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Karki P, Carney TD, Maracci C, Yatsenko AS, Shcherbata HR, Rodnina MV. Tissue-specific regulation of translational readthrough tunes functions of the traffic jam transcription factor. Nucleic Acids Res 2021; 50:6001-6019. [PMID: 34897510 PMCID: PMC9226519 DOI: 10.1093/nar/gkab1189] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/05/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Translational readthrough (TR) occurs when the ribosome decodes a stop codon as a sense codon, resulting in two protein isoforms synthesized from the same mRNA. TR has been identified in several eukaryotic organisms; however, its biological significance and mechanism remain unclear. Here, we quantify TR of several candidate genes in Drosophila melanogaster and characterize the regulation of TR in the large Maf transcription factor Traffic jam (Tj). Using CRISPR/Cas9-generated mutant flies, we show that the TR-generated Tj isoform is expressed in a subset of neural cells of the central nervous system and is excluded from the somatic cells of gonads. Control of TR in Tj is critical for preservation of neuronal integrity and maintenance of reproductive health. The tissue-specific distribution of a release factor splice variant, eRF1H, plays a critical role in modulating differential TR of leaky stop codon contexts. Fine-tuning of gene regulatory functions of transcription factors by TR provides a potential mechanism for cell-specific regulation of gene expression.
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Affiliation(s)
- Prajwal Karki
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
| | - Travis D Carney
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Cristina Maracci
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
| | - Andriy S Yatsenko
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Halyna R Shcherbata
- Gene Expression and Signaling Group, Institute of Cell Biochemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany
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Massey SE. The identities of stop codon reassignments support ancestral tRNA stop codon decoding activity as a facilitator of gene duplication and evolution of novel function. Gene 2017; 619:37-43. [DOI: 10.1016/j.gene.2017.03.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Revised: 03/20/2017] [Accepted: 03/25/2017] [Indexed: 10/19/2022]
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Nyikó T, Auber A, Szabadkai L, Benkovics A, Auth M, Mérai Z, Kerényi Z, Dinnyés A, Nagy F, Silhavy D. Expression of the eRF1 translation termination factor is controlled by an autoregulatory circuit involving readthrough and nonsense-mediated decay in plants. Nucleic Acids Res 2017; 45:4174-4188. [PMID: 28062855 PMCID: PMC5397192 DOI: 10.1093/nar/gkw1303] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/24/2016] [Accepted: 12/28/2016] [Indexed: 12/28/2022] Open
Abstract
When a ribosome reaches a stop codon, the eukaryotic Release Factor 1 (eRF1) binds to the A site of the ribosome and terminates translation. In yeasts and plants, both over- and underexpression of eRF1 lead to altered phenotype indicating that eRF1 expression should be strictly controlled. However, regulation of eRF1 level is still poorly understood. Here we show that expression of plant eRF1 is controlled by a complex negative autoregulatory circuit, which is based on the unique features of the 3΄untranslated region (3΄UTR) of the eRF1-1 transcript. The stop codon of the eRF1-1 mRNA is in a translational readthrough promoting context, while its 3΄UTR induces nonsense-mediated decay (NMD), a translation termination coupled mRNA degradation mechanism. We demonstrate that readthrough partially protects the eRF1-1 mRNA from its 3΄UTR induced NMD, and that elevated eRF1 levels inhibit readthrough and stimulate NMD. Thus, high eRF1 level leads to reduced eRF1-1 expression, as weakened readthrough fails to protect the eRF1-1 mRNA from the more intense NMD. This eRF1 autoregulatory circuit might serve to finely balance general translation termination efficiency.
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Affiliation(s)
- Tünde Nyikó
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Andor Auber
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Levente Szabadkai
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Anna Benkovics
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Mariann Auth
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Zsuzsanna Mérai
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Zoltán Kerényi
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Andrea Dinnyés
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
| | - Ferenc Nagy
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Temesvári 62, H-6726, Hungary
| | - Dániel Silhavy
- Department of Genetics, Agricultural Biotechnology Institute, Gödöllő, Szent-Györgyi 4, H-2100, Hungary
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4
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Edwards MC, Weiland JJ. Coat protein expression strategy of oat blue dwarf virus. Virology 2014; 450-451:290-6. [PMID: 24503092 PMCID: PMC7173039 DOI: 10.1016/j.virol.2013.12.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/19/2013] [Accepted: 12/15/2013] [Indexed: 02/03/2023]
Abstract
Oat blue dwarf virus (OBDV) is a member of the genus Marafivirus whose genome encodes a 227 kDa polyprotein (p227) ostensibly processed post-translationally into its functional components. Encoded near the 3' terminus and coterminal with the p227 ORF are ORFs specifying major and minor capsid proteins (CP). Since the CP expression strategy of marafiviruses has not been thoroughly investigated, we produced a series of point mutants in the OBDV CP encoding gene and examined expression in protoplasts. Results support a model in which the 21 kDa major CP is the product of direct translation of a sgRNA, while the 24 kDa minor CP is a cleavage product derived from both the polyprotein and a larger ~26 kDa precursor translated directly from the sgRNA. Cleavage occurs at an LXG[G/A] motif conserved in many viruses that use papain-like proteases for polyprotein processing and protection against degradation via the ubiquitin-proteasome system.
