, and the emergence of pre-LUCA enzymes.
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Affiliation(s)
- Vijay Jayaraman
- Department of Molecular Cell BiologyWeizmann Institute of ScienceRehovotIsrael
| | - Saacnicteh Toledo‐Patiño
- Protein Engineering and Evolution UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
| | - Lianet Noda‐García
- Department of Plant Pathology and Microbiology, Institute of Environmental Sciences, Robert H. Smith Faculty of Agriculture, Food and EnvironmentHebrew University of JerusalemRehovotIsrael
| | - Paola Laurino
- Protein Engineering and Evolution UnitOkinawa Institute of Science and Technology Graduate UniversityOkinawaJapan
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6
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Kędzior M, Garcia AK, Li M, Taton A, Adam ZR, Young JN, Kaçar B. Resurrected Rubisco suggests uniform carbon isotope signatures over geologic time. Cell Rep 2022; 39:110726. [PMID: 35476992 DOI: 10.1016/j.celrep.2022.110726] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/26/2022] [Accepted: 03/30/2022] [Indexed: 11/30/2022] Open
Abstract
The earliest geochemical indicators of microbes-and the enzymes that powered them-extend back ∼3.8 Ga on Earth. Paleobiologists often attempt to understand these indicators by assuming that the behaviors of extant microbes and enzymes are uniform with those of their predecessors. This consistency in behavior seems at odds with our understanding of the inherent variability of living systems. Here, we examine whether a uniformitarian assumption for an enzyme thought to generate carbon isotope indicators of biological activity, RuBisCO, can be corroborated by independently studying the history of changes recorded within RuBisCO's genetic sequences. We resurrected a Precambrian-age RuBisCO by engineering its ancient DNA inside a cyanobacterium genome and measured the engineered organism's fitness and carbon-isotope-discrimination profile. Results indicate that Precambrian uniformitarian assumptions may be warranted but with important caveats. Experimental studies illuminating early innovations are crucial to explore the molecular foundations of life's earliest traces.
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Affiliation(s)
- Mateusz Kędzior
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA; NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Amanda K Garcia
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA; NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Meng Li
- School of Oceanography, University of Washington, Seattle, WA 98195, USA
| | - Arnaud Taton
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zachary R Adam
- NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Geosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jodi N Young
- School of Oceanography, University of Washington, Seattle, WA 98195, USA
| | - Betül Kaçar
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA; NASA Center for Early Life and Evolution, University of Wisconsin-Madison, Madison, WI 53706, USA.
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7
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Jackson C, Toth-Petroczy A, Kolodny R, Hollfelder F, Fuxreiter M, Caroline Lynn Kamerlin S, Tokuriki N. Adventures on the routes of protein evolution — in memoriam Dan Salah Tawfik (1955 - 2021). J Mol Biol 2022; 434:167462. [DOI: 10.1016/j.jmb.2022.167462] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 01/17/2022] [Indexed: 12/21/2022]
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8
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Zheng J, Guo N, Wagner A. Mistranslation reduces mutation load in evolving proteins through negative epistasis with DNA mutations. Mol Biol Evol 2021; 38:4792-4804. [PMID: 34255074 PMCID: PMC8557407 DOI: 10.1093/molbev/msab206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Translational errors during protein synthesis cause phenotypic mutations that are several orders of magnitude more frequent than DNA mutations. Such phenotypic mutations may affect adaptive evolution through their interactions with DNA mutations. To study how mistranslation may affect the adaptive evolution of evolving proteins, we evolved populations of green fluorescent protein (GFP) in either high-mistranslation or low-mistranslation Escherichia coli hosts. In both hosts, we first evolved GFP under purifying selection for the ancestral phenotype green fluorescence, and then under directional selection toward the new phenotype yellow fluorescence. High-mistranslation populations evolved modestly higher yellow fluorescence during each generation of evolution than low-mistranslation populations. We demonstrate by high-throughput sequencing that elevated mistranslation reduced the accumulation of deleterious DNA mutations under both purifying and directional selection. It did so by amplifying the fitness effects of deleterious DNA mutations through negative epistasis with phenotypic mutations. In contrast, mistranslation did not affect the incidence of beneficial mutations. Our findings show that phenotypic mutations interact epistatically with DNA mutations. By reducing a population’s mutation load, mistranslation can affect an important determinant of evolvability.
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Affiliation(s)
- Jia Zheng
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Swiss Institute of Bioinformatics, Quartier Sorge-Batiment Genopode, Lausanne, Switzerland
| | - Ning Guo
- Zwirnereistrasse 11, Wallisellen, Zurich, Switzerland
| | - Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.,Swiss Institute of Bioinformatics, Quartier Sorge-Batiment Genopode, Lausanne, Switzerland.,The Santa Fe Institute, Santa Fe, New Mexico, USA
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9
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Moran J, Finlay D, Tikhonov M. Improve it or lose it: Evolvability cost of competition for expression. Phys Rev E 2021; 103:062402. [PMID: 34271680 DOI: 10.1103/physreve.103.062402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 05/24/2021] [Indexed: 11/07/2022]
Abstract
Expression level is known to be a strong determinant of a protein's rate of evolution. But the converse can also be true: evolutionary dynamics can affect expression levels of proteins. Having implications in both directions fosters the possibility of an "improve it or lose it" feedback loop, where higher expressed systems are more likely to improve and be expressed even higher, while those that are expressed less are eventually lost to drift. Using a minimal model to study this in the context of a changing environment, we demonstrate that one unexpected consequence of such a feedback loop is that a slow switch to a new environment can allow genotypes to reach higher fitness sooner than a direct exposure to it.
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Affiliation(s)
- Jacob Moran
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Devon Finlay
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Mikhail Tikhonov
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri 63130, USA
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10
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Luzon-Hidalgo R, Risso VA, Delgado A, Andrés-León E, Ibarra-Molero B, Sanchez-Ruiz JM. Evidence for a role of phenotypic mutations in virus adaptation. iScience 2021; 24:102257. [PMID: 33817569 PMCID: PMC8010470 DOI: 10.1016/j.isci.2021.102257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/22/2021] [Accepted: 02/26/2021] [Indexed: 12/12/2022] Open
Abstract
Viruses interact extensively with the host molecular machinery, but the underlying mechanisms are poorly understood. Bacteriophage T7 recruits the small protein thioredoxin of the Escherichia coli host as an essential processivity factor for the viral DNA polymerase. We challenged the phage to propagate in a host in which thioredoxin had been extensively modified to hamper its recruitment. The virus adapted to the engineered host without losing the capability to propagate in the original host, but no genetic mutations were fixed in the thioredoxin binding domain of the viral DNA polymerase. Virus adaptation correlated with mutations in the viral RNA polymerase, supporting that promiscuous thioredoxin recruitment was enabled by phenotypic mutations caused by transcription errors. These results point to a mechanism of virus adaptation that may play a role in cross-species transmission. We propose that phenotypic mutations may generally contribute to the capability of viruses to evade antiviral strategies. Phage adapts to a host modified to hinder the essential recruitment of a host protein No genetic mutations are fixed at the engineered virus-host interaction interface Adaptation is likely linked to phenotypic mutations caused by transcription errors Sub-genomic RNAs may enable this kind of adaptation mechanism in coronaviruses
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Affiliation(s)
- Raquel Luzon-Hidalgo
- Departamento de Quimica Fisica. Facultad de Ciencias, Unidad de Excelencia de Quimica Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, Granada 18071, Spain
| | - Valeria A Risso
- Departamento de Quimica Fisica. Facultad de Ciencias, Unidad de Excelencia de Quimica Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, Granada 18071, Spain
| | - Asuncion Delgado
- Departamento de Quimica Fisica. Facultad de Ciencias, Unidad de Excelencia de Quimica Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, Granada 18071, Spain
| | - Eduardo Andrés-León
- Unidad de Bioinformática. Instituto de Parasitología y Biomedicina "López Neyra", CSIC, Armilla, Granada 18016, Spain
| | - Beatriz Ibarra-Molero
- Departamento de Quimica Fisica. Facultad de Ciencias, Unidad de Excelencia de Quimica Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, Granada 18071, Spain
| | - Jose M Sanchez-Ruiz
- Departamento de Quimica Fisica. Facultad de Ciencias, Unidad de Excelencia de Quimica Aplicada a Biomedicina y Medioambiente (UEQ), Universidad de Granada, Granada 18071, Spain
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11
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Usmanova DR, Plata G, Vitkup D. The Relationship between the Misfolding Avoidance Hypothesis and Protein Evolutionary Rates in the Light of Empirical Evidence. Genome Biol Evol 2021; 13:6081017. [PMID: 33432359 PMCID: PMC7874998 DOI: 10.1093/gbe/evab006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2021] [Indexed: 12/14/2022] Open
Abstract
For more than a decade, the misfolding avoidance hypothesis (MAH) and related theories have dominated evolutionary discussions aimed at explaining the variance of the molecular clock across cellular proteins. In this study, we use various experimental data to further investigate the consistency of the MAH predictions with empirical evidence. We also critically discuss experimental results that motivated the MAH development and that are often viewed as evidence of its major contribution to the variability of protein evolutionary rates. We demonstrate, in Escherichia coli and Homo sapiens, the lack of a substantial negative correlation between protein evolutionary rates and Gibbs free energies of unfolding, a direct measure of protein stability. We then analyze multiple new genome-scale data sets characterizing protein aggregation and interaction propensities, the properties that are likely optimized in evolution to alleviate deleterious effects associated with toxic protein misfolding and misinteractions. Our results demonstrate that the propensity of proteins to aggregate, the fraction of charged amino acids, and protein stickiness do correlate with protein abundances. Nevertheless, across multiple organisms and various data sets we do not observe substantial correlations between proteins’ aggregation- and stability-related properties and evolutionary rates. Therefore, diverse empirical data support the conclusion that the MAH and similar hypotheses do not play a major role in mediating a strong negative correlation between protein expression and the molecular clock, and thus in explaining the variability of evolutionary rates across cellular proteins.
