1
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Ruden DM. GC Content in Nuclear-Encoded Genes and Effective Number of Codons (ENC) Are Positively Correlated in AT-Rich Species and Negatively Correlated in GC-Rich Species. Genes (Basel) 2025; 16:432. [PMID: 40282392 PMCID: PMC12026676 DOI: 10.3390/genes16040432] [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: 02/26/2025] [Revised: 03/31/2025] [Accepted: 04/02/2025] [Indexed: 04/29/2025] Open
Abstract
BACKGROUND/OBJECTIVES Codon usage bias affects gene expression and translation efficiency across species. The effective number of codons (ENC) and GC content influence codon preference, often displaying unimodal or bimodal distributions. This study investigates the correlation between ENC and GC rankings across species and how their relationship affects codon usage distributions. METHODS I analyzed nuclear-encoded genes from 17 species representing six kingdoms: one bacteria (Escherichia coli), three fungi (Saccharomyces cerevisiae, Neurospora crassa, and Schizosaccharomyces pombe), one archaea (Methanococcus aeolicus), three protists (Rickettsia hoogstraalii, Dictyostelium discoideum, and Plasmodium falciparum),), three plants (Musa acuminata, Oryza sativa, and Arabidopsis thaliana), and six animals (Anopheles gambiae, Apis mellifera, Polistes canadensis, Mus musculus, Homo sapiens, and Takifugu rubripes). Genes in all 17 species were ranked by GC content and ENC, and correlations were assessed. I examined how adding or subtracting these rankings influenced their overall distribution in a new method that I call Two-Rank Order Normalization or TRON. The equation, TRON = SUM(ABS((GC rank1:GC rankN) - (ENC rank1:ENC rankN))/(N2/3), where (GC rank1:GC rankN) is a rank-order series of GC rank, (ENC rank1:ENC rankN) is a rank-order series ENC rank, sorted by the rank-order series GC rank. The denominator of TRON, N2/3, is the normalization factor because it is the expected value of the sum of the absolute value of GC rank-ENC rank for all genes if GC rank and ENC rank are not correlated. RESULTS ENC and GC rankings are positively correlated (i.e., ENC increases as GC increases) in AT-rich species such as honeybees (R2 = 0.60, slope = 0.78) and wasps (R2 = 0.52, slope = 0.72) and negatively correlated (i.e., ENC decreases as GC increases) in GC-rich species such as humans (R2 = 0.38, slope = -0.61) and rice (R2 = 0.59, slope = -0.77). Second, the GC rank-ENC rank distributions change from unimodal to bimodal as GC content increases in the 17 species. Third, the GC rank+ENC rank distributions change from bimodal to unimodal as GC content increases in the 17 species. Fourth, the slopes of the correlations (GC versus ENC) in all 17 species are negatively correlated with TRON (R2 = 0.98) (see Graphic Abstract). CONCLUSIONS The correlation between ENC rank and GC rank differs among species, shaping codon usage distributions in opposite ways depending on whether a species' nuclear-encoded genes are AT-rich or GC-rich. Understanding these patterns might provide insights into translation efficiency, epigenetics mediated by CpG DNA methylation, epitranscriptomics of RNA modifications, RNA secondary structures, evolutionary pressures, and potential applications in genetic engineering and biotechnology.
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Affiliation(s)
- Douglas M Ruden
- C. S. Mott Center for Human Growth and Development, Institute for Environmental Health Sciences, Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201, USA
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2
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Eldin P, David A, Hirtz C, Battini JL, Briant L. SARS-CoV-2 Displays a Suboptimal Codon Usage Bias for Efficient Translation in Human Cells Diverted by Hijacking the tRNA Epitranscriptome. Int J Mol Sci 2024; 25:11614. [PMID: 39519170 PMCID: PMC11546939 DOI: 10.3390/ijms252111614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2024] [Revised: 10/25/2024] [Accepted: 10/26/2024] [Indexed: 11/16/2024] Open
Abstract
Codon bias analysis of SARS-CoV-2 reveals suboptimal adaptation for translation in human cells it infects. The detailed examination of the codons preferentially used by SARS-CoV-2 shows a strong preference for LysAAA, GlnCAA, GluGAA, and ArgAGA, which are infrequently used in human genes. In the absence of an adapted tRNA pool, efficient decoding of these codons requires a 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2) modification at the U34 wobble position of the corresponding tRNAs (tLysUUU; tGlnUUG; tGluUUC; tArgUCU). The optimal translation of SARS-CoV-2 open reading frames (ORFs) may therefore require several adjustments to the host's translation machinery, enabling the highly biased viral genome to achieve a more favorable "Ready-to-Translate" state in human cells. Experimental approaches based on LC-MS/MS quantification of tRNA modifications and on alteration of enzymatic tRNA modification pathways provide strong evidence to support the hypothesis that SARS-CoV-2 induces U34 tRNA modifications and relies on these modifications for its lifecycle. The conclusions emphasize the need for future studies on the evolution of SARS-CoV-2 codon bias and its ability to alter the host tRNA pool through the manipulation of RNA modifications.
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Affiliation(s)
- Patrick Eldin
- Institut de Recherche en Infectiologie de Montpellier (IRIM), University of Montpellier, CNRS UMR 9004, 1919 route de Mende, 34293 Montpellier, France
| | - Alexandre David
- Institut de Génomique Fonctionnelle (IGF), INSERM U1191, 141 Rue de la Cardonille, 34000 Montpellier, France
- Institute for Regenerative Medicine and Biotherapy (IRMB)-Plateforme de Protéomique Clinique (PPC), Institut des Neurosciences de Montpellier (INM), University of Montpellier, CHU Montpellier, INSERM CNRS, 298 Rue du Truel, 34090 Montpellier, France
| | - Christophe Hirtz
- Institute for Regenerative Medicine and Biotherapy (IRMB)-Plateforme de Protéomique Clinique (PPC), Institut des Neurosciences de Montpellier (INM), University of Montpellier, CHU Montpellier, INSERM CNRS, 298 Rue du Truel, 34090 Montpellier, France
| | - Jean-Luc Battini
- Institut de Recherche en Infectiologie de Montpellier (IRIM), University of Montpellier, CNRS UMR 9004, 1919 route de Mende, 34293 Montpellier, France
| | - Laurence Briant
- Institut de Recherche en Infectiologie de Montpellier (IRIM), University of Montpellier, CNRS UMR 9004, 1919 route de Mende, 34293 Montpellier, France
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3
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Gallardo-Dodd CJ, Kutter C. The regulatory landscape of interacting RNA and protein pools in cellular homeostasis and cancer. Hum Genomics 2024; 18:109. [PMID: 39334294 PMCID: PMC11437681 DOI: 10.1186/s40246-024-00678-6] [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: 04/28/2024] [Accepted: 09/22/2024] [Indexed: 09/30/2024] Open
Abstract
Biological systems encompass intricate networks governed by RNA-protein interactions that play pivotal roles in cellular functions. RNA and proteins constituting 1.1% and 18% of the mammalian cell weight, respectively, orchestrate vital processes from genome organization to translation. To date, disentangling the functional fraction of the human genome has presented a major challenge, particularly for noncoding regions, yet recent discoveries have started to unveil a host of regulatory functions for noncoding RNAs (ncRNAs). While ncRNAs exist at different sizes, structures, degrees of evolutionary conservation and abundances within the cell, they partake in diverse roles either alone or in combination. However, certain ncRNA subtypes, including those that have been described or remain to be discovered, are poorly characterized given their heterogeneous nature. RNA activity is in most cases coordinated through interactions with RNA-binding proteins (RBPs). Extensive efforts are being made to accurately reconstruct RNA-RBP regulatory networks, which have provided unprecedented insight into cellular physiology and human disease. In this review, we provide a comprehensive view of RNAs and RBPs, focusing on how their interactions generate functional signals in living cells, particularly in the context of post-transcriptional regulatory processes and cancer.
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Affiliation(s)
- Carlos J Gallardo-Dodd
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
| | - Claudia Kutter
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden.
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4
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Rappol T, Waldl M, Chugunova A, Hofacker I, Pauli A, Vilardo E. tRNA expression and modification landscapes, and their dynamics during zebrafish embryo development. Nucleic Acids Res 2024; 52:10575-10594. [PMID: 38989621 PMCID: PMC11417395 DOI: 10.1093/nar/gkae595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 06/19/2024] [Accepted: 06/26/2024] [Indexed: 07/12/2024] Open
Abstract
tRNA genes exist in multiple copies in the genome of all organisms across the three domains of life. Besides the sequence differences across tRNA copies, extensive post-transcriptional modification adds a further layer to tRNA diversification. Whilst the crucial role of tRNAs as adapter molecules in protein translation is well established, whether all tRNAs are actually expressed, and whether the differences across isodecoders play any regulatory role is only recently being uncovered. Here we built upon recent developments in the use of NGS-based methods for RNA modification detection and developed tRAM-seq, an experimental protocol and in silico analysis pipeline to investigate tRNA expression and modification. Using tRAM-seq, we analysed the full ensemble of nucleo-cytoplasmic and mitochondrial tRNAs during embryonic development of the model vertebrate zebrafish. We show that the repertoire of tRNAs changes during development, with an apparent major switch in tRNA isodecoder expression and modification profile taking place around the start of gastrulation. Taken together, our findings suggest the existence of a general reprogramming of the expressed tRNA pool, possibly gearing the translational machinery for distinct stages of the delicate and crucial process of embryo development.
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Affiliation(s)
- Tom Rappol
- Center for Anatomy & Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | - Maria Waldl
- Center for Anatomy & Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
- Department of Theoretical Chemistry, University of Vienna, 1090 Vienna, Austria
- Vienna Doctoral School in Chemistry (DoSChem), University of Vienna, 1090 Vienna, Austria
- Institute of Computer Science and Interdisciplinary Center for Bioinformatics, Leipzig University, D-04107 Leipzig, Germany
| | - Anastasia Chugunova
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Ivo L Hofacker
- Department of Theoretical Chemistry, University of Vienna, 1090 Vienna, Austria
- Faculty of Computer Science, Research Group Bioinformatics and Computational Biology, University of Vienna, 1090 Vienna, Austria
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Elisa Vilardo
- Center for Anatomy & Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
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5
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Kapur M, Molumby MJ, Guzman C, Heinz S, Ackerman SL. Cell-type-specific expression of tRNAs in the brain regulates cellular homeostasis. Neuron 2024; 112:1397-1415.e6. [PMID: 38377989 PMCID: PMC11065635 DOI: 10.1016/j.neuron.2024.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 12/23/2023] [Accepted: 01/29/2024] [Indexed: 02/22/2024]
Abstract
Defects in tRNA biogenesis are associated with multiple neurological disorders, yet our understanding of these diseases has been hampered by an inability to determine tRNA expression in individual cell types within a complex tissue. Here, we developed a mouse model in which RNA polymerase III is conditionally epitope tagged in a Cre-dependent manner, allowing us to accurately profile tRNA expression in any cell type in vivo. We investigated tRNA expression in diverse nervous system cell types, revealing dramatic heterogeneity in the expression of tRNA genes between populations. We found that while maintenance of levels of tRNA isoacceptor families is critical for cellular homeostasis, neurons are differentially vulnerable to insults to distinct tRNA isoacceptor families. Cell-type-specific translatome analysis suggests that the balance between tRNA availability and codon demand may underlie such differential resilience. Our work provides a platform for investigating the complexities of mRNA translation and tRNA biology in the brain.