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Affiliation(s)
- Michael C Edwards
- USDA-Agricultural Research Service, Cereal Crops Research Unit, Northern Crop Science Laboratory, 1605 Albrecht Blvd. N., Fargo, ND 58102-2765, USA.
| | - John J Weiland
- USDA-Agricultural Research Service, Cereal Crops Research Unit, Northern Crop Science Laboratory, 1605 Albrecht Blvd. N., Fargo, ND 58102-2765, USA
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5
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Unassigned codons, nonsense suppression, and anticodon modifications in the evolution of the genetic code. J Mol Evol 2011; 73:59-69. [PMID: 22076654 DOI: 10.1007/s00239-011-9470-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 10/24/2011] [Indexed: 10/15/2022]
Abstract
The origin of the genetic code is a central open problem regarding the early evolution of life. Here, we consider two undeveloped but important aspects of possible scenarios for the evolutionary pathway of the translation machinery: the role of unassigned codons in early stages of the code and the incorporation of tRNA anticodon modifications. As the first codons started to encode amino acids, the translation machinery likely was faced with a large number of unassigned codons. Current molecular scenarios for the evolution of the code usually assume the very rapid assignment of all codons before all 20 amino acids became encoded. We show that the phenomenon of nonsense suppression as observed in current organisms allows for a scenario in which many unassigned codons persisted throughout most of the evolutionary development of the code. In addition, we demonstrate that incorporation of anticodon modifications at a late stage is feasible. The wobble rules allow a set of 20 tRNAs fully lacking anticodon modifications to encode all 20 canonical amino acids. These observations have implications for the biochemical plausibility of early stages in the evolution of the genetic code predating tRNA anticodon modifications and allow for effective translation by a relatively small and simple early tRNA set.
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Jungreis I, Lin MF, Spokony R, Chan CS, Negre N, Victorsen A, White KP, Kellis M. Evidence of abundant stop codon readthrough in Drosophila and other metazoa. Genome Res 2011; 21:2096-113. [PMID: 21994247 DOI: 10.1101/gr.119974.110] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
While translational stop codon readthrough is often used by viral genomes, it has been observed for only a handful of eukaryotic genes. We previously used comparative genomics evidence to recognize protein-coding regions in 12 species of Drosophila and showed that for 149 genes, the open reading frame following the stop codon has a protein-coding conservation signature, hinting that stop codon readthrough might be common in Drosophila. We return to this observation armed with deep RNA sequence data from the modENCODE project, an improved higher-resolution comparative genomics metric for detecting protein-coding regions, comparative sequence information from additional species, and directed experimental evidence. We report an expanded set of 283 readthrough candidates, including 16 double-readthrough candidates; these were manually curated to rule out alternatives such as A-to-I editing, alternative splicing, dicistronic translation, and selenocysteine incorporation. We report experimental evidence of translation using GFP tagging and mass spectrometry for several readthrough regions. We find that the set of readthrough candidates differs from other genes in length, composition, conservation, stop codon context, and in some cases, conserved stem-loops, providing clues about readthrough regulation and potential mechanisms. Lastly, we expand our studies beyond Drosophila and find evidence of abundant readthrough in several other insect species and one crustacean, and several readthrough candidates in nematode and human, suggesting that functionally important translational stop codon readthrough is significantly more prevalent in Metazoa than previously recognized.
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Affiliation(s)
- Irwin Jungreis
- MIT Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Kochetov AV, Volkova OA, Poliakov A, Dubchak I, Rogozin IB. Tandem termination signal in plant mRNAs. Gene 2011; 481:1-6. [PMID: 21539902 DOI: 10.1016/j.gene.2011.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 02/17/2011] [Accepted: 04/15/2011] [Indexed: 12/12/2022]
Abstract
It was proposed that if some mRNA characteristics resulted in a low efficiency of termination signal, an additional closely located stop codon (tandem stop codons) could be used to prevent the harmful readthrough. However, the role of tandem terminators in higher eukaryotes was not verified and remains hypothetical. In this work the sequence features of Arabidopsis thaliana and Oryza sativa mRNAs were analyzed. It was found that plant mRNAs with UGA terminator were characterized by a higher frequency of nonsense codons in the first triplet position of 3'-UTR that could result from a weak natural selection for "reserve" stop signal. Interestingly, the presence of tandem stop codons positively correlated with a specific amino acid composition in the C-terminal position of the encoded proteins. In particular, C-terminal glycine positively correlated with significantly higher frequencies of reserve terminators at the beginning positions of 3'-UTR in UGA-containing mRNAs. This finding coincides with some earlier observations concerning the role of glycine and its codons in inefficient termination of translation and recoding (e.g., 2A oligopeptide).
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Affiliation(s)
- Alex V Kochetov
- Institute of Cytology and Genetics, Lavrentieva ave. 10, Novosibirsk, 630090, Russia.
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