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Affiliation(s)
- Dinara R Usmanova
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Germán Plata
- Department of Systems Biology, Columbia University, New York, NY, USA.,Elanco Animal Health, Greenfield, IN, USA
| | - Dennis Vitkup
- Department of Systems Biology, Columbia University, New York, NY, USA.,Department of Biomedical Informatics, Columbia University, New York, NY, USA
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12
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The Boggarts of biology: how non-genetic changes influence the genotype. Curr Genet 2020; 67:65-77. [PMID: 33037901 DOI: 10.1007/s00294-020-01108-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 01/21/2023]
Abstract
The notion that there is a one-one mapping from genotype to phenotype was overturned a long time ago. Along with genotype and environment, 'non-genetic changes' orchestrated by altered RNA and protein molecules also guide the development of phenotype. The idea that there is a route through which changes in phenotype can lead to changes in genotype impinges on several phenomena of molecular, developmental, evolutionary and applied interest. Phenotypic changes that do not alter the underlying DNA sequence have been studied across model systems (eg: DNA and histone modifications, RNA editing, prion formation) and are known to play an important role in short-term adaptation. However, because of their transient nature and unstable inheritance, the role of such changes in long-term evolution has remained controversial. I classify and review three ways in which non-genetic changes can influence genotype and impact cellular fitness across generations, with an emphasis on the enticing idea that they may act as stepping stones for genetic adaptation. I focus on work from microbial systems and attempt to highlight recent experiments and models that bear on this idea. Overall, I review evidence which suggests that non-genetic changes can impact phenotype via their influence on the genotype, and thus play a role in evolutionary change.
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13
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Babkova P, Dunajova Z, Chaloupkova R, Damborsky J, Bednar D, Marek M. Structures of hyperstable ancestral haloalkane dehalogenases show restricted conformational dynamics. Comput Struct Biotechnol J 2020; 18:1497-1508. [PMID: 32637047 PMCID: PMC7327271 DOI: 10.1016/j.csbj.2020.06.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 12/30/2022] Open
Abstract
Ancestral sequence reconstruction is a powerful method for inferring ancestors of modern enzymes and for studying structure-function relationships of enzymes. We have previously applied this approach to haloalkane dehalogenases (HLDs) from the subfamily HLD-II and obtained thermodynamically highly stabilized enzymes (ΔT m up to 24 °C), showing improved catalytic properties. Here we combined crystallographic structural analysis and computational molecular dynamics simulations to gain insight into the mechanisms by which ancestral HLDs became more robust enzymes with novel catalytic properties. Reconstructed ancestors exhibited similar structure topology as their descendants with the exception of a few loop deviations. Strikingly, molecular dynamics simulations revealed restricted conformational dynamics of ancestral enzymes, which prefer a single state, in contrast to modern enzymes adopting two different conformational states. The restricted dynamics can potentially be linked to their exceptional stabilization. The study provides molecular insights into protein stabilization due to ancestral sequence reconstruction, which is becoming a widely used approach for obtaining robust protein catalysts.
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Affiliation(s)
- Petra Babkova
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Bld. A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
| | - Zuzana Dunajova
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Bld. A13, 625 00 Brno, Czech Republic
| | - Radka Chaloupkova
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Bld. A13, 625 00 Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Bld. A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
| | - David Bednar
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Bld. A13, 625 00 Brno, Czech Republic
- International Clinical Research Center, St. Anne's University Hospital Brno, Pekarska 53, 656 91 Brno, Czech Republic
| | - Martin Marek
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, Kamenice 5, Bld. A13, 625 00 Brno, Czech Republic
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14
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Fantini M, Lisi S, De Los Rios P, Cattaneo A, Pastore A. Protein Structural Information and Evolutionary Landscape by In Vitro Evolution. Mol Biol Evol 2020; 37:1179-1192. [PMID: 31670785 PMCID: PMC7086169 DOI: 10.1093/molbev/msz256] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Protein structure is tightly intertwined with function according to the laws of evolution. Understanding how structure determines function has been the aim of structural biology for decades. Here, we have wondered instead whether it is possible to exploit the function for which a protein was evolutionary selected to gain information on protein structure and on the landscape explored during the early stages of molecular and natural evolution. To answer to this question, we developed a new methodology, which we named CAMELS (Coupling Analysis by Molecular Evolution Library Sequencing), that is able to obtain the in vitro evolution of a protein from an artificial selection based on function. We were able to observe with CAMELS many features of the TEM-1 beta-lactamase local fold exclusively by generating and sequencing large libraries of mutational variants. We demonstrated that we can, whenever a functional phenotypic selection of a protein is available, sketch the structural and evolutionary landscape of a protein without utilizing purified proteins, collecting physical measurements, or relying on the pool of natural protein variants.
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Affiliation(s)
- Marco Fantini
- BioSNS Laboratory of Biology, Scuola Normale Superiore (SNS), Pisa, Italy
| | - Simonetta Lisi
- BioSNS Laboratory of Biology, Scuola Normale Superiore (SNS), Pisa, Italy
| | - Paolo De Los Rios
- Institute of Physics, School of Basic Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Antonino Cattaneo
- BioSNS Laboratory of Biology, Scuola Normale Superiore (SNS), Pisa, Italy
- European Brain Research Institute, Rome, Italy
| | - Annalisa Pastore
- Department of Clinical and Basic Neuroscience, Maurice Wohl Institute, King's College London, London, United Kingdom
- Dementia Research Institute, King’s College London, London, United Kingdom
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15
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Tawfik DS, Gruic-Sovulj I. How evolution shapes enzyme selectivity - lessons from aminoacyl-tRNA synthetases and other amino acid utilizing enzymes. FEBS J 2020; 287:1284-1305. [PMID: 31891445 DOI: 10.1111/febs.15199] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/08/2019] [Accepted: 12/30/2019] [Indexed: 12/21/2022]
Abstract
Aminoacyl-tRNA synthetases (AARSs) charge tRNA with their cognate amino acids. Many other enzymes use amino acids as substrates, yet discrimination against noncognate amino acids that threaten the accuracy of protein translation is a hallmark of AARSs. Comparing AARSs to these other enzymes allowed us to recognize patterns in molecular recognition and strategies used by evolution for exercising selectivity. Overall, AARSs are 2-3 orders of magnitude more selective than most other amino acid utilizing enzymes. AARSs also reveal the physicochemical limits of molecular discrimination. For example, amino acids smaller by a single methyl moiety present a discrimination ceiling of ~200, while larger ones can be discriminated by up to 105 -fold. In contrast, substrates larger by a hydroxyl group challenge AARS selectivity, due to promiscuous H-bonding with polar active site groups. This 'hydroxyl paradox' is resolved by editing. Indeed, when the physicochemical discrimination limits are reached, post-transfer editing - hydrolysis of tRNAs charged with noncognate amino acids, evolved. The editing site often selectively recognizes the edited noncognate substrate using the very same feature that the synthetic site could not efficiently discriminate against. Finally, the comparison to other enzymes also reveals that the selectivity of AARSs is an explicitly evolved trait, showing some clear examples of how selection acted not only to optimize catalytic efficiency with the target substrate, but also to abolish activity with noncognate threat substrates ('negative selection').