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Affiliation(s)
- Mridu Kapur
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute
| | - Michael J Molumby
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute
| | - Carlos Guzman
- Department of Medicine, Division of Endocrinology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, Bioinformatics & Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sven Heinz
- Department of Medicine, Division of Endocrinology, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Bioengineering, Bioinformatics & Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA; The Howard Hughes Medical Institute; Department of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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6
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Geng K, Merino LG, Veiga RG, Sommerauer C, Epperlein J, Brinkman EK, Kutter C. Intrinsic deletion at 10q23.31, including the PTEN gene locus, is aggravated upon CRISPR-Cas9-mediated genome engineering in HAP1 cells mimicking cancer profiles. Life Sci Alliance 2024; 7:e202302128. [PMID: 37984988 PMCID: PMC10662290 DOI: 10.26508/lsa.202302128] [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: 05/02/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/22/2023] Open
Abstract
The CRISPR-Cas9 system is a powerful tool for studying gene functions and holds potential for disease treatment. However, precise genome editing requires thorough assessments to minimize unintended on- and off-target effects. Here, we report an unexpected 283-kb deletion on Chromosome 10 (10q23.31) in chronic myelogenous leukemia-derived HAP1 cells, which are frequently used in CRISPR screens. The deleted region encodes regulatory genes, including PAPSS2, ATAD1, KLLN, and PTEN We found that this deletion was not a direct consequence of CRISPR-Cas9 off-targeting but rather occurred frequently during the generation of CRISPR-Cas9-modified cells. The deletion was associated with global changes in histone acetylation and gene expression, affecting fundamental cellular processes such as cell cycle and DNA replication. We detected this deletion in cancer patient genomes. As in HAP1 cells, the deletion contributed to similar gene expression patterns among cancer patients despite interindividual differences. Our findings suggest that the unintended deletion of 10q23.31 can confound CRISPR-Cas9 studies and underscore the importance to assess unintended genomic changes in CRISPR-Cas9-modified cells, which could impact cancer research.
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Affiliation(s)
- Keyi Geng
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
| | - Lara G Merino
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
| | - Raül G Veiga
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
| | - Christian Sommerauer
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
| | - Janine Epperlein
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
| | - Eva K Brinkman
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
| | - Claudia Kutter
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Solna, Sweden
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7
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Gao L, Behrens A, Rodschinka G, Forcelloni S, Wani S, Strasser K, Nedialkova DD. Selective gene expression maintains human tRNA anticodon pools during differentiation. Nat Cell Biol 2024; 26:100-112. [PMID: 38191669 PMCID: PMC10791582 DOI: 10.1038/s41556-023-01317-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 11/16/2023] [Indexed: 01/10/2024]
Abstract
Transfer RNAs are essential for translating genetic information into proteins. The human genome contains hundreds of predicted tRNA genes, many in multiple copies. How their expression is regulated to control tRNA repertoires is unknown. Here we combined quantitative tRNA profiling and chromatin immunoprecipitation with sequencing to measure tRNA expression following the differentiation of human induced pluripotent stem cells into neuronal and cardiac cells. We find that tRNA transcript levels vary substantially, whereas tRNA anticodon pools, which govern decoding rates, are more stable among cell types. Mechanistically, RNA polymerase III transcribes a wide range of tRNA genes in human induced pluripotent stem cells but on differentiation becomes constrained to a subset we define as housekeeping tRNAs. This shift is mediated by decreased mTORC1 signalling, which activates the RNA polymerase III repressor MAF1. Our data explain how tRNA anticodon pools are buffered to maintain decoding speed across cell types and reveal that mTORC1 drives selective tRNA expression during differentiation.
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Affiliation(s)
- Lexi Gao
- Mechanisms of Protein Biogenesis, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Andrew Behrens
- Mechanisms of Protein Biogenesis, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Geraldine Rodschinka
- Mechanisms of Protein Biogenesis, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Sergio Forcelloni
- Mechanisms of Protein Biogenesis, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Sascha Wani
- Mechanisms of Protein Biogenesis, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Katrin Strasser
- Mechanisms of Protein Biogenesis, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Danny D Nedialkova
- Mechanisms of Protein Biogenesis, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Department of Bioscience, TUM School of Natural Sciences, Technical University of Munich, Garching, Germany.
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8
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Valášek LS, Kučerová M, Zeman J, Beznosková P. Cysteine tRNA acts as a stop codon readthrough-inducing tRNA in the human HEK293T cell line. RNA (NEW YORK, N.Y.) 2023; 29:1379-1387. [PMID: 37221013 PMCID: PMC10573299 DOI: 10.1261/rna.079688.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/12/2023] [Indexed: 05/25/2023]
Abstract
Under certain circumstances, any of the three termination codons can be read through by a near-cognate tRNA; i.e., a tRNA whose two out of three anticodon nucleotides base pair with those of the stop codon. Unless programed to synthetize C-terminally extended protein variants with expanded physiological roles, readthrough represents an undesirable translational error. On the other side of a coin, a significant number of human genetic diseases is associated with the introduction of nonsense mutations (premature termination codons [PTCs]) into coding sequences, where stopping is not desirable. Here, the tRNA's ability to induce readthrough opens up the intriguing possibility of mitigating the deleterious effects of PTCs on human health. In yeast, the UGA and UAR stop codons were described to be read through by four readthrough-inducing rti-tRNAs-tRNATrp and tRNACys, and tRNATyr and tRNAGln, respectively. The readthrough-inducing potential of tRNATrp and tRNATyr was also observed in human cell lines. Here, we investigated the readthrough-inducing potential of human tRNACys in the HEK293T cell line. The tRNACys family consists of two isoacceptors, one with ACA and the other with GCA anticodons. We selected nine representative tRNACys isodecoders (differing in primary sequence and expression level) and tested them using dual luciferase reporter assays. We found that at least two tRNACys can significantly elevate UGA readthrough when overexpressed. This indicates a mechanistically conserved nature of rti-tRNAs between yeast and human, supporting the idea that they could be used in the PTC-associated RNA therapies.
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MESH Headings
- Humans
- Codon, Terminator/genetics
- Cysteine/genetics
- Cysteine/metabolism
- HEK293 Cells
- Saccharomyces cerevisiae/genetics
- RNA, Transfer, Cys/metabolism
- RNA, Transfer, Trp/metabolism
- RNA, Transfer, Tyr
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Anticodon
- Codon, Nonsense/genetics
- Protein Biosynthesis
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Affiliation(s)
- Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, 142 20 Prague, the Czech Republic
| | - Michaela Kučerová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, 142 20 Prague, the Czech Republic
| | - Jakub Zeman
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, 142 20 Prague, the Czech Republic
| | - Petra Beznosková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, 142 20 Prague, the Czech Republic
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9
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Nicolet BP, Wolkers MC. The relationship of mRNA with protein expression in CD8+ T cells associates with gene class and gene characteristics. PLoS One 2022; 17:e0276294. [PMID: 36260607 PMCID: PMC9581405 DOI: 10.1371/journal.pone.0276294] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 10/04/2022] [Indexed: 11/19/2022] Open
Abstract
T cells are key players in our defence against infections and malignancies. When T cells differentiate or become activated, they undergo substantial alterations in gene expression. Even though RNA expression levels are now well documented throughout different stages of T cells, it is not well understood how mRNA expression translates into the protein landscape. By combining paired RNA sequencing and mass spectrometry data of primary human CD8+ T cells, we report that mRNA expression is a poor proxy for the overall protein output, irrespective of the differentiation or activation status. Yet, gene class stratification revealed a function-specific correlation of mRNA with protein expression. This gene class-specific expression pattern associated with differences in gene characteristics such as sequence conservation and untranslated region (UTR) lengths. In addition, the presence of AU-rich elements in the 3'UTR associated with alterations in mRNA and protein abundance T cell activation dependent, gene class-specific manner. In conclusion, our study highlights the role of gene characteristics as a determinant for gene expression in T cells.
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Affiliation(s)
- Benoît P. Nicolet
- Department of Hematopoiesis, Sanquin Research, Amsterdam, The Netherlands
- Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
| | - Monika C. Wolkers
- Department of Hematopoiesis, Sanquin Research, Amsterdam, The Netherlands
- Landsteiner Laboratory, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Oncode Institute, Utrecht, The Netherlands
- * E-mail:
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10
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Geng K, Merino LG, Wedemann L, Martens A, Sobota M, Sanchez YP, Søndergaard JN, White RJ, Kutter C. Target-enriched nanopore sequencing and de novo assembly reveals co-occurrences of complex on-target genomic rearrangements induced by CRISPR-Cas9 in human cells. Genome Res 2022; 32:1876-1891. [PMID: 36180232 PMCID: PMC9712622 DOI: 10.1101/gr.276901.122] [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: 05/05/2022] [Accepted: 09/19/2022] [Indexed: 11/24/2022]
Abstract
The CRISPR-Cas9 system is widely used to permanently delete genomic regions via dual guide RNAs. Genomic rearrangements induced by CRISPR-Cas9 can occur, but continuous technical developments make it possible to characterize complex on-target effects. We combined an innovative droplet-based target enrichment approach with long-read sequencing and coupled it to a customized de novo sequence assembly. This approach enabled us to dissect the sequence content at kilobase scale within an on-target genomic locus. We here describe extensive genomic disruptions by Cas9, involving the allelic co-occurrence of a genomic duplication and inversion of the target region, as well as integrations of exogenous DNA and clustered interchromosomal DNA fragment rearrangements. Furthermore, we found that these genomic alterations led to functional aberrant DNA fragments and can alter cell proliferation. Our findings broaden the consequential spectrum of the Cas9 deletion system, reinforce the necessity of meticulous genomic validations, and introduce a data-driven workflow enabling detailed dissection of the on-target sequence content with superior resolution.
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Affiliation(s)
- Keyi Geng
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Lara G Merino
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Linda Wedemann
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Aniek Martens
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Małgorzata Sobota
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Yerma P Sanchez
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Jonas Nørskov Søndergaard
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
| | - Robert J White
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Claudia Kutter
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 65, Stockholm, Sweden
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11
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Miller JB, Meurs TE, Hodgman MW, Song B, Miller KN, Ebbert MTW, Kauwe JSK, Ridge PG. The Ramp Atlas: facilitating tissue and cell-specific ramp sequence analyses through an intuitive web interface. NAR Genom Bioinform 2022; 4:lqac039. [PMID: 35664804 PMCID: PMC9155233 DOI: 10.1093/nargab/lqac039] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 03/01/2022] [Accepted: 05/24/2022] [Indexed: 11/14/2022] Open
Abstract
Ramp sequences occur when the average translational efficiency of codons near the 5′ end of highly expressed genes is significantly lower than the rest of the gene sequence, which counterintuitively increases translational efficiency by decreasing downstream ribosomal collisions. Here, we show that the relative codon adaptiveness within different tissues changes the existence of a ramp sequence without altering the underlying genetic code. We present the first comprehensive analysis of tissue and cell type-specific ramp sequences and report 3108 genes with ramp sequences that change between tissues and cell types, which corresponds with increased gene expression within those tissues and cells. The Ramp Atlas (https://ramps.byu.edu/) allows researchers to query precomputed ramp sequences in 18 388 genes across 62 tissues and 66 cell types and calculate tissue-specific ramp sequences from user-uploaded FASTA files through an intuitive web interface. We used The Ramp Atlas to identify seven SARS-CoV-2 genes and seven human SARS-CoV-2 entry factor genes with tissue-specific ramp sequences that may help explain viral proliferation within those tissues. We anticipate that The Ramp Atlas will facilitate personalized and creative tissue-specific ramp sequence analyses for both human and viral genes that will increase our ability to utilize this often-overlooked regulatory region.
