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Demongeot J, Seligmann H. Evolution of small and large ribosomal RNAs from accretion of tRNA subelements. Biosystems 2022; 222:104796. [DOI: 10.1016/j.biosystems.2022.104796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/02/2022]
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2
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Demongeot J, Moreira A, Seligmann H. Negative CG dinucleotide bias: An explanation based on feedback loops between Arginine codon assignments and theoretical minimal RNA rings. Bioessays 2020; 43:e2000071. [PMID: 33319381 DOI: 10.1002/bies.202000071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 01/05/2023]
Abstract
Theoretical minimal RNA rings are candidate primordial genes evolved for non-redundant coding of the genetic code's 22 coding signals (one codon per biogenic amino acid, a start and a stop codon) over the shortest possible length: 29520 22-nucleotide-long RNA rings solve this min-max constraint. Numerous RNA ring properties are reminiscent of natural genes. Here we present analyses showing that all RNA rings lack dinucleotide CG (a mutable, chemically instable dinucleotide coding for Arginine), bearing a resemblance to known CG-depleted genomes. CG in "incomplete" RNA rings (not coding for all coding signals, with only 3-12 nucleotides) gradually decreases towards CG absence in complete, 22-nucleotide-long RNA rings. Presumably, feedback loops during RNA ring growth during evolution (when amino acid assignment fixed the genetic code) assigned Arg to codons lacking CG (AGR) to avoid CG. Hence, as a chemical property of base pairs, CG mutability restructured the genetic code, thereby establishing itself as genetically encoded biological information.
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Affiliation(s)
- Jacques Demongeot
- Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical & Labcom CNRS/UGA/OrangeLabs Telecom4Health, Faculty of Medicine, Université Grenoble Alpes, La Tronche, France
| | - Andrés Moreira
- Departamento de Informática, Universidad Técnica Federico Santa María, Santiago, Chile
| | - Hervé Seligmann
- Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical & Labcom CNRS/UGA/OrangeLabs Telecom4Health, Faculty of Medicine, Université Grenoble Alpes, La Tronche, France.,The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel.,Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany
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3
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Seligmann H, Warthi G. Natural pyrrolysine-biased translation of stop codons in mitochondrial peptides entirely coded by expanded codons. Biosystems 2020; 196:104180. [PMID: 32534170 DOI: 10.1016/j.biosystems.2020.104180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/02/2020] [Accepted: 06/02/2020] [Indexed: 12/31/2022]
Abstract
During the noncanonical deletion transcription, k nucleotides are systematically skipped/deleted after each transcribed trinucleotide producing deletion-RNAs (delRNAs). Peptides matching delRNAs either result from (a) canonical translation of delRNAs; or (b) noncanonical translation of regular transcripts along expanded codons. Only along frame "0" (start site) (a) and (b) produce identical peptides. Here, mitochondrial mass spectrometry data analyses assume expanded codon/del-transcription with 3 + k (k from 0 to 12) nucleotides. Detected peptides map preferentially on previously identified delRNAs. More peptides were detected for k (1-12) when del-transcriptional and expanded codon translations start sites coincide (i.e. the 0th frame) than for frames +1 or +2. Hence, both (a) and (b) produced peptides identified here. Biases for frame 0 decrease for k > 2, reflecting codon/anticodon expansion limits. Further analyses find preferential pyrrolysine insertion at stop codons, suggesting Pyl-specific mitochondrial suppressor tRNAs loaded by Pyl-specific tRNA synthetases with unknown origins. Pyl biases at stops are stronger for regular than expanded codons suggesting that Pyl-tRNAs are less competitive with near-cognate tRNAs in expanded codon contexts. Statistical biases for these findings exclude that detected peptides are experimental and/or bioinformatic artefacts implying both del-transcription and expanded codons translation occur in human mitochondria.