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Affiliation(s)
- Dan S Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Ita Gruic-Sovulj
- Department of Chemistry, Faculty of Science, University of Zagreb, Croatia
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16
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Kleppe AS, Bornberg-Bauer E. Robustness by intrinsically disordered C-termini and translational readthrough. Nucleic Acids Res 2019; 46:10184-10194. [PMID: 30247639 PMCID: PMC6365619 DOI: 10.1093/nar/gky778] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/20/2018] [Indexed: 12/20/2022] Open
Abstract
During protein synthesis genetic instructions are passed from DNA via mRNA to the ribosome to assemble a protein chain. Occasionally, stop codons in the mRNA are bypassed and translation continues into the untranslated region (3′-UTR). This process, called translational readthrough (TR), yields a protein chain that becomes longer than would be predicted from the DNA sequence alone. Protein sequences vary in propensity for translational errors, which may yield evolutionary constraints by limiting evolutionary paths. Here we investigated TR in Saccharomyces cerevisiae by analysing ribosome profiling data. We clustered proteins as either prone or non-prone to TR, and conducted comparative analyses. We find that a relatively high frequency (5%) of genes undergo TR, including ribosomal subunit proteins. Our main finding is that proteins undergoing TR are highly expressed and have a higher proportion of intrinsically disordered C-termini. We suggest that highly expressed proteins may compensate for the deleterious effects of TR by having intrinsically disordered C-termini, which may provide conformational flexibility but without distorting native function. Moreover, we discuss whether minimizing deleterious effects of TR is also enabling exploration of the phenotypic landscape of protein isoforms.
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Affiliation(s)
- April Snofrid Kleppe
- Institute of Biodiversity and Evolution, University of Münster, Hüfferstr. 1, 48151 Münster, Germany
| | - Erich Bornberg-Bauer
- Institute of Biodiversity and Evolution, University of Münster, Hüfferstr. 1, 48151 Münster, Germany
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17
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Abstract
Evolvability is the ability of a biological system to produce phenotypic variation that is both heritable and adaptive. It has long been the subject of anecdotal observations and theoretical work. In recent years, however, the molecular causes of evolvability have been an increasing focus of experimental work. Here, we review recent experimental progress in areas as different as the evolution of drug resistance in cancer cells and the rewiring of transcriptional regulation circuits in vertebrates. This research reveals the importance of three major themes: multiple genetic and non-genetic mechanisms to generate phenotypic diversity, robustness in genetic systems, and adaptive landscape topography. We also discuss the mounting evidence that evolvability can evolve and the question of whether it evolves adaptively.
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18
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Durante MK, Baums IB, Williams DE, Vohsen S, Kemp DW. What drives phenotypic divergence among coral clonemates of Acropora palmata? Mol Ecol 2019; 28:3208-3224. [PMID: 31282031 PMCID: PMC6852117 DOI: 10.1111/mec.15140] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/10/2019] [Accepted: 05/13/2019] [Indexed: 12/16/2022]
Abstract
Evolutionary rescue of populations depends on their ability to produce phenotypic variation that is heritable and adaptive. DNA mutations are the best understood mechanisms to create phenotypic variation, but other, less well-studied mechanisms exist. Marine benthic foundation species provide opportunities to study these mechanisms because many are dominated by isogenic stands produced through asexual reproduction. For example, Caribbean acroporid corals are long lived and reproduce asexually via breakage of branches. Fragmentation is often the dominant mode of local population maintenance. Thus, large genets with many ramets (colonies) are common. Here, we observed phenotypic variation in stress responses within genets following the coral bleaching events in 2014 and 2015 caused by high water temperatures. This was not due to genetic variation in their symbiotic dinoflagellates (Symbiodinium "fitti") because each genet of this coral species typically harbours a single strain of S. "fitti". Characterization of the microbiome via 16S tag sequencing correlated the abundance of only two microbiome members (Tepidiphilus, Endozoicomonas) with a bleaching response. Epigenetic changes were significantly correlated with the host's genetic background, the location of the sampled polyps within the colonies (e.g., branch vs. base of colony), and differences in the colonies' condition during the bleaching event. We conclude that long-term microenvironmental differences led to changes in the way the ramets methylated their genomes, contributing to the differential bleaching response. However, most of the variation in differential bleaching response among clonemates of Acropora palmata remains unexplained. This research provides novel data and hypotheses to help understand intragenet variability in stress phenotypes of sessile marine species.
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Affiliation(s)
| | | | - Dana E. Williams
- National Oceanic and Atmospheric AdministrationSoutheast Fisheries Science CenterMiamiFLUSA
| | - Sam Vohsen
- The Pennsylvania State UniversityUniversity ParkPAUSA
| | - Dustin W. Kemp
- The Pennsylvania State UniversityUniversity ParkPAUSA
- Present address:
University of Alabama at BirminghamBirminghamALUSA
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19
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Giri S, Waschina S, Kaleta C, Kost C. Defining Division of Labor in Microbial Communities. J Mol Biol 2019; 431:4712-4731. [PMID: 31260694 DOI: 10.1016/j.jmb.2019.06.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 06/13/2019] [Accepted: 06/19/2019] [Indexed: 11/15/2022]
Abstract
In order to survive and reproduce, organisms must perform a multitude of tasks. However, trade-offs limit their ability to allocate energy and resources to all of these different processes. One strategy to solve this problem is to specialize in some traits and team up with other organisms that can help by providing additional, complementary functions. By reciprocally exchanging metabolites and/or services in this way, both parties benefit from the interaction. This phenomenon, which has been termed functional specialization or division of labor, is very common in nature and exists on all levels of biological organization. Also, microorganisms have evolved different types of synergistic interactions. However, very often, it remains unclear whether or not a given example represents a true case of division of labor. Here we aim at filling this gap by providing a list of criteria that clearly define division of labor in microbial communities. Furthermore, we propose a set of diagnostic experiments to verify whether a given interaction fulfills these conditions. In contrast to the common use of the term, our analysis reveals that both intraspecific and interspecific interactions meet the criteria defining division of labor. Moreover, our analysis identified non-cooperators of intraspecific public goods interactions as growth specialists that divide labor with conspecific producers, rather than being social parasites. By providing a conceptual toolkit, our work will help to unambiguously identify cases of division of labor and stimulate more detailed investigations of this important and widespread type of inter-microbial interaction.
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Affiliation(s)
- Samir Giri
- Department of Ecology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | - Silvio Waschina
- Research Group Medical Systems Biology, Institute for Experimental Medicine, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Christoph Kaleta
- Research Group Medical Systems Biology, Institute for Experimental Medicine, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Christian Kost
- Department of Ecology, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany.