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Affiliation(s)
- Justin B Miller
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40504, USA
| | - Taylor E Meurs
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
| | - Matthew W Hodgman
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40504, USA
| | - Benjamin Song
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
| | - Kyle N Miller
- Department of Computer Science, Utah Valley University, Orem, UT 84058, USA
| | - Mark T W Ebbert
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY 40504, USA
| | - John S K Kauwe
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
| | - Perry G Ridge
- Department of Biology, Brigham Young University, Provo, UT 84602, USA
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12
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Søndergaard JN, Sommerauer C, Atanasoai I, Hinte LC, Geng K, Guiducci G, Bräutigam L, Aouadi M, Stojic L, Barragan I, Kutter C. CCT3- LINC00326 axis regulates hepatocarcinogenic lipid metabolism. Gut 2022; 71:gutjnl-2021-325109. [PMID: 35022268 PMCID: PMC9484377 DOI: 10.1136/gutjnl-2021-325109] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 12/09/2021] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To better comprehend transcriptional phenotypes of cancer cells, we globally characterised RNA-binding proteins (RBPs) to identify altered RNAs, including long non-coding RNAs (lncRNAs). DESIGN To unravel RBP-lncRNA interactions in cancer, we curated a list of ~2300 highly expressed RBPs in human cells, tested effects of RBPs and lncRNAs on patient survival in multiple cohorts, altered expression levels, integrated various sequencing, molecular and cell-based data. RESULTS High expression of RBPs negatively affected patient survival in 21 cancer types, especially hepatocellular carcinoma (HCC). After knockdown of the top 10 upregulated RBPs and subsequent transcriptome analysis, we identified 88 differentially expressed lncRNAs, including 34 novel transcripts. CRISPRa-mediated overexpression of four lncRNAs had major effects on the HCC cell phenotype and transcriptome. Further investigation of four RBP-lncRNA pairs revealed involvement in distinct regulatory processes. The most noticeable RBP-lncRNA connection affected lipid metabolism, whereby the non-canonical RBP CCT3 regulated LINC00326 in a chaperonin-independent manner. Perturbation of the CCT3-LINC00326 regulatory network led to decreased lipid accumulation and increased lipid degradation in cellulo as well as diminished tumour growth in vivo. CONCLUSIONS We revealed that RBP gene expression is perturbed in HCC and identified that RBPs exerted additional functions beyond their tasks under normal physiological conditions, which can be stimulated or intensified via lncRNAs and affected tumour growth.
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Affiliation(s)
- Jonas Nørskov Søndergaard
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Christian Sommerauer
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Ionut Atanasoai
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Laura C Hinte
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Keyi Geng
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Giulia Guiducci
- Barts Cancer Institute, Centre for Cancer Cell and Molecular Biology, John Vane Science Centre, Queen Mary University of London, London, UK
| | - Lars Bräutigam
- Comparative Medicine, Karolinska Institute, Stockholm, Sweden
| | - Myriam Aouadi
- Department of Medicine, Karolinska Institute, Stockholm, Sweden
| | - Lovorka Stojic
- Barts Cancer Institute, Centre for Cancer Cell and Molecular Biology, John Vane Science Centre, Queen Mary University of London, London, UK
| | - Isabel Barragan
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Claudia Kutter
- Department of Microbiology, Tumor, and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
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13
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Gao W, Gallardo-Dodd CJ, Kutter C. Cell type-specific analysis by single-cell profiling identifies a stable mammalian tRNA-mRNA interface and increased translation efficiency in neurons. Genome Res 2021; 32:97-110. [PMID: 34857654 PMCID: PMC8744671 DOI: 10.1101/gr.275944.121] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/24/2021] [Indexed: 11/24/2022]
Abstract
The correlation between codon and anticodon pools influences the efficiency of translation, but whether differences exist in these pools across individual cells is unknown. We determined that codon usage and amino acid demand are highly stable across different cell types using available mouse and human single-cell RNA-sequencing atlases. After showing the robustness of ATAC-sequencing measurements for the analysis of tRNA gene usage, we quantified anticodon usage and amino acid supply in both mouse and human single-cell ATAC-seq atlases. We found that tRNA gene usage is overall coordinated across cell types, except in neurons, which clustered separately from other cell types. Integration of these data sets revealed a strong and statistically significant correlation between amino acid supply and demand across almost all cell types. Neurons have an enhanced translation efficiency over other cell types, driven by an increased supply of tRNAAla (AGC) anticodons. This results in faster decoding of the Ala-GCC codon, as determined by cell type–specific ribosome profiling, suggesting that the reduction of tRNAAla (AGC) anticodon pools may be implicated in neurological pathologies. This study, the first such examination of codon usage, anticodon usage, and translation efficiency resolved at the cell-type level with single-cell information, identifies a conserved landscape of translation elongation across mammalian cellular diversity and evolution.
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Affiliation(s)
- William Gao
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 77, Stockholm, Sweden
| | - Carlos J Gallardo-Dodd
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 77, Stockholm, Sweden
| | - Claudia Kutter
- Department of Microbiology, Tumor, and Cell Biology, Karolinska Institute, Science for Life Laboratory, 171 77, Stockholm, Sweden
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14
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Morris C, Cluet D, Ricci EP. Ribosome dynamics and mRNA turnover, a complex relationship under constant cellular scrutiny. WILEY INTERDISCIPLINARY REVIEWS. RNA 2021; 12:e1658. [PMID: 33949788 PMCID: PMC8519046 DOI: 10.1002/wrna.1658] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 12/01/2022]
Abstract
Eukaryotic gene expression is closely regulated by translation and turnover of mRNAs. Recent advances highlight the importance of translation in the control of mRNA degradation, both for aberrant and apparently normal mRNAs. During translation, the information contained in mRNAs is decoded by ribosomes, one codon at a time, and tRNAs, by specifically recognizing codons, translate the nucleotide code into amino acids. Such a decoding step does not process regularly, with various obstacles that can hinder ribosome progression, then leading to ribosome stalling or collisions. The progression of ribosomes is constantly monitored by the cell which has evolved several translation-dependent mRNA surveillance pathways, including nonsense-mediated decay (NMD), no-go decay (NGD), and non-stop decay (NSD), to degrade certain problematic mRNAs and the incomplete protein products. Recent progress in sequencing and ribosome profiling has made it possible to discover new mechanisms controlling ribosome dynamics, with numerous crosstalks between translation and mRNA decay. We discuss here various translation features critical for mRNA decay, with particular focus on current insights from the complexity of the genetic code and also the emerging role for the ribosome as a regulatory hub orchestrating mRNA decay, quality control, and stress signaling. Even if the interplay between mRNA translation and degradation is no longer to be demonstrated, a better understanding of their precise coordination is worthy of further investigation. This article is categorized under: RNA Turnover and Surveillance > Regulation of RNA Stability Translation > Translation Regulation RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Christelle Morris
- Laboratory of Biology and Modeling of the CellUniversité de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR 5239, Inserm U1293LyonFrance
| | - David Cluet
- Laboratory of Biology and Modeling of the CellUniversité de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR 5239, Inserm U1293LyonFrance
| | - Emiliano P. Ricci
- Laboratory of Biology and Modeling of the CellUniversité de Lyon, ENS de Lyon, Université Claude Bernard, CNRS UMR 5239, Inserm U1293LyonFrance
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15
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Gillen SL, Waldron JA, Bushell M. Codon optimality in cancer. Oncogene 2021; 40:6309-6320. [PMID: 34584217 PMCID: PMC8585667 DOI: 10.1038/s41388-021-02022-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/24/2021] [Accepted: 09/10/2021] [Indexed: 12/14/2022]
Abstract
A key characteristic of cancer cells is their increased proliferative capacity, which requires elevated levels of protein synthesis. The process of protein synthesis involves the translation of codons within the mRNA coding sequence into a string of amino acids to form a polypeptide chain. As most amino acids are encoded by multiple codons, the nucleotide sequence of a coding region can vary dramatically without altering the polypeptide sequence of the encoded protein. Although mutations that do not alter the final amino acid sequence are often thought of as silent/synonymous, these can still have dramatic effects on protein output. Because each codon has a distinct translation elongation rate and can differentially impact mRNA stability, each codon has a different degree of 'optimality' for protein synthesis. Recent data demonstrates that the codon preference of a transcriptome matches the abundance of tRNAs within the cell and that this supply and demand between tRNAs and mRNAs varies between different cell types. The largest observed distinction is between mRNAs encoding proteins associated with proliferation or differentiation. Nevertheless, precisely how codon optimality and tRNA expression levels regulate cell fate decisions and their role in malignancy is not fully understood. This review describes the current mechanistic understanding on codon optimality, its role in malignancy and discusses the potential to target codon optimality therapeutically in the context of cancer.
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Affiliation(s)
- Sarah L Gillen
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
| | - Joseph A Waldron
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - Martin Bushell
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK, G61 1QH.
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16
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Kusnadi EP, Timpone C, Topisirovic I, Larsson O, Furic L. Regulation of gene expression via translational buffering. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1869:119140. [PMID: 34599983 DOI: 10.1016/j.bbamcr.2021.119140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 09/19/2021] [Accepted: 09/21/2021] [Indexed: 12/28/2022]
Abstract
Translation of an mRNA represents a critical step during the expression of protein-coding genes. As mechanisms governing post-transcriptional regulation of gene expression are progressively unveiled, it is becoming apparent that transcriptional programs are not fully reflected in the proteome. Herein, we highlight a previously underappreciated post-transcriptional mode of regulation of gene expression termed translational buffering. In principle, translational buffering opposes the impact of alterations in mRNA levels on the proteome. We further describe three types of translational buffering: compensation, which maintains protein levels e.g. across species or individuals; equilibration, which retains pathway stoichiometry; and offsetting, which acts as a reversible mechanism that maintains the levels of selected subsets of proteins constant despite genetic alteration and/or stress-induced changes in corresponding mRNA levels. While mechanisms underlying compensation and equilibration have been reviewed elsewhere, the principal focus of this review is on the less-well understood mechanism of translational offsetting. Finally, we discuss potential roles of translational buffering in homeostasis and disease.
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Affiliation(s)
- Eric P Kusnadi
- Translational Prostate Cancer Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia; Cancer Program, Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Clelia Timpone
- Translational Prostate Cancer Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Ivan Topisirovic
- Lady Davis Institute, Gerald Bronfman Department of Oncology and Departments of Biochemistry and Experimental Medicine, McGill University, Montreal, QC, Canada.
| | - Ola Larsson
- Science for Life Laboratory, Department of Oncology-Pathology, Karolinska Institutet, Solna, Sweden.
| | - Luc Furic
- Translational Prostate Cancer Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia; Cancer Program, Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia.