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Affiliation(s)
- Hervé Seligmann
- The National Natural History Collections, The Hebrew University of Jerusalem, 91404, Jerusalem, Israel; Université Grenoble Alpes, Faculty of Medicine, Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical, F-38700, La Tronche, France.
| | - Ganesh Warthi
- Aix-Marseille University, IRD, VITROME, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France.
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4
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Demongeot J, Seligmann H. Theoretical minimal RNA rings mimick molecular evolution before tRNA-mediated translation: codon-amino acid affinities increase from early to late RNA rings. C R Biol 2020; 343:111-122. [PMID: 32720493 DOI: 10.5802/crbiol.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 02/21/2020] [Indexed: 12/11/2022]
Abstract
Nucleotide affinities for noncovalent interactions with amino acids produce associations between mRNAs and cognate peptides, potentially regulating ribosomal translation. Correlations between nucleotide affinities and residue hydrophobicity are explored for 25 theoretical minimal RNA rings, 22 nucleotide-long RNAs designed in silico to code for each amino acid once after three translation rounds, and forming stem-loop hairpins. This design presumably mimicks life's first RNAs. RNA rings resemble consensual tRNAs, suggesting proto-tRNA function, predicted anticodon and cognate amino acid. The 25 RNA rings and their presumed evolutionary order, deduced from the genetic code integration order of the amino acid cognate to their predicted anticodon, produces noteworthy associations with several ancient properties of the cell's translational machinery. Here we use this system to explore the evolution of codon affinity-residue hydrophobicity correlations, assuming these reflect pre-tRNA and pre-ribosomal translations. This hypothesis expects that correlations decrease with genetic code inclusion orders of RNA ring cognates. RNA ring associations between nucleotide affinities and residue hydrophobicities resemble those from modern natural genes/proteins. Association strengths decrease with genetic code inclusion ranks of proto-tRNA cognate amino acids. In silico design of minimal RNA rings didn't account for affinities between RNA and peptides coded by these RNAs. Yet, interactions between RNA rings and translated cognate peptides resemble modern natural genes. This property is strongest for ancient RNA rings, weakest for recent RNA rings, spanning a period during which modern tRNA- and ribosome-based translation presumably evolved. Results indicate that translation lacking tRNA-like adaptors based on codon-amino acid affinities and the genetic code pre-existed tRNA-mediated translation. Theoretical minimal RNA rings appear valid prebiotic peptide-RNA world models for the transition between pre-tRNA- and tRNA-mediated translations.
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Affiliation(s)
- Jacques Demongeot
- Université Grenoble Alpes, Faculty of Medicine, Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical, F-38700 La Tronche, France
| | - Hervé Seligmann
- Université Grenoble Alpes, Faculty of Medicine, Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical, F-38700 La Tronche, France.,The National Natural History Collections, The Hebrew University of Jerusalem, 9190401 Jerusalem, Israel
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Demongeot J, Seligmann H. Deamination gradients within codons after 1<->2 position swap predict amino acid hydrophobicity and parallel β-sheet conformational preference. Biosystems 2020; 191-192:104116. [PMID: 32081715 DOI: 10.1016/j.biosystems.2020.104116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/04/2019] [Accepted: 02/10/2020] [Indexed: 12/16/2022]
Abstract
Deaminations C->T and A->G are frequent mutations producing nucleotide content gradients across genomes proportional to singlestrandedness during replication/transcription. Hence, within single codons, deamination risks increase from first to third codon positions, while second codon positions are functionally most crucial. Here genetic codes are analyzed assuming that after anticodons protected codons from deaminations, first and second codon positions swapped (N2N1N3->N1N2N3), with lowest deamination risks for N2 in presumed primitive N2N1N3 codons. N2N1N3, not standard N1N2N3, codon structure minimizes deaminations inversely proportionally to cognate amino acid hydrophobicity and parallel betasheet conformational preference. For N1N2N3, deamination minimization increases with genetic code integration order of cognate amino acids: during the presumed N2N1N3->N1N2N3 codon structure transition, protein synthesis combined direct codon-amino acid interactions for late amino acids and tRNA-based translation for early amino acids. Hence N2N1N3 codons would correspond to tRNA-free translation by spontaneous codon-amino acid affinities, and tRNA-mediated translation presumably caused N2N1N3->N1N2N3 swaps. Results show that rational, not arbitrary rules link codon and amino acid structures. Some analyses detect mitochondrial RNAs and peptides in public data corresponding to systematic position swaps, suggesting occasional swapping polymerase activity.