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20
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Beaulieu JM, O’Meara BC, Zaretzki R, Landerer C, Chai J, Gilchrist MA. Population Genetics Based Phylogenetics Under Stabilizing Selection for an Optimal Amino Acid Sequence: A Nested Modeling Approach. Mol Biol Evol 2019; 36:834-851. [PMID: 30521036 PMCID: PMC6445302 DOI: 10.1093/molbev/msy222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We present a new phylogenetic approach, selection on amino acids and codons (SelAC), whose substitution rates are based on a nested model linking protein expression to population genetics. Unlike simpler codon models that assume a single substitution matrix for all sites, our model more realistically represents the evolution of protein-coding DNA under the assumption of consistent, stabilizing selection using a cost-benefit approach. This cost-benefit approach allows us to generate a set of 20 optimal amino acid-specific matrix families using just a handful of parameters and naturally links the strength of stabilizing selection to protein synthesis levels, which we can estimate. Using a yeast data set of 100 orthologs for 6 taxa, we find SelAC fits the data much better than popular models by 104-105 Akike information criterion units adjusted for small sample bias. Our results also indicated that nested, mechanistic models better predict observed data patterns highlighting the improvement in biological realism in amino acid sequence evolution that our model provides. Additional parameters estimated by SelAC indicate that a large amount of nonphylogenetic, but biologically meaningful, information can be inferred from existing data. For example, SelAC prediction of gene-specific protein synthesis rates correlates well with both empirical (r=0.33-0.48) and other theoretical predictions (r=0.45-0.64) for multiple yeast species. SelAC also provides estimates of the optimal amino acid at each site. Finally, because SelAC is a nested approach based on clearly stated biological assumptions, future modifications, such as including shifts in the optimal amino acid sequence within or across lineages, are possible.
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Affiliation(s)
- Jeremy M Beaulieu
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN
- National Institute for Mathematical and Biological Synthesis, Knoxville, TN
| | - Brian C O’Meara
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN
- National Institute for Mathematical and Biological Synthesis, Knoxville, TN
| | | | - Cedric Landerer
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN
- National Institute for Mathematical and Biological Synthesis, Knoxville, TN
| | - Juanjuan Chai
- National Institute for Mathematical and Biological Synthesis, Knoxville, TN
- Suite 1039, White Plains, NY
| | - Michael A Gilchrist
- Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN
- National Institute for Mathematical and Biological Synthesis, Knoxville, TN
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21
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Cehovin A, Harrison OB, Lewis SB, Ward PN, Ngetsa C, Graham SM, Sanders EJ, Maiden MCJ, Tang CM. Identification of Novel Neisseria gonorrhoeae Lineages Harboring Resistance Plasmids in Coastal Kenya. J Infect Dis 2018; 218:801-808. [PMID: 29701830 PMCID: PMC6057544 DOI: 10.1093/infdis/jiy240] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/20/2018] [Indexed: 11/13/2022] Open
Abstract
Background Africa has the highest incidence of gonorrhea in the world. However, little is known about gonococcal populations in this continent or mechanisms of antimicrobial resistance (AMR). Methods Whole-genome sequence data were analyzed from 103 Neisseria gonorrhoeae isolates from 73 patients, mainly men who have sex with men, from coastal Kenya. We annotated loci, defined the core genome, defined mechanisms of AMR, and performed phylogenetic analysis. For patients with multiple episodes of gonorrhea, we determined whether infections occurred with related strains. Results We identified 3 clusters of isolates that are phylogenetically distinct from isolates found elsewhere. Plasmids were virtually ubiquitous: pTetM and pblaTEM were found in 97%, and 55% of isolates, respectively. This was associated with high doxycycline use for undiagnosed sexually transmitted infections. Twenty-three percent of multiple episodes of gonorrhea in the same individual were caused by a related strain, suggesting inadequate treatment or reinfection. Conclusions The prevalence of plasmid-mediated AMR in Kenyan gonococci contrasts with that in wealthy countries, where AMR is largely chromosomally mediated. Antimicrobials have a profound effect on the maintenance of lineages harboring plasmids. Doxycycline can select for tetracycline and penicillin resistance, through plasmid cooperation. Understanding the mechanisms of AMR in high-risk groups is required to inform treatment strategies.
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Affiliation(s)
- Ana Cehovin
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom
| | | | - Steven B Lewis
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom
| | - Philip N Ward
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom
| | - Caroline Ngetsa
- Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi, Kenya
| | - Susan M Graham
- Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi, Kenya
- University of Washington, Seattle
| | - Eduard J Sanders
- Nuffield Department of Medicine, University of Oxford, United Kingdom
- Kenya Medical Research Institute–Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Global Health, University of Amsterdam, The Netherlands
| | | | - Christoph M Tang
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom
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22
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Errors during Gene Expression: Single-Cell Heterogeneity, Stress Resistance, and Microbe-Host Interactions. mBio 2018; 9:mBio.01018-18. [PMID: 29970467 PMCID: PMC6030554 DOI: 10.1128/mbio.01018-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Gene expression has been considered a highly accurate process, and deviation from such fidelity has been shown previously to be detrimental for the cell. More recently, increasing evidence has supported the notion that the accuracy of gene expression is indeed flexibly variable. The levels of errors during gene expression differ from condition to condition and even from cell to cell within genetically identical populations grown under the same conditions. The different levels of errors resulting from inaccurate gene expression are now known to play key roles in regulating microbial stress responses and host interactions. This minireview summarizes the recent development in understanding the level, regulation, and physiological impact of errors during gene expression. Gene expression has been considered a highly accurate process, and deviation from such fidelity has been shown previously to be detrimental for the cell. More recently, increasing evidence has supported the notion that the accuracy of gene expression is indeed flexibly variable.
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23
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Petrović D, Risso VA, Kamerlin SCL, Sanchez-Ruiz JM. Conformational dynamics and enzyme evolution. J R Soc Interface 2018; 15:20180330. [PMID: 30021929 PMCID: PMC6073641 DOI: 10.1098/rsif.2018.0330] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 06/27/2018] [Indexed: 12/21/2022] Open
Abstract
Enzymes are dynamic entities, and their dynamic properties are clearly linked to their biological function. It follows that dynamics ought to play an essential role in enzyme evolution. Indeed, a link between conformational diversity and the emergence of new enzyme functionalities has been recognized for many years. However, it is only recently that state-of-the-art computational and experimental approaches are revealing the crucial molecular details of this link. Specifically, evolutionary trajectories leading to functional optimization for a given host environment or to the emergence of a new function typically involve enriching catalytically competent conformations and/or the freezing out of non-competent conformations of an enzyme. In some cases, these evolutionary changes are achieved through distant mutations that shift the protein ensemble towards productive conformations. Multifunctional intermediates in evolutionary trajectories are probably multi-conformational, i.e. able to switch between different overall conformations, each competent for a given function. Conformational diversity can assist the emergence of a completely new active site through a single mutation by facilitating transition-state binding. We propose that this mechanism may have played a role in the emergence of enzymes at the primordial, progenote stage, where it was plausibly promoted by high environmental temperatures and the possibility of additional phenotypic mutations.
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Affiliation(s)
- Dušan Petrović
- Department of Chemistry, BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Valeria A Risso
- Departamento de Quimica Fisica, Facultad de Ciencias, University of Granada, 18071 Granada, Spain
| | | | - Jose M Sanchez-Ruiz
- Departamento de Quimica Fisica, Facultad de Ciencias, University of Granada, 18071 Granada, Spain
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24
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Characterization of a thermostable mutant of Agaricus brasiliensis laccase created by phylogeny-based design. J Biosci Bioeng 2017; 124:623-629. [DOI: 10.1016/j.jbiosc.2017.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/28/2017] [Accepted: 07/07/2017] [Indexed: 12/14/2022]
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25
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Akanuma S. Characterization of Reconstructed Ancestral Proteins Suggests a Change in Temperature of the Ancient Biosphere. Life (Basel) 2017; 7:life7030033. [PMID: 28783077 PMCID: PMC5617958 DOI: 10.3390/life7030033] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 01/02/2023] Open
Abstract
Understanding the evolution of ancestral life, and especially the ability of some organisms to flourish in the variable environments experienced in Earth’s early biosphere, requires knowledge of the characteristics and the environment of these ancestral organisms. Information about early life and environmental conditions has been obtained from fossil records and geological surveys. Recent advances in phylogenetic analysis, and an increasing number of protein sequences available in public databases, have made it possible to infer ancestral protein sequences possessed by ancient organisms. However, the in silico studies that assess the ancestral base content of ribosomal RNAs, the frequency of each amino acid in ancestral proteins, and estimate the environmental temperatures of ancient organisms, show conflicting results. The characterization of ancestral proteins reconstructed in vitro suggests that ancient organisms had very thermally stable proteins, and therefore were thermophilic or hyperthermophilic. Experimental data supports the idea that only thermophilic ancestors survived the catastrophic increase in temperature of the biosphere that was likely associated with meteorite impacts during the early history of Earth. In addition, by expanding the timescale and including more ancestral proteins for reconstruction, it appears as though the Earth’s surface temperature gradually decreased over time, from Archean to present.