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17
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Acton RJ, Yuan W, Gao F, Xia Y, Bourne E, Wozniak E, Bell J, Lillycrop K, Wang J, Dennison E, Harvey NC, Mein CA, Spector TD, Hysi PG, Cooper C, Bell CG. The genomic loci of specific human tRNA genes exhibit ageing-related DNA hypermethylation. Nat Commun 2021; 12:2655. [PMID: 33976121 PMCID: PMC8113476 DOI: 10.1038/s41467-021-22639-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 03/05/2021] [Indexed: 02/03/2023] Open
Abstract
The epigenome has been shown to deteriorate with age, potentially impacting on ageing-related disease. tRNA, while arising from only ˜46 kb (<0.002% genome), is the second most abundant cellular transcript. tRNAs also control metabolic processes known to affect ageing, through core translational and additional regulatory roles. Here, we interrogate the DNA methylation state of the genomic loci of human tRNA. We identify a genomic enrichment for age-related DNA hypermethylation at tRNA loci. Analysis in 4,350 MeDIP-seq peripheral-blood DNA methylomes (16-82 years), identifies 44 and 21 hypermethylating specific tRNAs at study-and genome-wide significance, respectively, contrasting with none hypomethylating. Validation and replication (450k array and independent targeted Bisuphite-sequencing) supported the hypermethylation of this functional unit. Tissue-specificity is a significant driver, although the strongest consistent signals, also independent of major cell-type change, occur in tRNA-iMet-CAT-1-4 and tRNA-Ser-AGA-2-6. This study presents a comprehensive evaluation of the genomic DNA methylation state of human tRNA genes and reveals a discreet hypermethylation with advancing age.
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Affiliation(s)
- Richard J Acton
- William Harvey Research Institute, Barts & The London School of Medicine and Dentistry, Charterhouse Square, Queen Mary University of London, London, UK
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
- Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - Wei Yuan
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
- Institute of Cancer Research, Sutton, UK
| | - Fei Gao
- BGI-Shenzhen, Shenzhen, China
| | | | - Emma Bourne
- Barts & The London Genome Centre, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Eva Wozniak
- Barts & The London Genome Centre, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Jordana Bell
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
| | - Karen Lillycrop
- Human Development and Health, Institute of Developmental Sciences, University of Southampton, Southampton, UK
| | - Jun Wang
- Shenzhen Digital Life Institute, Shenzhen, Guangdong, China
- iCarbonX, Zhuhai, Guangdong, China
- State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macau, China
| | - Elaine Dennison
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
| | - Nicholas C Harvey
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
| | - Charles A Mein
- Barts & The London Genome Centre, Blizard Institute, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Tim D Spector
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
| | - Pirro G Hysi
- Department of Twin Research & Genetic Epidemiology, St Thomas Hospital, King's College London, London, UK
| | - Cyrus Cooper
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK
| | - Christopher G Bell
- William Harvey Research Institute, Barts & The London School of Medicine and Dentistry, Charterhouse Square, Queen Mary University of London, London, UK.
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18
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Wu B, Qiao J, Wang X, Liu M, Xu S, Sun D. Factors affecting the rapid changes of protein under short-term heat stress. BMC Genomics 2021; 22:263. [PMID: 33849452 PMCID: PMC8042900 DOI: 10.1186/s12864-021-07560-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 03/26/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Protein content determines the state of cells. The variation in protein abundance is crucial when organisms are in the early stages of heat stress, but the reasons affecting their changes are largely unknown. RESULTS We quantified 47,535 mRNAs and 3742 proteins in the filling grains of wheat in two different thermal environments. The impact of mRNA abundance and sequence features involved in protein translation and degradation on protein expression was evaluated by regression analysis. Transcription, codon usage and amino acid frequency were the main drivers of changes in protein expression under heat stress, and their combined contribution explains 58.2 and 66.4% of the protein variation at 30 and 40 °C (20 °C as control), respectively. Transcription contributes more to alterations in protein content at 40 °C (31%) than at 30 °C (6%). Furthermore, the usage of codon AAG may be closely related to the rapid alteration of proteins under heat stress. The contributions of AAG were 24 and 13% at 30 and 40 °C, respectively. CONCLUSION In this study, we analyzed the factors affecting the changes in protein expression in the early stage of heat stress and evaluated their influence.
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Affiliation(s)
- Bingjin Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Jianwen Qiao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Xiaoming Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Manshuang Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Shengbao Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
| | - Daojie Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, 712100 Shaanxi China
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19
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Whittle CA, Kulkarni A, Chung N, Extavour CG. Adaptation of codon and amino acid use for translational functions in highly expressed cricket genes. BMC Genomics 2021; 22:234. [PMID: 33823803 PMCID: PMC8022432 DOI: 10.1186/s12864-021-07411-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 01/27/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND For multicellular organisms, much remains unknown about the dynamics of synonymous codon and amino acid use in highly expressed genes, including whether their use varies with expression in different tissue types and sexes. Moreover, specific codons and amino acids may have translational functions in highly transcribed genes, that largely depend on their relationships to tRNA gene copies in the genome. However, these relationships and putative functions are poorly understood, particularly in multicellular systems. RESULTS Here, we studied codon and amino acid use in highly expressed genes from reproductive and nervous system tissues (male and female gonad, somatic reproductive system, brain and ventral nerve cord, and male accessory glands) in the cricket Gryllus bimaculatus. We report an optimal codon, defined as the codon preferentially used in highly expressed genes, for each of the 18 amino acids with synonymous codons in this organism. The optimal codons were mostly shared among tissue types and both sexes. However, the frequency of optimal codons was highest in gonadal genes. Concordant with translational selection, a majority of the optimal codons had abundant matching tRNA gene copies in the genome, but sometimes obligately required wobble tRNAs. We suggest the latter may comprise a mechanism for slowing translation of abundant transcripts, particularly for cell-cycle genes. Non-optimal codons, defined as those least commonly used in highly transcribed genes, intriguingly often had abundant tRNAs, and had elevated use in a subset of genes with specialized functions (gametic and apoptosis genes), suggesting their use promotes the translational upregulation of particular mRNAs. In terms of amino acids, we found evidence suggesting that amino acid frequency, tRNA gene copy number, and amino acid biosynthetic costs (size/complexity) had all interdependently evolved in this insect model, potentially for translational optimization. CONCLUSIONS Collectively, the results suggest a model whereby codon use in highly expressed genes, including optimal, wobble, and non-optimal codons, and their tRNA abundances, as well as amino acid use, have been influenced by adaptation for various functional roles in translation within this cricket. The effects of expression in different tissue types and the two sexes are discussed.
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Affiliation(s)
- Carrie A Whittle
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Arpita Kulkarni
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Nina Chung
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
| | - Cassandra G Extavour
- Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA.
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, 02138, MA, USA.
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20
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Ottenburghs J, Geng K, Suh A, Kutter C. Genome Size Reduction and Transposon Activity Impact tRNA Gene Diversity While Ensuring Translational Stability in Birds. Genome Biol Evol 2021; 13:6127176. [PMID: 33533905 PMCID: PMC8044555 DOI: 10.1093/gbe/evab016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2021] [Indexed: 12/12/2022] Open
Abstract
As a highly diverse vertebrate class, bird species have adapted to various ecological systems. How this phenotypic diversity can be explained genetically is intensively debated and is likely grounded in differences in the genome content. Larger and more complex genomes could allow for greater genetic regulation that results in more phenotypic variety. Surprisingly, avian genomes are much smaller compared to other vertebrates but contain as many protein-coding genes as other vertebrates. This supports the notion that the phenotypic diversity is largely determined by selection on non-coding gene sequences. Transfer RNAs (tRNAs) represent a group of non-coding genes. However, the characteristics of tRNA genes across bird genomes have remained largely unexplored. Here, we exhaustively investigated the evolution and functional consequences of these crucial translational regulators within bird species and across vertebrates. Our dense sampling of 55 avian genomes representing each bird order revealed an average of 169 tRNA genes with at least 31% being actively used. Unlike other vertebrates, avian tRNA genes are reduced in number and complexity but are still in line with vertebrate wobble pairing strategies and mutation-driven codon usage. Our detailed phylogenetic analyses further uncovered that new tRNA genes can emerge through multiplication by transposable elements. Together, this study provides the first comprehensive avian and cross-vertebrate tRNA gene analyses and demonstrates that tRNA gene evolution is flexible albeit constrained within functional boundaries of general mechanisms in protein translation.
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Affiliation(s)
- Jente Ottenburghs
- Department of Microbiology, Tumor and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden.,Department of Ecology and Genetics, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Sweden
| | - Keyi Geng
- Department of Microbiology, Tumor and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
| | - Alexander Suh
- Department of Ecology and Genetics, Evolutionary Biology Centre, Science for Life Laboratory, Uppsala University, Sweden
| | - Claudia Kutter
- Department of Microbiology, Tumor and Cell Biology, Science for Life Laboratory, Karolinska Institute, Stockholm, Sweden
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21
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Yang Q, Lyu X, Zhao F, Liu Y. Effects of codon usage on gene expression are promoter context dependent. Nucleic Acids Res 2021; 49:818-831. [PMID: 33410890 PMCID: PMC7826287 DOI: 10.1093/nar/gkaa1253] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 12/16/2020] [Indexed: 12/21/2022] Open
Abstract
Codon usage bias is a universal feature of all genomes. Although codon usage has been shown to regulate mRNA and protein levels by influencing mRNA decay and transcription in eukaryotes, little or no genome-wide correlations between codon usage and mRNA levels are detected in mammalian cells, raising doubt on the significance of codon usage effect on gene expression. Here we show that gene-specific regulation reduces the genome-wide codon usage and mRNA correlations: Constitutively expressed genes exhibit much higher genome-wide correlations than differentially expressed genes from fungi to human cells. Using Drosophila S2 cells as a model system, we showed that the effect of codon usage on mRNA expression level is promoter-dependent. Regions downstream of the core promoters of differentially expressed genes can repress the codon usage effects on mRNA expression. An element in the Hsp70 promoter was identified to be necessary and sufficient for this inhibitory effect. The promoter-dependent codon usage effects on mRNA levels are regulated at the transcriptional level through modulation of histone modifications, nucleosome densities and premature termination. Together, our results demonstrate that promoters play a major role in determining whether codon usage influences gene expression and further establish the transcription-dependent codon usage effects on gene expression.
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Affiliation(s)
- Qian Yang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA
| | - Xueliang Lyu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA.,State Key Laboratory of Agricultural Microbiology, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Fangzhou Zhao
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA
| | - Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA
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22
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Liu Y, Yang Q, Zhao F. Synonymous but Not Silent: The Codon Usage Code for Gene Expression and Protein Folding. Annu Rev Biochem 2021; 90:375-401. [PMID: 33441035 DOI: 10.1146/annurev-biochem-071320-112701] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Codon usage bias, the preference for certain synonymous codons, is found in all genomes. Although synonymous mutations were previously thought to be silent, a large body of evidence has demonstrated that codon usage can play major roles in determining gene expression levels and protein structures. Codon usage influences translation elongation speed and regulates translation efficiency and accuracy. Adaptation of codon usage to tRNA expression determines the proteome landscape. In addition, codon usage biases result in nonuniform ribosome decoding rates on mRNAs, which in turn influence the cotranslational protein folding process that is critical for protein function in diverse biological processes. Conserved genome-wide correlations have also been found between codon usage and protein structures. Furthermore, codon usage is a major determinant of mRNA levels through translation-dependent effects on mRNA decay and translation-independent effects on transcriptional and posttranscriptional processes. Here, we discuss the multifaceted roles and mechanisms of codon usage in different gene regulatory processes.