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Affiliation(s)
- Jacques Demongeot
- Université Grenoble Alpes, Faculty of Medicine, Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical, F-38700, La Tronche, France.
| | - Hervé Seligmann
- Université Grenoble Alpes, Faculty of Medicine, Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical, F-38700, La Tronche, France; The National Natural History Collections, The Hebrew University of Jerusalem, 91404, Jerusalem, Israel.
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Warthi G, Fournier PE, Seligmann H. Systematic Nucleotide Exchange Analysis of ESTs From the Human Cancer Genome Project Report: Origins of 347 Unknown ESTs Indicate Putative Transcription of Non-Coding Genomic Regions. Front Genet 2020; 11:42. [PMID: 32117454 PMCID: PMC7027195 DOI: 10.3389/fgene.2020.00042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 01/15/2020] [Indexed: 12/16/2022] Open
Abstract
Expressed sequence tags (ESTs) provide an imprint of cellular RNA diversity irrespectively of sequence homology with template genomes. NCBI databases include many unknown RNAs from various normal and cancer cells. These are usually ignored assuming sequencing artefacts or contamination due to their lack of sequence homology with template DNA. Here, we report genomic origins of 347 ESTs previously assumed artefacts/unknown, from the FAPESP/LICR Human Cancer Genome Project. EST template detection uses systematic nucleotide exchange analyses called swinger transformations. Systematic nucleotide exchanges replace systematically particular nucleotides with different nucleotides. Among 347 unknown ESTs, 51 ESTs match mitogenome transcription, 17 and 2 ESTs are from nuclear chromosome non-coding regions, and uncharacterized nuclear genes. Identified ESTs mapped on 205 protein-coding genes, 10 genes had swinger RNAs in several biosamples. Whole cell transcriptome searches for 17 ESTs mapping on non-coding regions confirmed their transcription. The 10 swinger-transcribed genes identified more than once associate with cancer induction and progression, suggesting swinger transformation occurs mainly in highly transcribed genes. Swinger transformation is a unique method to identify noncanonical RNAs obtained from NGS, which identifies putative ncRNA transcribed regions. Results suggest that swinger transcription occurs in highly active genes in normal and genetically unstable cancer cells.