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Affiliation(s)
- Satoshi Akanuma
- Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan.
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26
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Yoshida M, Reyes SG, Tsuda S, Horinouchi T, Furusawa C, Cronin L. Time-programmable drug dosing allows the manipulation, suppression and reversal of antibiotic drug resistance in vitro. Nat Commun 2017; 8:15589. [PMID: 28593940 PMCID: PMC5472167 DOI: 10.1038/ncomms15589] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 04/11/2017] [Indexed: 12/30/2022] Open
Abstract
Multi-drug strategies have been attempted to prolong the efficacy of existing antibiotics, but with limited success. Here we show that the evolution of multi-drug-resistant Escherichia coli can be manipulated in vitro by administering pairs of antibiotics and switching between them in ON/OFF manner. Using a multiplexed cell culture system, we find that switching between certain combinations of antibiotics completely suppresses the development of resistance to one of the antibiotics. Using this data, we develop a simple deterministic model, which allows us to predict the fate of multi-drug evolution in this system. Furthermore, we are able to reverse established drug resistance based on the model prediction by modulating antibiotic selection stresses. Our results support the idea that the development of antibiotic resistance may be potentially controlled via continuous switching of drugs.
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Affiliation(s)
- Mari Yoshida
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK
| | | | - Soichiro Tsuda
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK
| | - Takaaki Horinouchi
- Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
| | - Chikara Furusawa
- Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan
- Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Leroy Cronin
- WestCHEM, School of Chemistry, The University of Glasgow, Glasgow G12 8QQ, UK
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27
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Lind PA, Arvidsson L, Berg OG, Andersson DI. Variation in Mutational Robustness between Different Proteins and the Predictability of Fitness Effects. Mol Biol Evol 2017; 34:408-418. [PMID: 28025272 DOI: 10.1093/molbev/msw239] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Random mutations in genes from disparate protein classes may have different distributions of fitness effects (DFEs) depending on different structural, functional, and evolutionary constraints. We measured the fitness effects of 156 single mutations in the genes encoding AraC (transcription factor), AraD (enzyme), and AraE (transporter) used for bacterial growth on l-arabinose. Despite their different molecular functions these genes all had bimodal DFEs with most mutations either being neutral or strongly deleterious, providing a general expectation for the DFE. This contrasts with the unimodal DFEs previously obtained for ribosomal protein genes where most mutations were slightly deleterious. Based on theoretical considerations, we suggest that the 33-fold higher average mutational robustness of ribosomal proteins is due to stronger selection for reduced costs of translational and transcriptional errors. Whereas the large majority of synonymous mutations were deleterious for ribosomal proteins genes, no fitness effects could be detected for the AraCDE genes. Four mutations in AraC and AraE increased fitness, suggesting that slightly advantageous mutations make up a significant fraction of the DFE, but that they often escape detection due to the limited sensitivity of commonly used fitness assays. We show that the fitness effects of amino acid substitutions can be predicted based on evolutionary conservation, but those weakly deleterious mutations are less reliably detected. This suggests that large-effect mutations and the fraction of highly deleterious mutations can be computationally predicted, but that experiments are required to characterize the DFE close to neutrality, where many mutations ultimately fixed in a population will occur.
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Affiliation(s)
- Peter A Lind
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.,Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Lars Arvidsson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Otto G Berg
- Department of Cell and Molecular Biology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
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28
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Pharmacodynamics of Ceftolozane Combined with Tazobactam against Enterobacteriaceae in a Neutropenic Mouse Thigh Model. Antimicrob Agents Chemother 2016; 60:7272-7279. [PMID: 27671063 DOI: 10.1128/aac.01580-16] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/17/2016] [Indexed: 01/20/2023] Open
Abstract
Ceftolozane is a new broad-spectrum cephalosporin and is combined with tazobactam to broaden the activity of ceftolozane against strains producing extended-spectrum beta-lactamases (ESBLs). We determined the pharmacodynamics (PD) of the combination in the neutropenic mouse thigh model to determine the optimal exposure of tazobactam. Treatment of CD-1 neutropenic mice was started 2 h after infection with ceftolozane every 2 h (q2h) alone or in combination with tazobactam at different dosing frequencies for 24 h, and the number of CFU in the thighs was determined before and after treatment. The maximum effect model was fit to the dose-response and the pharmacokinetic/PD index (PDI)-response to determine the PDI values for ceftolozane alone and ceftolozane in combination with tazobactam resulting in a static effect and a 1-log kill. The effect of tazobactam was dependent on the percentage of time that the free drug concentration remained above the concentration threshold (percent [Formula: see text]), whereby dosing q2h was more efficacious than dosing every 8 h (q8h), reducing the tazobactam daily dose by a factor 6.9 to 59.0 (n = 3 strains) to obtain a static effect. Using R2 as an indicator of the best fit of the percent [Formula: see text]-response relationships, the concentration threshold best correlating with the response varied from 0.5 to 2 mg/liter, depending on the strain. A similar result was obtained when the q2h and q8h regimens were analyzed. For all isolates tested, the mean [Formula: see text] for 0.5 mg/liter tazobactam was 28.2% (range, 17.5 to 45.8%) and 44.4% (range, 26.6 to 54.7%) for a static effect and a 1-log kill, respectively, at ceftolozane exposures that produced a ceftolozane concentration of 4 mg/liter (a concentration greater than the MIC) for 33.9 to 63.3% of a 24-h period under steady-state pharmacokinetic conditions. The main PDI that correlated with the effect of tazobactam was the [Formula: see text] achieved with a CT of 0.5 mg/liter tazobactam.
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29
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Trudeau DL, Kaltenbach M, Tawfik DS. On the Potential Origins of the High Stability of Reconstructed Ancestral Proteins. Mol Biol Evol 2016; 33:2633-41. [PMID: 27413048 DOI: 10.1093/molbev/msw138] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ancestral reconstruction provides instrumental insights regarding the biochemical and biophysical characteristics of past proteins. A striking observation relates to the remarkably high thermostability of reconstructed ancestors. The latter has been linked to high environmental temperatures in the Precambrian era, the era relating to most reconstructed proteins. We found that inferred ancestors of the serum paraoxonase (PON) enzyme family, including the mammalian ancestor, exhibit dramatically increased thermostabilities compared with the extant, human enzyme (up to 30 °C higher melting temperature). However, the environmental temperature at the time of emergence of mammals is presumed to be similar to the present one. Additionally, the mammalian PON ancestor has superior folding properties (kinetic stability)-unlike the extant mammalian PONs, it expresses in E. coli in a soluble and functional form, and at a high yield. We discuss two potential origins of this unexpectedly high stability. First, ancestral stability may be overestimated by a "consensus effect," whereby replacing amino acids that are rare in contemporary sequences with the amino acid most common in the family increases protein stability. Comparison to other reconstructed ancestors indicates that the consensus effect may bias some but not all reconstructions. Second, we note that high stability may relate to factors other than high environmental temperature such as oxidative stress or high radiation levels. Foremost, intrinsic factors such as high rates of genetic mutations and/or of transcriptional and translational errors, and less efficient protein quality control systems, may underlie the high kinetic and thermodynamic stability of past proteins.