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Affiliation(s)
- Yi Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040, USA;
| | - Qian Yang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040, USA;
| | - Fangzhou Zhao
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9040, USA;
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23
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Neelagandan N, Lamberti I, Carvalho HJF, Gobet C, Naef F. What determines eukaryotic translation elongation: recent molecular and quantitative analyses of protein synthesis. Open Biol 2020; 10:200292. [PMID: 33292102 PMCID: PMC7776565 DOI: 10.1098/rsob.200292] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/10/2020] [Indexed: 12/14/2022] Open
Abstract
Protein synthesis from mRNA is an energy-intensive and tightly controlled cellular process. Translation elongation is a well-coordinated, multifactorial step in translation that undergoes dynamic regulation owing to cellular state and environmental determinants. Recent studies involving genome-wide approaches have uncovered some crucial aspects of translation elongation including the mRNA itself and the nascent polypeptide chain. Additionally, these studies have fuelled quantitative and mathematical modelling of translation elongation. In this review, we provide a comprehensive overview of the key determinants of translation elongation. We discuss consequences of ribosome stalling or collision, and how the cells regulate translation in case of such events. Next, we review theoretical approaches and widely used mathematical models that have become an essential ingredient to interpret complex molecular datasets and study translation dynamics quantitatively. Finally, we review recent advances in live-cell reporter and related analysis techniques, to monitor the translation dynamics of single cells and single-mRNA molecules in real time.
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Affiliation(s)
| | | | | | | | - Felix Naef
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
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24
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Dhindsa RS, Copeland BR, Mustoe AM, Goldstein DB. Natural Selection Shapes Codon Usage in the Human Genome. Am J Hum Genet 2020; 107:83-95. [PMID: 32516569 PMCID: PMC7332603 DOI: 10.1016/j.ajhg.2020.05.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/12/2020] [Indexed: 01/06/2023] Open
Abstract
Synonymous codon usage has been identified as a determinant of translational efficiency and mRNA stability in model organisms and human cell lines. However, whether natural selection shapes human codon content to optimize translation efficiency is unclear. Furthermore, aside from those that affect splicing, synonymous mutations are typically ignored as potential contributors to disease. Using genetic sequencing data from nearly 200,000 individuals, we uncover clear evidence that natural selection optimizes codon content in the human genome. In deriving intolerance metrics to quantify gene-level constraint on synonymous variation, we discover that dosage-sensitive genes, DNA-damage-response genes, and cell-cycle-regulated genes are particularly intolerant to synonymous variation. Notably, we illustrate that reductions in codon optimality in BRCA1 can attenuate its function. Our results reveal that synonymous mutations most likely play an underappreciated role in human variation.
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Affiliation(s)
- Ryan S Dhindsa
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA; Integrated Program in Cellular, Molecular, and Biomedical Studies, Columbia University Irving Medical Center, New York, NY 10032, USA.
| | - Brett R Copeland
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Anthony M Mustoe
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - David B Goldstein
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY 10032, USA.
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25
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Gobet C, Weger BD, Marquis J, Martin E, Neelagandan N, Gachon F, Naef F. Robust landscapes of ribosome dwell times and aminoacyl-tRNAs in response to nutrient stress in liver. Proc Natl Acad Sci U S A 2020; 117:9630-9641. [PMID: 32295881 PMCID: PMC7196831 DOI: 10.1073/pnas.1918145117] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Translation depends on messenger RNA (mRNA)-specific initiation, elongation, and termination rates. While translation elongation is well studied in bacteria and yeast, less is known in higher eukaryotes. Here we combined ribosome and transfer RNA (tRNA) profiling to investigate the relations between translation elongation rates, (aminoacyl-) tRNA levels, and codon usage in mammals. We modeled codon-specific ribosome dwell times from ribosome profiling, considering codon pair interactions between ribosome sites. In mouse liver, the model revealed site- and codon-specific dwell times that differed from those in yeast, as well as pairs of adjacent codons in the P and A site that markedly slow down or speed up elongation. While translation efficiencies vary across diurnal time and feeding regimen, codon dwell times were highly stable and conserved in human. Measured tRNA levels correlated with codon usage and several tRNAs showed reduced aminoacylation, which was conserved in fasted mice. Finally, we uncovered that the longest codon dwell times could be explained by aminoacylation levels or high codon usage relative to tRNA abundance.
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Affiliation(s)
- Cédric Gobet
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Nestlé Research, CH-1015 Lausanne, Switzerland
| | - Benjamin Dieter Weger
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
- Nestlé Research, CH-1015 Lausanne, Switzerland
| | | | - Eva Martin
- Nestlé Research, CH-1015 Lausanne, Switzerland
| | - Nagammal Neelagandan
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | | | - Felix Naef
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland;
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26
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Mordstein C, Savisaar R, Young RS, Bazile J, Talmane L, Luft J, Liss M, Taylor MS, Hurst LD, Kudla G. Codon Usage and Splicing Jointly Influence mRNA Localization. Cell Syst 2020; 10:351-362.e8. [PMID: 32275854 PMCID: PMC7181179 DOI: 10.1016/j.cels.2020.03.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 12/19/2019] [Accepted: 03/05/2020] [Indexed: 12/11/2022]
Abstract
In the human genome, most genes undergo splicing, and patterns of codon usage are splicing dependent: guanine and cytosine (GC) content is the highest within single-exon genes and within first exons of multi-exon genes. However, the effects of codon usage on gene expression are typically characterized in unspliced model genes. Here, we measured the effects of splicing on expression in a panel of synonymous reporter genes that varied in nucleotide composition. We found that high GC content increased protein yield, mRNA yield, cytoplasmic mRNA localization, and translation of unspliced reporters. Splicing did not affect the expression of GC-rich variants. However, splicing promoted the expression of AT-rich variants by increasing their steady-state protein and mRNA levels, in part through promoting cytoplasmic localization of mRNA. We propose that splicing promotes the nuclear export of AU-rich mRNAs and that codon- and splicing-dependent effects on expression are under evolutionary pressure in the human genome.
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Affiliation(s)
- Christine Mordstein
- MRC Human Genetics Unit, Institute for Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK; Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Rosina Savisaar
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK; Instituto de Medicina Molecular, João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Robert S Young
- MRC Human Genetics Unit, Institute for Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK; Centre for Global Health Research, Usher Institute, The University of Edinburgh, Edinburgh, UK
| | - Jeanne Bazile
- MRC Human Genetics Unit, Institute for Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK
| | - Lana Talmane
- MRC Human Genetics Unit, Institute for Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK
| | - Juliet Luft
- MRC Human Genetics Unit, Institute for Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK
| | - Michael Liss
- Thermo Fisher Scientific, GENEART GmbH, Regensburg, Germany
| | - Martin S Taylor
- MRC Human Genetics Unit, Institute for Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK
| | - Laurence D Hurst
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Grzegorz Kudla
- MRC Human Genetics Unit, Institute for Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK.
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27
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Hernandez‐Alias X, Benisty H, Schaefer MH, Serrano L. Translational efficiency across healthy and tumor tissues is proliferation-related. Mol Syst Biol 2020; 16:e9275. [PMID: 32149479 PMCID: PMC7061310 DOI: 10.15252/msb.20199275] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/11/2020] [Accepted: 02/11/2020] [Indexed: 12/20/2022] Open
Abstract
Different tissues express genes with particular codon usage and anticodon tRNA repertoires. However, the codon-anticodon co-adaptation in humans is not completely understood, nor is its effect on tissue-specific protein levels. Here, we first validated the accuracy of small RNA-seq for tRNA quantification across five human cell lines. We then analyzed the tRNA abundance of more than 8,000 tumor samples from TCGA, together with their paired mRNA-seq and proteomics data, to determine the Supply-to-Demand Adaptation. We thereby elucidate that the dynamic adaptation of the tRNA pool is largely related to the proliferative state across tissues. The distribution of such tRNA pools over the whole cellular translatome affects the subsequent translational efficiency, which functionally determines a condition-specific expression program both in healthy and tumor states. Furthermore, the aberrant translational efficiency of some codons in cancer, exemplified by ProCCA and GlyGGT, is associated with poor patient survival. The regulation of these tRNA profiles is partly explained by the tRNA gene copy numbers and their promoter DNA methylation.
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Affiliation(s)
- Xavier Hernandez‐Alias
- Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Hannah Benisty
- Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyBarcelonaSpain
| | - Martin H Schaefer
- Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Department of Experimental OncologyIEO, European Institute of Oncology IRCCSMilanItaly
| | - Luis Serrano
- Centre for Genomic Regulation (CRG)The Barcelona Institute of Science and TechnologyBarcelonaSpain
- Universitat Pompeu Fabra (UPF)BarcelonaSpain
- ICREABarcelonaSpain
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28
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Guimaraes JC, Mittal N, Gnann A, Jedlinski D, Riba A, Buczak K, Schmidt A, Zavolan M. A rare codon-based translational program of cell proliferation. Genome Biol 2020; 21:44. [PMID: 32102681 PMCID: PMC7045563 DOI: 10.1186/s13059-020-1943-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 01/22/2020] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The speed of translation elongation is primarily determined by the abundance of tRNAs. Thus, the codon usage influences the rate with which individual mRNAs are translated. As the nature of tRNA pools and modifications can vary across biological conditions, codon elongation rates may also vary, leading to fluctuations in the protein production from individual mRNAs. Although it has been observed that functionally related mRNAs exhibit similar codon usage, presumably to provide an effective way to coordinate expression of multiple proteins, experimental evidence for codon-mediated translation efficiency modulation of functionally related mRNAs in specific conditions is scarce and the associated mechanisms are still debated. RESULTS Here, we reveal that mRNAs whose expression increases during cell proliferation are enriched in rare codons, poorly adapted to tRNA pools. Ribosome occupancy profiling and proteomics measurements show that upon increased cell proliferation, transcripts enriched in rare codons undergo a higher translation boost than transcripts with common codons. Re-coding of a fluorescent reporter with rare codons increased protein output by ~ 30% relative to a reporter re-coded with common codons. Although the translation capacity of proliferating cells was higher compared to resting cells, we did not find evidence for the regulation of individual tRNAs. Among the models that were proposed so far to account for codon-mediated translational regulation upon changing conditions, the one that seems most consistent with our data involves a global upregulation of ready-to-translate tRNAs, which we show can lead to a higher increase in the elongation velocity at rare codons compared to common codons. CONCLUSIONS We propose that the alleviation of translation bottlenecks in rapidly dividing cells enables preferential upregulation of pro-proliferation proteins, encoded by mRNAs that are enriched in rare codons.
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Affiliation(s)
- Joao C Guimaraes
- Computational and Systems Biology, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland.
| | - Nitish Mittal
- Computational and Systems Biology, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
| | - Alexandra Gnann
- Computational and Systems Biology, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
- Department of Biomedicine, University of Basel/University Hospital Basel, Hebelstrasse 20, 4031, Basel, Switzerland
| | - Dominik Jedlinski
- Computational and Systems Biology, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
| | - Andrea Riba
- Computational and Systems Biology, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Université de Strasbourg, 1 rue Laurent Fries, 67404, Illkirch CEDEX, France
| | - Katarzyna Buczak
- Proteomics Core Facility, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland
| | - Mihaela Zavolan
- Computational and Systems Biology, Biozentrum University of Basel, Klingelbergstrasse 50-70, 4056, Basel, Switzerland.