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Affiliation(s)
- Ganesh Warthi
- Aix Marseille Univ, IRD, APHM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Pierre-Edouard Fournier
- Aix Marseille Univ, IRD, APHM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Hervé Seligmann
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel.,Université Grenoble Alpes, Faculty of Medicine, Laboratory AGEIS EA 7407, Team Tools for e-Gnosis Medical & Labcom CNRS/UGA/OrangeLabs Telecoms4Health, La Tronche, France
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7
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Li T, Yu L, Song B, Song Y, Li L, Lin X, Lin S. Genome Improvement and Core Gene Set Refinement of Fugacium kawagutii. Microorganisms 2020; 8:microorganisms8010102. [PMID: 31940756 PMCID: PMC7023079 DOI: 10.3390/microorganisms8010102] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 01/01/2020] [Accepted: 01/08/2020] [Indexed: 01/15/2023] Open
Abstract
Cataloging an accurate functional gene set for the Symbiodiniaceae species is crucial for addressing biological questions of dinoflagellate symbiosis with corals and other invertebrates. To improve the gene models of Fugacium kawagutii, we conducted high-throughput chromosome conformation capture (Hi-C) for the genome and Illumina combined with PacBio sequencing for the transcriptome to achieve a new genome assembly and gene prediction. A 0.937-Gbp assembly of F. kawagutii were obtained, with a N50 > 13 Mbp and the longest scaffold of 121 Mbp capped with telomere motif at both ends. Gene annotation produced 45,192 protein-coding genes, among which, 11,984 are new compared to previous versions of the genome. The newly identified genes are mainly enriched in 38 KEGG pathways including N-Glycan biosynthesis, mRNA surveillance pathway, cell cycle, autophagy, mitophagy, and fatty acid synthesis, which are important for symbiosis, nutrition, and reproduction. The newly identified genes also included those encoding O-methyltransferase (O-MT), 3-dehydroquinate synthase, homologous-pairing protein 2-like (HOP2) and meiosis protein 2 (MEI2), which function in mycosporine-like amino acids (MAAs) biosynthesis and sexual reproduction, respectively. The improved version of the gene set (Fugka_Geneset _V3) raised transcriptomic read mapping rate from 33% to 54% and BUSCO match from 29% to 55%. Further differential gene expression analysis yielded a set of stably expressed genes under variable trace metal conditions, of which 115 with annotated functions have recently been found to be stably expressed under three other conditions, thus further developing the "core gene set" of F. kawagutii. This improved genome will prove useful for future Symbiodiniaceae transcriptomic, gene structure, and gene expression studies, and the refined "core gene set" will be a valuable resource from which to develop reference genes for gene expression studies.
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Affiliation(s)
- Tangcheng Li
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; (T.L.); (L.Y.); (L.L.)
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
| | - Liying Yu
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; (T.L.); (L.Y.); (L.L.)
| | - Bo Song
- Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124, China;
| | - Yue Song
- BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China;
| | - Ling Li
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; (T.L.); (L.Y.); (L.L.)
| | - Xin Lin
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; (T.L.); (L.Y.); (L.L.)
- Correspondence: (X.L.); (S.L.)
| | - Senjie Lin
- State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China; (T.L.); (L.Y.); (L.L.)
- Department of Marine Sciences, University of Connecticut, Groton, CT 06340, USA
- Laboratory of Marine Biology and Biotechnology, Qingdao National Laboratory of Marine Science and Technology, Qingdao 266237, China
- Correspondence: (X.L.); (S.L.)
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The Uroboros Theory of Life's Origin: 22-Nucleotide Theoretical Minimal RNA Rings Reflect Evolution of Genetic Code and tRNA-rRNA Translation Machineries. Acta Biotheor 2019; 67:273-297. [PMID: 31388859 DOI: 10.1007/s10441-019-09356-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 07/31/2019] [Indexed: 02/06/2023]
Abstract
Theoretical minimal RNA rings attempt to mimick life's primitive RNAs. At most 25 22-nucleotide-long RNA rings code once for each biotic amino acid, a start and a stop codon and form a stem-loop hairpin, resembling consensus tRNAs. We calculated, for each RNA ring's 22 potential splicing positions, similarities of predicted secondary structures with tRNA vs. rRNA secondary structures. Assuming rRNAs partly derived from tRNA accretions, we predict positive associations between relative secondary structure similarities with rRNAs over tRNAs and genetic code integration orders of RNA ring anticodon cognate amino acids. Analyses consider for each secondary structure all nucleotide triplets as potential anticodon. Anticodons for ancient, chemically inert cognate amino acids are most frequent in the 25 RNA rings. For RNA rings with primordial cognate amino acids according to tRNA-homology-derived anticodons, tRNA-homology and coding sequences coincide, these are separate for predicted cognate amino acids that presumably integrated late the genetic code. RNA ring secondary structure similarity with rRNA over tRNA secondary structures associates best with genetic code integration orders of anticodon cognate amino acids when assuming split anticodons (one and two nucleotides at the spliced RNA ring 5' and 3' extremities, respectively), and at predicted anticodon location in the spliced RNA ring's midst. Results confirm RNA ring homologies with tRNAs and CDs, ancestral status of tRNA half genes split at anticodons, the tRNA-rRNA axis of RNA evolution, and that single theoretical minimal RNA rings potentially produce near-complete proto-tRNA sets. Hence genetic code pre-existence determines 25 short circular gene- and tRNA-like RNAs. Accounting for each potential splicing position, each RNA ring potentially translates most amino acids, realistically mimicks evolution of the tRNA-rRNA translation machinery. These RNA rings 'of creation' remind the uroboros' (snake biting its tail) symbolism for creative regeneration.