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Affiliation(s)
- Devin L Trudeau
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Miriam Kaltenbach
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Dan S Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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Steinberg B, Ostermeier M. Shifting Fitness and Epistatic Landscapes Reflect Trade-offs along an Evolutionary Pathway. J Mol Biol 2016; 428:2730-43. [DOI: 10.1016/j.jmb.2016.04.033] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/18/2016] [Accepted: 04/29/2016] [Indexed: 01/04/2023]
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Abstract
How biological systems such as proteins achieve robustness to ubiquitous perturbations is a fundamental biological question. Such perturbations include errors that introduce phenotypic mutations into nascent proteins during the translation of mRNA. These errors are remarkably frequent. They are also costly, because they reduce protein stability and help create toxic misfolded proteins. Adaptive evolution might reduce these costs of protein mistranslation by two principal mechanisms. The first increases the accuracy of translation via synonymous "high fidelity" codons at especially sensitive sites. The second increases the robustness of proteins to phenotypic errors via amino acids that increase protein stability. To study how these mechanisms are exploited by populations evolving in the laboratory, we evolved the antibiotic resistance gene TEM-1 in Escherichia coli hosts with either normal or high rates of mistranslation. We analyzed TEM-1 populations that evolved under relaxed and stringent selection for antibiotic resistance by single molecule real-time sequencing. Under relaxed selection, mistranslating populations reduce mistranslation costs by reducing TEM-1 expression. Under stringent selection, they efficiently purge destabilizing amino acid changes. More importantly, they accumulate stabilizing amino acid changes rather than synonymous changes that increase translational accuracy. In the large populations we study, and on short evolutionary timescales, the path of least resistance in TEM-1 evolution consists of reducing the consequences of translation errors rather than the errors themselves.
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Meyer AJ, Garry DJ, Hall B, Byrom MM, McDonald HG, Yang X, Yin YW, Ellington AD. Transcription yield of fully 2'-modified RNA can be increased by the addition of thermostabilizing mutations to T7 RNA polymerase mutants. Nucleic Acids Res 2015. [PMID: 26209133 PMCID: PMC4551944 DOI: 10.1093/nar/gkv734] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
On average, mutations are deleterious to proteins. Mutations conferring new function to a protein often come at the expense of protein folding or stability, reducing overall activity. Over the years, a panel of T7 RNA polymerases have been designed or evolved to accept nucleotides with modified ribose moieties. These modified RNAs have proven useful, especially in vivo, but the transcriptional yields tend to be quite low. Here we show that mutations previously shown to increase the thermal tolerance of T7 RNA polymerase can increase the activity of mutants with expanded substrate range. The resulting polymerase mutants can be used to generate 2'-O-methyl modified RNA with yields much higher than enzymes currently employed.
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Affiliation(s)
- Adam J Meyer
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Daniel J Garry
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Bradley Hall
- Altermune Technologies, LLC, Irvine, CA 92606, USA
| | - Michelle M Byrom
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Hannah G McDonald
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Xu Yang
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Y Whitney Yin
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Andrew D Ellington
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA Center for Systems & Synthetic Biology, University of Texas at Austin, Austin, TX 78712, USA
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Vallazza B, Petri S, Poleganov MA, Eberle F, Kuhn AN, Sahin U. Recombinant messenger RNA technology and its application in cancer immunotherapy, transcript replacement therapies, pluripotent stem cell induction, and beyond. WILEY INTERDISCIPLINARY REVIEWS-RNA 2015; 6:471-99. [DOI: 10.1002/wrna.1288] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/23/2015] [Accepted: 04/28/2015] [Indexed: 12/24/2022]
Affiliation(s)
| | | | | | | | | | - Ugur Sahin
- BioNTech RNA Pharmaceuticals GmbH; Mainz Germany
- TRON gGmbH; Mainz Germany
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35
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Fares MA. The origins of mutational robustness. Trends Genet 2015; 31:373-81. [PMID: 26013677 DOI: 10.1016/j.tig.2015.04.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/27/2015] [Accepted: 04/28/2015] [Indexed: 11/17/2022]
Abstract
Biological systems are resistant to genetic changes; a property known as mutational robustness, the origin of which remains an open question. In recent years, researchers have explored emergent properties of biological systems and mechanisms of genetic redundancy to reveal how mutational robustness emerges and persists. Several mechanisms have been proposed to explain the origin of mutational robustness, including molecular chaperones and gene duplication. The latter has received much attention, but its role in robustness remains controversial. Here, I examine recent findings linking genetic redundancy through gene duplication and mutational robustness. Experimental evolution and genome resequencing have made it possible to test the role of gene duplication in tolerating mutations at both the coding and regulatory levels. This evidence as well as previous findings on regulatory reprogramming of duplicates support the role of gene duplication in the origin of robustness.
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Affiliation(s)
- Mario A Fares
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Valencia, Spain; Department of Genetics, Smurfit Institute of Genetics, University of Dublin, Trinity College Dublin, Dublin, Ireland.
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Imashimizu M, Takahashi H, Oshima T, McIntosh C, Bubunenko M, Court DL, Kashlev M. Visualizing translocation dynamics and nascent transcript errors in paused RNA polymerases in vivo. Genome Biol 2015; 16:98. [PMID: 25976475 PMCID: PMC4457086 DOI: 10.1186/s13059-015-0666-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 05/05/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Transcription elongation is frequently interrupted by pausing signals in DNA, with downstream effects on gene expression. Transcription errors also induce prolonged pausing, which can lead to a destabilized genome by interfering with DNA replication. Mechanisms of pausing associated with translocation blocks and misincorporation have been characterized in vitro, but not in vivo. RESULTS We investigate the pausing pattern of RNA polymerase (RNAP) in Escherichia coli by a novel approach, combining native elongating transcript sequencing (NET-seq) with RNase footprinting of the transcripts (RNET-seq). We reveal that the G-dC base pair at the 5' end of the RNA-DNA hybrid interferes with RNAP translocation. The distance between the 5' G-dC base pair and the 3' end of RNA fluctuates over a three-nucleotide width. Thus, the G-dC base pair can induce pausing in post-translocated, pre-translocated, and backtracked states of RNAP. Additionally, a CpG sequence of the template DNA strand spanning the active site of RNAP inhibits elongation and induces G-to-A errors, which leads to backtracking of RNAP. Gre factors efficiently proofread the errors and rescue the backtracked complexes. We also find that pausing events are enriched in the 5' untranslated region and antisense transcription of mRNA genes and are reduced in rRNA genes. CONCLUSIONS In E. coli, robust transcriptional pausing involves RNAP interaction with G-dC at the upstream end of the RNA-DNA hybrid, which interferes with translocation. CpG DNA sequences induce transcriptional pausing and G-to-A errors.
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Affiliation(s)
- Masahiko Imashimizu
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8673, Japan.
| | - Taku Oshima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Ikoma, Nara, 630-0192, Japan.
| | - Carl McIntosh
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Mikhail Bubunenko
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Donald L Court
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
| | - Mikhail Kashlev
- Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA.
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Wons E, Furmanek-Blaszk B, Sektas M. RNA editing by T7 RNA polymerase bypasses InDel mutations causing unexpected phenotypic changes. Nucleic Acids Res 2015; 43:3950-63. [PMID: 25824942 PMCID: PMC4417176 DOI: 10.1093/nar/gkv269] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 12/26/2022] Open
Abstract
DNA-dependent T7 RNA polymerase (T7 RNAP) is the most powerful tool for both gene expression and in vitro transcription. By using a Next Generation Sequencing (NGS) approach we have analyzed the polymorphism of a T7 RNAP-generated mRNA pool of the mboIIM2 gene. We find that the enzyme displays a relatively high level of template-dependent transcriptional infidelity. The nucleotide misincorporations and multiple insertions in A/T-rich tracts of homopolymers in mRNA (0.20 and 0.089%, respectively) cause epigenetic effects with significant impact on gene expression that is disproportionally high to their frequency of appearance. The sequence-dependent rescue of single and even double InDel frameshifting mutants and wild-type phenotype recovery is observed as a result. As a consequence, a heterogeneous pool of functional and non-functional proteins of almost the same molecular mass is produced where the proteins are indistinguishable from each other upon ordinary analysis. We suggest that transcriptional infidelity as a general feature of the most effective RNAPs may serve to repair and/or modify a protein function, thus increasing the repertoire of phenotypic variants, which in turn has a high evolutionary potential.