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29
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Chen J, Wang L, Wang F, Liu J, Bai Z. Genomic Identification of RNA Editing Through Integrating Omics Datasets and the Clinical Relevance in Hepatocellular Carcinoma. Front Oncol 2020; 10:37. [PMID: 32117713 PMCID: PMC7033493 DOI: 10.3389/fonc.2020.00037] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/09/2020] [Indexed: 12/12/2022] Open
Abstract
RNA editing is a widespread post-transcriptional mechanism to introduce single nucleotide changes to RNA in human cancers. Here, we characterized the global RNA editing profiles of 373 hepatocellular carcinoma (HCC) and 50 adjacent normal liver samples from The Cancer Genome Atlas (TCGA) and revealed that most editing events tend to occur in minor percentage of samples with moderate editing degrees (20–30%). Moreover, these RNA editing prefer to be A-to-I RNA editing in protein coding genes, especially in 3′UTR regions. Considering the association between DNA mutation and RNA editing, our analysis found that RNA editing maybe a complementary event for DNA mutation of HCC risk genes in HCC patients. We next identified 454 HCC-related editing sites, and many locate on the same genes with the same editing patterns. The functional consequences of editing revealed 2,086 functional editing sites and demonstrated that most editing in coding regions are non-synonymous variations. Furthermore, our results showed that editing in the 3′UTR regions tend to influence miRNA–target binding, and the editing degree seems to be negatively correlated with gene expression. Finally, we found that 46 HCC-related editing sites with consequence are able to distinguish the prognosis differences of HCC patients, suggesting their clinical relevance. Together, our results highlight RNA editing as a valuable molecular resource for investigating HCC mechanisms and clinical treatments.
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Affiliation(s)
- Juan Chen
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Lu Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Fangbin Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Jian Liu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China.,Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology, Hefei, China
| | - Zhenyu Bai
- Department of Laboratory, General Hospital of Pingmei Shenma Medical Group, Pingdingshan, China
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30
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Courel M, Clément Y, Bossevain C, Foretek D, Vidal Cruchez O, Yi Z, Bénard M, Benassy MN, Kress M, Vindry C, Ernoult-Lange M, Antoniewski C, Morillon A, Brest P, Hubstenberger A, Roest Crollius H, Standart N, Weil D. GC content shapes mRNA storage and decay in human cells. eLife 2019; 8:49708. [PMID: 31855182 PMCID: PMC6944446 DOI: 10.7554/elife.49708] [Citation(s) in RCA: 122] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 12/18/2019] [Indexed: 02/07/2023] Open
Abstract
mRNA translation and decay appear often intimately linked although the rules of this interplay are poorly understood. In this study, we combined our recent P-body transcriptome with transcriptomes obtained following silencing of broadly acting mRNA decay and repression factors, and with available CLIP and related data. This revealed the central role of GC content in mRNA fate, in terms of P-body localization, mRNA translation and mRNA stability: P-bodies contain mostly AU-rich mRNAs, which have a particular codon usage associated with a low protein yield; AU-rich and GC-rich transcripts tend to follow distinct decay pathways; and the targets of sequence-specific RBPs and miRNAs are also biased in terms of GC content. Altogether, these results suggest an integrated view of post-transcriptional control in human cells where most translation regulation is dedicated to inefficiently translated AU-rich mRNAs, whereas control at the level of 5’ decay applies to optimally translated GC-rich mRNAs.
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Affiliation(s)
- Maïté Courel
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Paris, France
| | - Yves Clément
- Ecole Normale Supérieure, Institut de Biologie de l'ENS, IBENS, Paris, France
| | - Clémentine Bossevain
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Paris, France
| | - Dominika Foretek
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, PSL Research University, CNRS UMR 3244, Sorbonne Université, Paris, France
| | | | - Zhou Yi
- Université Côte d'Azur, CNRS, INSERM, iBV, Nice, France
| | - Marianne Bénard
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Paris, France
| | - Marie-Noëlle Benassy
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Paris, France
| | - Michel Kress
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Paris, France
| | - Caroline Vindry
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Michèle Ernoult-Lange
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Paris, France
| | - Christophe Antoniewski
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), ARTbio Bioinformatics Analysis Facility, Paris, France
| | - Antonin Morillon
- ncRNA, Epigenetic and Genome Fluidity, Institut Curie, PSL Research University, CNRS UMR 3244, Sorbonne Université, Paris, France
| | - Patrick Brest
- Université Côte d'Azur, CNRS, INSERM, IRCAN, FHU-OncoAge, Nice, France
| | | | | | - Nancy Standart
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Dominique Weil
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine (IBPS), Laboratoire de Biologie du Développement, Paris, France
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31
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Yeganeh M, Praz V, Carmeli C, Villeneuve D, Rib L, Guex N, Herr W, Delorenzi M, Hernandez N. Differential regulation of RNA polymerase III genes during liver regeneration. Nucleic Acids Res 2019; 47:1786-1796. [PMID: 30597109 PMCID: PMC6393285 DOI: 10.1093/nar/gky1282] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/22/2018] [Accepted: 12/14/2018] [Indexed: 12/23/2022] Open
Abstract
Mouse liver regeneration after partial hepatectomy involves cells in the remaining tissue synchronously entering the cell division cycle. We have used this system and H3K4me3, Pol II and Pol III profiling to characterize adaptations in Pol III transcription. Our results broadly define a class of genes close to H3K4me3 and Pol II peaks, whose Pol III occupancy is high and stable, and another class, distant from Pol II peaks, whose Pol III occupancy strongly increases after partial hepatectomy. Pol III regulation in the liver thus entails both highly expressed housekeeping genes and genes whose expression can adapt to increased demand.
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Affiliation(s)
- Meghdad Yeganeh
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Viviane Praz
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland.,SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Cristian Carmeli
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland.,Bioinformatics Core Facility, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Dominic Villeneuve
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Leonor Rib
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Nicolas Guex
- SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Winship Herr
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Mauro Delorenzi
- Bioinformatics Core Facility, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.,Department of Fundamental Oncology and the Ludwig Center for Cancer research, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Nouria Hernandez
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
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32
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Davydov II, Salamin N, Robinson-Rechavi M. Large-Scale Comparative Analysis of Codon Models Accounting for Protein and Nucleotide Selection. Mol Biol Evol 2019; 36:1316-1332. [PMID: 30847475 PMCID: PMC6526913 DOI: 10.1093/molbev/msz048] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
There are numerous sources of variation in the rate of synonymous substitutions inside genes, such as direct selection on the nucleotide sequence, or mutation rate variation. Yet scans for positive selection rely on codon models which incorporate an assumption of effectively neutral synonymous substitution rate, constant between sites of each gene. Here we perform a large-scale comparison of approaches which incorporate codon substitution rate variation and propose our own simple yet effective modification of existing models. We find strong effects of substitution rate variation on positive selection inference. More than 70% of the genes detected by the classical branch-site model are presumably false positives caused by the incorrect assumption of uniform synonymous substitution rate. We propose a new model which is strongly favored by the data while remaining computationally tractable. With the new model we can capture signatures of nucleotide level selection acting on translation initiation and on splicing sites within the coding region. Finally, we show that rate variation is highest in the highly recombining regions, and we propose that recombination and mutation rate variation, such as high CpG mutation rate, are the two main sources of nucleotide rate variation. Although we detect fewer genes under positive selection in Drosophila than without rate variation, the genes which we detect contain a stronger signal of adaptation of dynein, which could be associated with Wolbachia infection. We provide software to perform positive selection analysis using the new model.
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Affiliation(s)
- Iakov I Davydov
- Department of Computational Biology, Biophore, University of Lausanne, Lausanne, Switzerland.,Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nicolas Salamin
- Department of Computational Biology, Biophore, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Marc Robinson-Rechavi
- Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
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33
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Payne BL, Alvarez-Ponce D. Codon Usage Differences among Genes Expressed in Different Tissues of Drosophila melanogaster. Genome Biol Evol 2019; 11:1054-1065. [PMID: 30859203 PMCID: PMC6456009 DOI: 10.1093/gbe/evz051] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2019] [Indexed: 12/22/2022] Open
Abstract
Codon usage patterns are affected by both mutational biases and translational selection. The frequency at which each codon is used in the genome is directly linked to the cellular concentrations of their corresponding tRNAs. Transfer RNA abundances—as well as the abundances of other potentially relevant factors, such as RNA-binding proteins—may vary across different tissues, making it possible that genes expressed in different tissues are subject to different translational selection regimes, and thus differ in their patterns of codon usage. These differences, however, are poorly understood, having been studied only in Arabidopsis, rice and human, with controversial results in human. Drosophila melanogaster is a suitable model organism to study tissue-specific codon adaptation given its large effective population size. Here, we compare 2,046 genes, each expressed specifically in one tissue of D. melanogaster. We show that genes expressed in different tissues exhibit significant differences in their patterns of codon usage, and that these differences are only partially due to differences in GC content, expression levels, or protein lengths. Remarkably, these differences are stronger when analyses are restricted to highly expressed genes. Our results strongly suggest that genes expressed in different tissues are subject to different regimes of translational selection.
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34
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Protein synthesis rates and ribosome occupancies reveal determinants of translation elongation rates. Proc Natl Acad Sci U S A 2019; 116:15023-15032. [PMID: 31292258 PMCID: PMC6660795 DOI: 10.1073/pnas.1817299116] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Although protein synthesis dynamics has been studied both with theoretical models and by profiling ribosome footprints, the determinants of ribosome flux along open reading frames (ORFs) are not fully understood. Combining measurements of protein synthesis rate with ribosome footprinting data, we here inferred translation initiation and elongation rates for over a 1,000 ORFs in exponentially growing wild-type yeast cells. We found that the amino acid composition of synthesized proteins is as important a determinant of translation elongation rate as parameters related to codon and transfer RNA (tRNA) adaptation. We did not find evidence of ribosome collisions curbing the protein output of yeast transcripts, either in high translation conditions associated with exponential growth, or in strains in which deletion of individual ribosomal protein (RP) genes leads to globally increased or decreased translation. Slow translation elongation is characteristic of RP-encoding transcripts, which have markedly lower protein output compared with other transcripts with equally high ribosome densities.
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35
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Bornelöv S, Selmi T, Flad S, Dietmann S, Frye M. Codon usage optimization in pluripotent embryonic stem cells. Genome Biol 2019; 20:119. [PMID: 31174582 PMCID: PMC6555954 DOI: 10.1186/s13059-019-1726-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/23/2019] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND The uneven use of synonymous codons in the transcriptome regulates the efficiency and fidelity of protein translation rates. Yet, the importance of this codon bias in regulating cell state-specific expression programmes is currently debated. Here, we ask whether different codon usage controls gene expression programmes in self-renewing and differentiating embryonic stem cells. RESULTS Using ribosome and transcriptome profiling, we identify distinct codon signatures during human embryonic stem cell differentiation. We find that cell state-specific codon bias is determined by the guanine-cytosine (GC) content of differentially expressed genes. By measuring the codon frequencies at the ribosome active sites interacting with transfer RNAs (tRNA), we further discover that self-renewing cells optimize translation of codons that depend on the inosine tRNA modification in the anticodon wobble position. Accordingly, inosine levels are highest in human pluripotent embryonic stem cells. This effect is conserved in mice and is independent of the differentiation stimulus. CONCLUSIONS We show that GC content influences cell state-specific mRNA levels, and we reveal how translational mechanisms based on tRNA modifications change codon usage in embryonic stem cells.