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10
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Seligmann H. Syntenies Between Cohosted Mitochondrial, Chloroplast, and Phycodnavirus Genomes: Functional Mimicry and/or Common Ancestry? DNA Cell Biol 2019; 38:1257-1268. [DOI: 10.1089/dna.2019.4858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Hervé Seligmann
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
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Seligmann H, Warthi G. Chimeric Translation for Mitochondrial Peptides: Regular and Expanded Codons. Comput Struct Biotechnol J 2019; 17:1195-1202. [PMID: 31534643 PMCID: PMC6742854 DOI: 10.1016/j.csbj.2019.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/19/2019] [Accepted: 08/21/2019] [Indexed: 02/07/2023] Open
Abstract
Frameshifting protein translation occasionally results from insertion of amino acids at isolated mono- or dinucleotide-expanded codons by tRNAs with expanded anticodons. Previous analyses of two different types of human mitochondrial MS proteomic data (Fisher and Waters technologies) detect peptides entirely corresponding to expanded codon translation. Here, these proteomic data are reanalyzed searching for peptides consisting of at least eight consecutive amino acids translated according to regular tricodons, and at least eight adjacent consecutive amino acids translated according to expanded codons. Both datasets include chimerically translated peptides (mono- and dinucleotide expansions, 42 and 37, respectively). The regular tricodon-encoded part of some chimeric peptides corresponds to standard human mitochondrial proteins (mono- and dinucleotide expansions, six (AT6, CytB, ND1, 2xND2, ND5) and one (ND1), respectively). Chimeric translation probably increases the diversity of mitogenome-encoded proteins, putatively producing functional proteins. These might result from translation by tRNAs with expanded anticodons, or from regular tricodon translation of RNAs where transcription/posttranscriptional edition systematically deleted mono- or dinucleotides after each trinucleotide. The pairwise matched combination of adjacent peptide parts translated from regular and expanded codons strengthens the hypothesis that translation of stretches of consecutive expanded codons occurs. Results indicate statistical translation producing distributions of alternative proteins. Genetic engineering should account for potential unexpected, unwanted secondary products.