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Affiliation(s)
- Ewa Wons
- Department of Microbiology, University of Gdansk, Gdansk 80-308, Poland
| | | | - Marian Sektas
- Department of Microbiology, University of Gdansk, Gdansk 80-308, Poland
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38
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Gordon AJE, Satory D, Halliday JA, Herman C. Lost in transcription: transient errors in information transfer. Curr Opin Microbiol 2015; 24:80-7. [PMID: 25637723 DOI: 10.1016/j.mib.2015.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/29/2014] [Accepted: 01/10/2015] [Indexed: 10/24/2022]
Abstract
Errors in information transfer from DNA to RNA to protein are inevitable. Here, we focus on errors that occur in nascent transcripts during transcription, epimutations. Recent approaches using novel cDNA library preparation and next-generation sequencing begin to directly determine the rate of epimutation and allow analysis of the epimutational spectrum of transcription errors, the type and sequence context of the errors produced in a transcript by an RNA polymerase. The phenotypic consequences of transcription errors have been assessed using both forward and reverse epimutation systems. These studies reveal that transient transcription errors can produce a modification of cell phenotype, partial phenotypic suppression of a mutant allele, and a heritable change in cell phenotype, epigenetic switching in a bistable gene network.
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Affiliation(s)
- Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Dominik Satory
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jennifer A Halliday
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA.
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39
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Ferenci T, Maharjan R. Mutational heterogeneity: A key ingredient of bet-hedging and evolutionary divergence? Bioessays 2014; 37:123-30. [DOI: 10.1002/bies.201400153] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Thomas Ferenci
- School of Molecular Bioscience; University of Sydney; NSW Australia
| | - Ram Maharjan
- School of Molecular Bioscience; University of Sydney; NSW Australia
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40
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Siegal ML, Leu JY. On the Nature and Evolutionary Impact of Phenotypic Robustness Mechanisms. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2014; 45:496-517. [PMID: 26034410 PMCID: PMC4448758 DOI: 10.1146/annurev-ecolsys-120213-091705] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Biologists have long observed that physiological and developmental processes are insensitive, or robust, to many genetic and environmental perturbations. A complete understanding of the evolutionary causes and consequences of this robustness is lacking. Recent progress has been made in uncovering the regulatory mechanisms that underlie environmental robustness in particular. Less is known about robustness to the effects of mutations, and indeed the evolution of mutational robustness remains a controversial topic. The controversy has spread to related topics, in particular the evolutionary relevance of cryptic genetic variation. This review aims to synthesize current understanding of robustness mechanisms and to cut through the controversy by shedding light on what is and is not known about mutational robustness. Some studies have confused mutational robustness with non-additive interactions between mutations (epistasis). We conclude that a profitable way forward is to focus investigations (and rhetoric) less on mutational robustness and more on epistasis.
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Affiliation(s)
- Mark L Siegal
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, New York 10003;
| | - Jun-Yi Leu
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan 11529;
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41
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Tawfik DS. Accuracy-rate tradeoffs: how do enzymes meet demands of selectivity and catalytic efficiency? Curr Opin Chem Biol 2014; 21:73-80. [DOI: 10.1016/j.cbpa.2014.05.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 05/10/2014] [Indexed: 12/11/2022]
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42
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Ellefson JW, Meyer AJ, Hughes RA, Cannon JR, Brodbelt JS, Ellington AD. Directed evolution of genetic parts and circuits by compartmentalized partnered replication. Nat Biotechnol 2013; 32:97-101. [DOI: 10.1038/nbt.2714] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/05/2013] [Indexed: 11/09/2022]
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43
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Rockah-Shmuel L, Tóth-Petróczy Á, Sela A, Wurtzel O, Sorek R, Tawfik DS. Correlated occurrence and bypass of frame-shifting insertion-deletions (InDels) to give functional proteins. PLoS Genet 2013; 9:e1003882. [PMID: 24204297 PMCID: PMC3812077 DOI: 10.1371/journal.pgen.1003882] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 09/02/2013] [Indexed: 11/19/2022] Open
Abstract
Short insertions and deletions (InDels) comprise an important part of the natural mutational repertoire. InDels are, however, highly deleterious, primarily because two-thirds result in frame-shifts. Bypass through slippage over homonucleotide repeats by transcriptional and/or translational infidelity is known to occur sporadically. However, the overall frequency of bypass and its relation to sequence composition remain unclear. Intriguingly, the occurrence of InDels and the bypass of frame-shifts are mechanistically related - occurring through slippage over repeats by DNA or RNA polymerases, or by the ribosome, respectively. Here, we show that the frequency of frame-shifting InDels, and the frequency by which they are bypassed to give full-length, functional proteins, are indeed highly correlated. Using a laboratory genetic drift, we have exhaustively mapped all InDels that occurred within a single gene. We thus compared the naive InDel repertoire that results from DNA polymerase slippage to the frame-shifting InDels tolerated following selection to maintain protein function. We found that InDels repeatedly occurred, and were bypassed, within homonucleotide repeats of 3–8 bases. The longer the repeat, the higher was the frequency of InDels formation, and the more frequent was their bypass. Besides an expected 8A repeat, other types of repeats, including short ones, and G and C repeats, were bypassed. Although obtained in vitro, our results indicate a direct link between the genetic occurrence of InDels and their phenotypic rescue, thus suggesting a potential role for frame-shifting InDels as bridging evolutionary intermediates. Homonucleotide repeats are exceptionally prone to insertions and/or deletions of bases (InDels). However, unless they occur in a multiplicity of 3 bases, InDels disrupt the reading frame and are thus expected to be purged from coding regions. Homonucleotide repeats, however, are also vulnerable to slippage by RNA polymerases and the ribosome. Using laboratory evolution techniques, we systematically mapped the occurrence of InDels within a given gene, before and after selection. Our data indicate that frame-shifting InDels were frequently bypassed to give functional proteins at surprisingly high frequencies. Further, we found a strict correlation between the repeat length, the frequency of occurrence of InDels at the DNA level, and the likelihood of bypass by transcriptional/translational slippage. Our results suggest that frame-shifting InDels might comprise functional evolutionary intermediates, and an effective mean of sequence divergence (e.g. when an adjacent InDel restores the frame, resulting in altered sequence and, potentially, in an altered protein structure).
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Affiliation(s)
- Liat Rockah-Shmuel
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Ágnes Tóth-Petróczy
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Asaf Sela
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Omri Wurtzel
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Rotem Sorek
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Dan S. Tawfik
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
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44
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Imashimizu M, Oshima T, Lubkowska L, Kashlev M. Direct assessment of transcription fidelity by high-resolution RNA sequencing. Nucleic Acids Res 2013; 41:9090-104. [PMID: 23925128 PMCID: PMC3799451 DOI: 10.1093/nar/gkt698] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cancerous and aging cells have long been thought to be impacted by transcription errors that cause genetic and epigenetic changes. Until now, a lack of methodology for directly assessing such errors hindered evaluation of their impact to the cells. We report a high-resolution Illumina RNA-seq method that can assess noncoded base substitutions in mRNA at 10−4–10−5 per base frequencies in vitro and in vivo. Statistically reliable detection of changes in transcription fidelity through ∼103 nt DNA sites assures that the RNA-seq can analyze the fidelity in a large number of the sites where errors occur. A combination of the RNA-seq and biochemical analyses of the positions for the errors revealed two sequence-specific mechanisms that increase transcription fidelity by Escherichia coli RNA polymerase: (i) enhanced suppression of nucleotide misincorporation that improves selectivity for the cognate substrate, and (ii) increased backtracking of the RNA polymerase that decreases a chance of error propagation to the full-length transcript after misincorporation and provides an opportunity to proofread the error. This method is adoptable to a genome-wide assessment of transcription fidelity.