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Affiliation(s)
- Susanne Bornelöv
- Wellcome Trust - Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Tommaso Selmi
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Sophia Flad
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany
| | - Sabine Dietmann
- Wellcome Trust - Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QR, UK
| | - Michaela Frye
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
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36
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McQueen C, Hughes GL, Pownall ME. Skeletal muscle differentiation drives a dramatic downregulation of RNA polymerase III activity and differential expression of Polr3g isoforms. Dev Biol 2019; 454:74-84. [PMID: 31173763 DOI: 10.1016/j.ydbio.2019.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/09/2019] [Accepted: 06/03/2019] [Indexed: 12/27/2022]
Abstract
Gene regulatory networks underpinning skeletal muscle determination and differentiation have been extensively investigated, providing molecular insights into how cell lineages are established during development. These studies have exclusively focused on the transcriptome downstream of RNA polymerase II (Pol II). RNA polymerase III (Pol III) drives the production of tRNAs and other small RNAs essential for the flow of genetic information from gene to protein and we have found that a specific isoform of a subunit unique to Pol III is expressed early in the myogenic lineage. This points to the possibility that additional regulatory networks exist to control the production of Pol III transcripts during skeletal muscle differentiation. We describe the differential expression of Polr3g and its alternate isoform Polr3gL during embryonic development and using a custom tRNA microarray, we demonstrate their distinct activity on the synthesis of tRNA isoacceptors. We show that Pol III dependent transcripts are dramatically down-regulated during the differentiation of skeletal muscle, as are mRNAs coding for Pol III associated proteins Brf1 and Brf2, while Polr3gL is up-regulated alongside contractile protein genes. Forcing Polr3g expression in this context results in a partial reversal of myogenic differentiation.
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Affiliation(s)
- Caitlin McQueen
- Biology Department, University of York, York, YO10 5DD, United Kingdom
| | - Gideon L Hughes
- Biology Department, University of York, York, YO10 5DD, United Kingdom
| | - Mary E Pownall
- Biology Department, University of York, York, YO10 5DD, United Kingdom.
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37
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Galtier N, Roux C, Rousselle M, Romiguier J, Figuet E, Glémin S, Bierne N, Duret L. Codon Usage Bias in Animals: Disentangling the Effects of Natural Selection, Effective Population Size, and GC-Biased Gene Conversion. Mol Biol Evol 2019; 35:1092-1103. [PMID: 29390090 DOI: 10.1093/molbev/msy015] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Selection on codon usage bias is well documented in a number of microorganisms. Whether codon usage is also generally shaped by natural selection in large organisms, despite their relatively small effective population size (Ne), is unclear. In animals, the population genetics of codon usage bias has only been studied in a handful of model organisms so far, and can be affected by confounding, nonadaptive processes such as GC-biased gene conversion and experimental artefacts. Using population transcriptomics data, we analyzed the relationship between codon usage, gene expression, allele frequency distribution, and recombination rate in 30 nonmodel species of animals, each from a different family, covering a wide range of effective population sizes. We disentangled the effects of translational selection and GC-biased gene conversion on codon usage by separately analyzing GC-conservative and GC-changing mutations. We report evidence for effective translational selection on codon usage in large-Ne species of animals, but not in small-Ne ones, in agreement with the nearly neutral theory of molecular evolution. C- and T-ending codons tend to be preferred over synonymous G- and A-ending ones, for reasons that remain to be determined. In contrast, we uncovered a conspicuous effect of GC-biased gene conversion, which is widespread in animals and the main force determining the fate of AT↔GC mutations. Intriguingly, the strength of its effect was uncorrelated with Ne.
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Affiliation(s)
- Nicolas Galtier
- UMR5554, Institut des Sciences de l'Evolution, University Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Camille Roux
- UMR5554, Institut des Sciences de l'Evolution, University Montpellier, CNRS, IRD, EPHE, Montpellier, France.,Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.,UMR 8198 - Evo-Eco-Paleo, CNRS, Université de Lille-Sciences et Technologies, Villeneuve d'Ascq, France
| | - Marjolaine Rousselle
- UMR5554, Institut des Sciences de l'Evolution, University Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Jonathan Romiguier
- UMR5554, Institut des Sciences de l'Evolution, University Montpellier, CNRS, IRD, EPHE, Montpellier, France.,Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Emeric Figuet
- UMR5554, Institut des Sciences de l'Evolution, University Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Sylvain Glémin
- UMR5554, Institut des Sciences de l'Evolution, University Montpellier, CNRS, IRD, EPHE, Montpellier, France.,Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Nicolas Bierne
- UMR5554, Institut des Sciences de l'Evolution, University Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Laurent Duret
- Laboratoire de Biométrie et Biologie Evolutive, UMR 5558, CNRS, Université de Lyon, Université Lyon 1, Villeurbanne, France
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38
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Eraslan B, Wang D, Gusic M, Prokisch H, Hallström BM, Uhlén M, Asplund A, Pontén F, Wieland T, Hopf T, Hahne H, Kuster B, Gagneur J. Quantification and discovery of sequence determinants of protein-per-mRNA amount in 29 human tissues. Mol Syst Biol 2019; 15:e8513. [PMID: 30777893 PMCID: PMC6379048 DOI: 10.15252/msb.20188513] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 12/15/2022] Open
Abstract
Despite their importance in determining protein abundance, a comprehensive catalogue of sequence features controlling protein-to-mRNA (PTR) ratios and a quantification of their effects are still lacking. Here, we quantified PTR ratios for 11,575 proteins across 29 human tissues using matched transcriptomes and proteomes. We estimated by regression the contribution of known sequence determinants of protein synthesis and degradation in addition to 45 mRNA and 3 protein sequence motifs that we found by association testing. While PTR ratios span more than 2 orders of magnitude, our integrative model predicts PTR ratios at a median precision of 3.2-fold. A reporter assay provided functional support for two novel UTR motifs, and an immobilized mRNA affinity competition-binding assay identified motif-specific bound proteins for one motif. Moreover, our integrative model led to a new metric of codon optimality that captures the effects of codon frequency on protein synthesis and degradation. Altogether, this study shows that a large fraction of PTR ratio variation in human tissues can be predicted from sequence, and it identifies many new candidate post-transcriptional regulatory elements.
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Affiliation(s)
- Basak Eraslan
- Computational Biology, Department of Informatics, Technical University of Munich, Garching Munich, Germany
- Graduate School of Quantitative Biosciences (QBM), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Dongxue Wang
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
| | - Mirjana Gusic
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Holger Prokisch
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Björn M Hallström
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Mathias Uhlén
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden
| | - Anna Asplund
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Frederik Pontén
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Thomas Wieland
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
| | - Thomas Hopf
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
| | | | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technical University of Munich, Freising, Germany
- Center For Integrated Protein Science Munich (CIPSM), Munich, Germany
| | - Julien Gagneur
- Computational Biology, Department of Informatics, Technical University of Munich, Garching Munich, Germany
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39
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Comparative expression profiling reveals widespread coordinated evolution of gene expression across eukaryotes. Nat Commun 2018; 9:4963. [PMID: 30470754 PMCID: PMC6251915 DOI: 10.1038/s41467-018-07436-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 10/24/2018] [Indexed: 12/17/2022] Open
Abstract
Comparative studies of gene expression across species have revealed many important insights, but have also been limited by the number of species represented. Here we develop an approach to identify orthologs between highly diverged transcriptome assemblies, and apply this to 657 RNA-seq gene expression profiles from 309 diverse unicellular eukaryotes. We analyzed the resulting data for coevolutionary patterns, and identify several hundred protein complexes and pathways whose expression levels have evolved in a coordinated fashion across the trillions of generations separating these species, including many gene sets with little or no within-species co-expression across environmental or genetic perturbations. We also detect examples of adaptive evolution, for example of tRNA ligase levels to match genome-wide codon usage. In sum, we find that comparative studies from extremely diverse organisms can reveal new insights into the evolution of gene expression, including coordinated evolution of some of the most conserved protein complexes in eukaryotes. Gene pairs that are coexpressed across various environmental conditions in multiple species suggest functional similarity. Here the authors analyze patterns of gene expression co-evolution across diverse eukaryotes, and identify hundreds of protein complexes and pathways whose gene expression levels have co-evolved since their ancient divergence.
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40
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Chen L, Fish AE, Capra JA. Prediction of gene regulatory enhancers across species reveals evolutionarily conserved sequence properties. PLoS Comput Biol 2018; 14:e1006484. [PMID: 30286077 PMCID: PMC6191148 DOI: 10.1371/journal.pcbi.1006484] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 10/16/2018] [Accepted: 09/02/2018] [Indexed: 12/30/2022] Open
Abstract
Genomic regions with gene regulatory enhancer activity turnover rapidly across mammals. In contrast, gene expression patterns and transcription factor binding preferences are largely conserved between mammalian species. Based on this conservation, we hypothesized that enhancers active in different mammals would exhibit conserved sequence patterns in spite of their different genomic locations. To investigate this hypothesis, we evaluated the extent to which sequence patterns that are predictive of enhancers in one species are predictive of enhancers in other mammalian species by training and testing two types of machine learning models. We trained support vector machine (SVM) and convolutional neural network (CNN) classifiers to distinguish enhancers defined by histone marks from the genomic background based on DNA sequence patterns in human, macaque, mouse, dog, cow, and opossum. The classifiers accurately identified many adult liver, developing limb, and developing brain enhancers, and the CNNs outperformed the SVMs. Furthermore, classifiers trained in one species and tested in another performed nearly as well as classifiers trained and tested on the same species. We observed similar cross-species conservation when applying the models to human and mouse enhancers validated in transgenic assays. This indicates that many short sequence patterns predictive of enhancers are largely conserved. The sequence patterns most predictive of enhancers in each species matched the binding motifs for a common set of TFs enriched for expression in relevant tissues, supporting the biological relevance of the learned features. Thus, despite the rapid change of active enhancer locations between mammals, cross-species enhancer prediction is often possible. Our results suggest that short sequence patterns encoding enhancer activity have been maintained across more than 180 million years of mammalian evolution.
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Affiliation(s)
- Ling Chen
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States of America
| | - Alexandra E. Fish
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN, United States of America
| | - John A. Capra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States of America
- Vanderbilt Genetics Institute, Vanderbilt University, Nashville, TN, United States of America
- Departments of Biomedical Informatics and Computer Science, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States of America
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41
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Li B, Wu H, Guo H. Plant mRNA decay: extended roles and potential determinants. CURRENT OPINION IN PLANT BIOLOGY 2018; 45:178-184. [PMID: 30223189 DOI: 10.1016/j.pbi.2018.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 08/17/2018] [Accepted: 08/24/2018] [Indexed: 05/19/2023]
Abstract
The decay of mRNA in plants is tightly controlled and shapes the transcriptome. The roles of this process are to digest RNA as well as to suppress exogenous and endogenous gene silencing by preventing siRNA generation. Recent evidence suggests that mRNA decay also regulates the accumulation of the putative 3' fragment-derived long non-coding RNAs (3'lncRNAs). The generation of siRNA or 3'lncRNA from a selective subset of mRNAs raises a fundamental question of how the mRNA decay machineries select and determine their substrate transcripts for distinctive decay destiny. Evidence for potential mRNA decay determinants, such as codon bias, GC content and N6-methyladenosine (m6A) modification, is rapidly emerging. This paper aims to review the recent discoveries in plant mRNA decay.
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Affiliation(s)
- Bosheng Li
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Huihui Wu
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, China
| | - Hongwei Guo
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
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42
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Torrent M, Chalancon G, de Groot NS, Wuster A, Madan Babu M. Cells alter their tRNA abundance to selectively regulate protein synthesis during stress conditions. Sci Signal 2018; 11:11/546/eaat6409. [PMID: 30181241 PMCID: PMC6130803 DOI: 10.1126/scisignal.aat6409] [Citation(s) in RCA: 175] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Decoding the information in mRNA during protein synthesis relies on tRNA adaptors, the abundance of which can affect the decoding rate and translation efficiency. To determine whether cells alter tRNA abundance to selectively regulate protein expression, we quantified changes in the abundance of individual tRNAs at different time points in response to diverse stress conditions in Saccharomyces cerevisiae. We found that the tRNA pool was dynamic and rearranged in a manner that facilitated selective translation of stress-related transcripts. Through genomic analysis of multiple data sets, stochastic simulations, and experiments with designed sequences of proteins with identical amino acids but altered codon usage, we showed that changes in tRNA abundance affected protein expression independently of factors such as mRNA abundance. We suggest that cells alter their tRNA abundance to selectively affect the translation rates of specific transcripts to increase the amounts of required proteins under diverse stress conditions.