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Affiliation(s)
- Masahiko Imashimizu
- Gene Regulation and Chromosome Biology Laboratory, Frederick National Laboratory for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA and Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara 630-0192, Japan
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45
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Abstract
Theoretical studies have focused on the environmental temperature of the universal common ancestor of life with conflicting conclusions. Here we provide experimental support for the existence of a thermophilic universal common ancestor. We present the thermal stabilities and catalytic efficiencies of nucleoside diphosphate kinases (NDK), designed using the information contained in predictive phylogenetic trees, that seem to represent the last common ancestors of Archaea and of Bacteria. These enzymes display extreme thermal stabilities, suggesting thermophilic ancestries for Archaea and Bacteria. The results are robust to the uncertainties associated with the sequence predictions and to the tree topologies used to infer the ancestral sequences. Moreover, mutagenesis experiments suggest that the universal ancestor also possessed a very thermostable NDK. Because, as we show, the stability of an NDK is directly related to the environmental temperature of its host organism, our results indicate that the last common ancestor of extant life was a thermophile that flourished at a very high temperature.
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46
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Schenk MF, Szendro IG, Krug J, de Visser JAGM. Quantifying the adaptive potential of an antibiotic resistance enzyme. PLoS Genet 2012; 8:e1002783. [PMID: 22761587 PMCID: PMC3386231 DOI: 10.1371/journal.pgen.1002783] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 05/09/2012] [Indexed: 12/30/2022] Open
Abstract
For a quantitative understanding of the process of adaptation, we need to understand its "raw material," that is, the frequency and fitness effects of beneficial mutations. At present, most empirical evidence suggests an exponential distribution of fitness effects of beneficial mutations, as predicted for Gumbel-domain distributions by extreme value theory. Here, we study the distribution of mutation effects on cefotaxime (Ctx) resistance and fitness of 48 unique beneficial mutations in the bacterial enzyme TEM-1 β-lactamase, which were obtained by screening the products of random mutagenesis for increased Ctx resistance. Our contributions are threefold. First, based on the frequency of unique mutations among more than 300 sequenced isolates and correcting for mutation bias, we conservatively estimate that the total number of first-step mutations that increase Ctx resistance in this enzyme is 87 [95% CI 75-189], or 3.4% of all 2,583 possible base-pair substitutions. Of the 48 mutations, 10 are synonymous and the majority of the 38 non-synonymous mutations occur in the pocket surrounding the catalytic site. Second, we estimate the effects of the mutations on Ctx resistance by determining survival at various Ctx concentrations, and we derive their fitness effects by modeling reproduction and survival as a branching process. Third, we find that the distribution of both measures follows a Fréchet-type distribution characterized by a broad tail of a few exceptionally fit mutants. Such distributions have fundamental evolutionary implications, including an increased predictability of evolution, and may provide a partial explanation for recent observations of striking parallel evolution of antibiotic resistance.
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Affiliation(s)
- Martijn F. Schenk
- Institute for Genetics, University of Cologne, Köln, Germany
- Laboratory of Genetics, Wageningen University, Wageningen, The Netherlands
| | - Ivan G. Szendro
- Institute for Theoretical Physics, University of Cologne, Köln, Germany
| | - Joachim Krug
- Institute for Theoretical Physics, University of Cologne, Köln, Germany
- Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Köln, Germany
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47
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Kleinman CL, Majewski J. Comment on "Widespread RNA and DNA sequence differences in the human transcriptome". Science 2012; 335:1302; author reply 1302. [PMID: 22422962 DOI: 10.1126/science.1209658] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Li et al. (Research Articles, 1 July 2011, p. 53; published online 19 May 2011) reported large numbers of differences between DNA and messenger RNA in human cells, indicating unprecedented levels of RNA editing, and including sequence changes not produced by any of the known RNA editing mechanisms. However, common sources of systematic errors in high-throughput sequencing technology, which were not properly accounted for in this study, explain most of the claimed differences.
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Affiliation(s)
- Claudia L Kleinman
- Department of Human Genetics, McGill University, Montreal, Quebec, Canada.
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48
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Level of gene expression is a major determinant of protein evolution in the viral order Mononegavirales. J Virol 2012; 86:5253-63. [PMID: 22345453 DOI: 10.1128/jvi.06050-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Although the rate at which proteins change is a key parameter in molecular evolution, its determinants are poorly understood in viruses. A variety of factors, including gene length, codon usage bias, protein abundance, protein function, and gene expression level, have been shown to affect the rate of protein evolution in a diverse array of organisms. However, the role of these factors in viral evolution has yet to be addressed. The polar 3'-5' stepwise attenuation of transcription in the Mononegavirales, a group of single-strand negative-sense RNA viruses, provides a unique system to explore the determinants of protein evolution in viruses. We analyzed the relative importance of a variety of factors in shaping patterns of sequence variation in full-length genomes from 13 Mononegavirales species. Our analysis suggests that the level of gene expression, and by extension the relative genomic position of each gene, is a key determinant of the protein evolution in these viruses. This appears to be the consequence of selection for translational robustness, but not for translational accuracy, in highly expressed genes. The small genome size and number of proteins encoded by these viruses allowed us to identify other protein-specific factors that may also play a role in virus evolution, such as host-virus interactions and functional constraints. Finally, we explored the evolutionary pressures acting on noncoding regions in Mononegavirales genomes and observed that, despite being less constrained than coding regions, their evolutionary rates are also associated with genomic position.
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Cusack BP, Arndt PF, Duret L, Roest Crollius H. Preventing dangerous nonsense: selection for robustness to transcriptional error in human genes. PLoS Genet 2011; 7:e1002276. [PMID: 22022272 PMCID: PMC3192821 DOI: 10.1371/journal.pgen.1002276] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Accepted: 07/12/2011] [Indexed: 11/19/2022] Open
Abstract
Nonsense Mediated Decay (NMD) degrades transcripts that contain a premature STOP codon resulting from mistranscription or missplicing. However NMD's surveillance of gene expression varies in efficiency both among and within human genes. Previous work has shown that the intron content of human genes is influenced by missplicing events invisible to NMD. Given the high rate of transcriptional errors in eukaryotes, we hypothesized that natural selection has promoted a dual strategy of “prevention and cure” to alleviate the problem of nonsense transcriptional errors. A prediction of this hypothesis is that NMD's inefficiency should leave a signature of “transcriptional robustness” in human gene sequences that reduces the frequency of nonsense transcriptional errors. For human genes we determined the usage of “fragile” codons, prone to mistranscription into STOP codons, relative to the usage of “robust” codons that do not generate nonsense errors. We observe that single-exon genes have evolved to become robust to mistranscription, because they show a significant tendency to avoid fragile codons relative to robust codons when compared to multi-exon genes. A similar depletion is evident in last exons of multi-exon genes. Histone genes are particularly depleted of fragile codons and thus highly robust to transcriptional errors. Finally, the protein products of single-exon genes show a strong tendency to avoid those amino acids that can only be encoded using fragile codons. Each of these observations can be attributed to NMD deficiency. Thus, in the human genome, wherever the “cure” for nonsense (i.e. NMD) is inefficient, there is increased reliance on the strategy of nonsense “prevention” (i.e. transcriptional robustness). This study shows that human genes are exposed to the deleterious influence of transcriptional errors. Moreover, it suggests that gene expression errors are an underestimated phenomenon, in molecular evolution in general and in selection for genomic robustness in particular. In biological systems mistakes are made constantly because the cellular machinery is complex and error-prone. Mistakes are made in copying DNA for transmission to offspring (“genetic mutations”) but are much more frequent in the day-to-day task of gene expression. Genetic mutations are heritable and therefore have long been the almost exclusive focus of evolutionary genetics research. In contrast, gene expression errors are not inherited and have tended to be disregarded in evolutionary studies. Here we show how human genes have evolved a mechanism to reduce the occurrence of a specific type of gene expression error—transcriptional errors that create premature STOP codons (so-called “nonsense errors”). Nonsense errors are potentially highly toxic for the cell, so natural selection has evolved a strategy called Nonsense Mediated Decay (NMD) to “cure” such errors. However this cure is inefficient. Here we describe how a preventative strategy of “transcriptional robustness” has evolved to decrease the frequency of nonsense errors. Moreover, these “prevention and cure” strategies are used interchangeably—the most transcriptionally robust genes are those for which NMD is most inefficient. Our work implies that gene expression errors play an important role as supporting actors to genetic mutations in molecular evolution, particularly in the evolution of robustness.
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Affiliation(s)
- Brian P Cusack
- Max Planck Institute for Molecular Genetics, Department of Computational Molecular Biology, Berlin, Germany.
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