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Affiliation(s)
- Marc Torrent
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK. .,Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Guilhem Chalancon
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Natalia S de Groot
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Arthur Wuster
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - M Madan Babu
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK.
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43
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Mauro VP. Codon Optimization in the Production of Recombinant Biotherapeutics: Potential Risks and Considerations. BioDrugs 2018; 32:69-81. [PMID: 29392566 DOI: 10.1007/s40259-018-0261-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Biotherapeutics are increasingly becoming the mainstay in the treatment of a variety of human conditions, particularly in oncology and hematology. The production of therapeutic antibodies, cytokines, and fusion proteins have markedly accelerated these fields over the past decade and are probably the major contributor to improved patient outcomes. Today, most protein therapeutics are expressed as recombinant proteins in mammalian cell lines. An expression technology commonly used to increase protein levels involves codon optimization. This approach is possible because degeneracy of the genetic code enables most amino acids to be encoded by more than one synonymous codon and because codon usage can have a pronounced influence on levels of protein expression. Indeed, codon optimization has been reported to increase protein expression by > 1000-fold. The primary tactic of codon optimization is to increase the rate of translation elongation by overcoming limitations associated with species-specific differences in codon usage and transfer RNA (tRNA) abundance. However, in mammalian cells, assumptions underlying codon optimization appear to be poorly supported or unfounded. Moreover, because not all synonymous codon mutations are neutral, codon optimization can lead to alterations in protein conformation and function. This review discusses codon optimization for therapeutic protein production in mammalian cells.
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44
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Willis IM, Moir RD. Signaling to and from the RNA Polymerase III Transcription and Processing Machinery. Annu Rev Biochem 2018; 87:75-100. [PMID: 29328783 DOI: 10.1146/annurev-biochem-062917-012624] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA polymerase (Pol) III has a specialized role in transcribing the most abundant RNAs in eukaryotic cells, transfer RNAs (tRNAs), along with other ubiquitous small noncoding RNAs, many of which have functions related to the ribosome and protein synthesis. The high energetic cost of producing these RNAs and their central role in protein synthesis underlie the robust regulation of Pol III transcription in response to nutrients and stress by growth regulatory pathways. Downstream of Pol III, signaling impacts posttranscriptional processes affecting tRNA function in translation and tRNA cleavage into smaller fragments that are increasingly attributed with novel cellular activities. In this review, we consider how nutrients and stress control Pol III transcription via its factors and its negative regulator, Maf1. We highlight recent work showing that the composition of the tRNA population and the function of individual tRNAs is dynamically controlled and that unrestrained Pol III transcription can reprogram central metabolic pathways.
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Affiliation(s)
- Ian M Willis
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA; , .,Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA; ,
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45
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Mauro VP, Chappell SA. Considerations in the Use of Codon Optimization for Recombinant Protein Expression. Methods Mol Biol 2018; 1850:275-288. [PMID: 30242693 DOI: 10.1007/978-1-4939-8730-6_18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Codon optimization is a gene engineering approach that is commonly used for enhancing recombinant protein expression. This approach is possible because (1) degeneracy of the genetic code enables most amino acids to be encoded by multiple codons and (2) different mRNAs encoding the same protein can vary dramatically in the amount of protein expressed. However, because codon optimization potentially disrupts overlapping information encoded in mRNA coding regions, protein structure and function may be altered. This chapter discusses the use of codon optimization for various applications in mammalian cells as well as potential consequences, so that informed decisions can be made on the appropriateness of using this approach in each case.
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46
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Gajbhiye S, Patra P, Yadav MK. New insights into the factors affecting synonymous codon usage in human infecting Plasmodium species. Acta Trop 2017; 176:29-33. [PMID: 28751162 DOI: 10.1016/j.actatropica.2017.07.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/18/2017] [Accepted: 07/21/2017] [Indexed: 02/07/2023]
Abstract
Codon usage bias is due to the non-random usage of synonymous codons for coding amino acids. The synonymous sites are under weak selection, and codon usage bias is maintained by the equilibrium in mutational bias, genetic drift and selection pressure. The differential codon usage choices are also relevant to human infecting Plasmodium species. Recently, P. knowlesi switches its natural host, long-tailed macaques, and starts infecting humans. This review focuses on the comparative analysis of codon usage choices among human infecting P. falciparum and P. vivax along with P. knowlesi species taking their coding sequence data. The variation in GC content, amino acid frequencies, effective number of codons and other factors plays a crucial role in determining synonymous codon choices. Within species codon choices are more similar for P. vivax and P. knowlesi in comparison with P. falciparum species. This study suggests that synonymous codon choice modulates the gene expression level, mRNA stability, ribosome speed, protein folding, translation efficiency and its accuracy in Plasmodium species, and provides a valuable information regarding the codon usage pattern to facilitate gene cloning as well as expression and transfection studies for malaria causing species.
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47
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Kapur M, Monaghan CE, Ackerman SL. Regulation of mRNA Translation in Neurons-A Matter of Life and Death. Neuron 2017; 96:616-637. [PMID: 29096076 DOI: 10.1016/j.neuron.2017.09.057] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/20/2017] [Accepted: 09/28/2017] [Indexed: 12/14/2022]
Abstract
Dynamic regulation of mRNA translation initiation and elongation is essential for the survival and function of neural cells. Global reductions in translation initiation resulting from mutations in the translational machinery or inappropriate activation of the integrated stress response may contribute to pathogenesis in a subset of neurodegenerative disorders. Aberrant proteins generated by non-canonical translation initiation may be a factor in the neuron death observed in the nucleotide repeat expansion diseases. Dysfunction of central components of the elongation machinery, such as the tRNAs and their associated enzymes, can cause translational infidelity and ribosome stalling, resulting in neurodegeneration. Taken together, dysregulation of mRNA translation is emerging as a unifying mechanism underlying the pathogenesis of many neurodegenerative disorders.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Caitlin E Monaghan
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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48
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Zhao F, Yu CH, Liu Y. Codon usage regulates protein structure and function by affecting translation elongation speed in Drosophila cells. Nucleic Acids Res 2017; 45:8484-8492. [PMID: 28582582 PMCID: PMC5737824 DOI: 10.1093/nar/gkx501] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/26/2017] [Indexed: 11/14/2022] Open
Abstract
Codon usage biases are found in all eukaryotic and prokaryotic genomes and have been proposed to regulate different aspects of translation process. Codon optimality has been shown to regulate translation elongation speed in fungal systems, but its effect on translation elongation speed in animal systems is not clear. In this study, we used a Drosophila cell-free translation system to directly compare the velocity of mRNA translation elongation. Our results demonstrate that optimal synonymous codons speed up translation elongation while non-optimal codons slow down translation. In addition, codon usage regulates ribosome movement and stalling on mRNA during translation. Finally, we show that codon usage affects protein structure and function in vitro and in Drosophila cells. Together, these results suggest that the effect of codon usage on translation elongation speed is a conserved mechanism from fungi to animals that can affect protein folding in eukaryotic organisms.
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Affiliation(s)
- Fangzhou Zhao
- Department of Physiology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Chien-Hung Yu
- Department of Physiology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Yi Liu
- Department of Physiology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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49
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Marín M, Fernández-Calero T, Ehrlich R. Protein folding and tRNA biology. Biophys Rev 2017; 9:573-588. [PMID: 28944442 PMCID: PMC5662057 DOI: 10.1007/s12551-017-0322-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/28/2017] [Indexed: 12/14/2022] Open
Abstract
Polypeptides can fold into tertiary structures while they are synthesized by the ribosome. In addition to the amino acid sequence, protein folding is determined by several factors within the cell. Among others, the folding pathway of a nascent polypeptide can be affected by transient interactions with other proteins, ligands, or the ribosome, as well as by the translocation through membrane pores. Particularly, the translation machinery and the population of tRNA under different physiological or adaptive responses can dramatically affect protein folding. This review summarizes the scientific evidence describing the role of translation kinetics and tRNA populations on protein folding and addresses current efforts to better understand tRNA biology. It is organized into three main parts, which are focused on: (i) protein folding in the cellular context; (ii) tRNA biology and the complexity of the tRNA population; and (iii) available methods and technical challenges in the characterization of tRNA pools. In this manner, this work illustrates the ways by which functional properties of proteins may be modulated by cellular tRNA populations.
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Affiliation(s)
- Mónica Marín
- Biochemistry-Molecular Biology Section, Cellular and Molecular Biology Department, Faculty of Sciences, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
| | - Tamara Fernández-Calero
- Biochemistry-Molecular Biology Section, Cellular and Molecular Biology Department, Faculty of Sciences, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
- Bioinformatics Unit, Institut Pasteur Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay
| | - Ricardo Ehrlich
- Biochemistry-Molecular Biology Section, Cellular and Molecular Biology Department, Faculty of Sciences, Universidad de la República, Iguá 4225, 11400 Montevideo, Uruguay
- Institut Pasteur Montevideo, Mataojo 2020, 11400 Montevideo, Uruguay
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Van Bortle K, Phanstiel DH, Snyder MP. Topological organization and dynamic regulation of human tRNA genes during macrophage differentiation. Genome Biol 2017; 18:180. [PMID: 28931413 PMCID: PMC5607496 DOI: 10.1186/s13059-017-1310-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/25/2017] [Indexed: 12/11/2022] Open
Abstract
Background The human genome is hierarchically organized into local and long-range structures that help shape cell-type-specific transcription patterns. Transfer RNA (tRNA) genes (tDNAs), which are transcribed by RNA polymerase III (RNAPIII) and encode RNA molecules responsible for translation, are dispersed throughout the genome and, in many cases, linearly organized into genomic clusters with other tDNAs. Whether the location and three-dimensional organization of tDNAs contribute to the activity of these genes has remained difficult to address, due in part to unique challenges related to tRNA sequencing. We therefore devised integrated tDNA expression profiling, a method that combines RNAPIII mapping with biotin-capture of nascent tRNAs. We apply this method to the study of dynamic tRNA gene regulation during macrophage development and further integrate these data with high-resolution maps of 3D chromatin structure. Results Integrated tDNA expression profiling reveals domain-level and loop-based organization of tRNA gene transcription during cellular differentiation. tRNA genes connected by DNA loops, which are proximal to CTCF binding sites and expressed at elevated levels compared to non-loop tDNAs, change coordinately with tDNAs and protein-coding genes at distal ends of interactions mapped by in situ Hi-C. We find that downregulated tRNA genes are specifically marked by enhanced promoter-proximal binding of MAF1, a transcriptional repressor of RNAPIII activity, altogether revealing multiple levels of tDNA regulation during cellular differentiation. Conclusions We present evidence of both local and coordinated long-range regulation of human tDNA expression, suggesting the location and organization of tRNA genes contribute to dynamic tDNA activity during macrophage development. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1310-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kevin Van Bortle
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Douglas H Phanstiel
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA.,Thurston Arthritis Research Center and Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Michael P Snyder
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA.
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