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Affiliation(s)
- Hervé Seligmann
- The National Natural History Collections, The Hebrew University of Jerusalem, 91404 Jerusalem, Israel
| | - Ganesh Warthi
- Aix-Marseille University, IRD, VITROME, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
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Demongeot J, Seligmann H. Theoretical minimal RNA rings designed according to coding constraints mimic deamination gradients. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2019; 106:44. [DOI: 10.1007/s00114-019-1638-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 11/27/2022]
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Warthi G, Seligmann H. Transcripts with systematic nucleotide deletion of 1-12 nucleotide in human mitochondrion suggest potential non-canonical transcription. PLoS One 2019; 14:e0217356. [PMID: 31120958 PMCID: PMC6532905 DOI: 10.1371/journal.pone.0217356] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/09/2019] [Indexed: 11/22/2022] Open
Abstract
Raw transcriptomic data contain numerous RNA reads whose homology with template DNA doesn't match canonical transcription. Transcriptome analyses usually ignore such noncanonical RNA reads. Here, analyses search for noncanonical mitochondrial RNAs systematically deleting 1 to 12 nucleotides after each transcribed nucleotide triplet, producing deletion-RNAs (delRNAs). We detected delRNAs in the human whole cell and purified mitochondrial transcriptomes, and in Genbank's human EST database corresponding to systematic deletions of 1 to 12 nucleotides after each transcribed trinucleotide. DelRNAs detected in both transcriptomes mapped along with 55.63% of the EST delRNAs. A bias exists for delRNAs covering identical mitogenomic regions in both transcriptomic and EST datasets. Among 227 delRNAs detected in these 3 datasets, 81.1% and 8.4% of delRNAs were mapped on mitochondrial coding and hypervariable region 2 of dloop. Del-transcription analyses of GenBank's EST database confirm observations from whole cell and purified mitochondrial transcriptomes, eliminating the possibility that detected delRNAs are false positives matches, cytosolic DNA/RNA nuclear contamination or sequencing artefacts. These detected delRNAs are enriched in frameshift-inducing homopolymers and are poor in frameshift-preventing circular code codons (a set of 20 codons which regulate reading frame detection, over- and underrepresented in coding and other frames of genes, respectively) suggesting a motif-based regulation of non-canonical transcription. These findings show that rare non-canonical transcripts exist. Such non canonical del-transcription does increases mitochondrial coding potential and non-coding regulation of intracellular mechanisms, and could explain the dark DNA conundrum.
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Affiliation(s)
- Ganesh Warthi
- Aix-Marseille Université, IRD, VITROME, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Hervé Seligmann
- Aix-Marseille Université, IRD, MEPHI, Institut Hospitalo-Universitaire (IHU) Méditerranée Infection, Marseille, France
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
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Guyomar C, Gillet R. When transfer-messenger RNA scars reveal its ancient origins. Ann N Y Acad Sci 2019; 1447:80-87. [PMID: 30815901 DOI: 10.1111/nyas.14035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/23/2019] [Accepted: 01/30/2019] [Indexed: 12/12/2022]
Abstract
In bacteria, trans-translation is the primary quality control mechanism for rescuing ribosomes arrested during translation. This key process is universally conserved and plays a crucial role in the viability and virulence of all bacteria. It is performed by transfer-messenger RNA (tmRNA) and its protein partner small protein B (SmpB). Here, we show that tmRNA is a key molecule that could have given birth to modern protein synthesis. The traces of an ancient RNA world persist in the structure of modern tmRNA, suggesting its old origins. Therefore, since it has both tRNA and mRNA functions, tmRNA could be the missing link that allowed modern genetic code to be read by the ribosome.
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Affiliation(s)
- Charlotte Guyomar
- Université de Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Rennes, France
| | - Reynald Gillet
- Université de Rennes, CNRS, IGDR (Institut de génétique et développement de Rennes) - UMR 6290, F-35000, Rennes, France
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Abstract
INTRODUCTION Small open reading frames (sORFs) with potential protein-coding capacity have been disclosed in various transcripts, including long noncoding RNAs (LncRNAs), mRNAs (5'-upstream, coding domain, and 3'-downstream), circular RNAs, pri-miRNAs, and ribosomal RNAs (rRNAs). Recent characterization of several sORF-encoded peptides (SEPs or micropeptides) revealed their important roles in many fundamental biological processes in a broad range of species from yeast to human. The success in the mining of micropeptides attributes to the advanced bioinformatics and high-throughput sequencing techniques. Areas covered: sORFs and SEPs were overlooked for their tiny size and the difficulty of identification by bioinformatics analyses. With more and more sORFs and SEPs have been identified, this field has attracted more attention. This review covers recent advances in the strategies for the detection and identification of sORFs and SEPs. Expert commentary: The advantages and drawbacks of the strategies for detection and identification of sORFs and SEPs are discussed, as well as the techniques that are used to decipher the roles of micropeptides in organisms are described.
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Affiliation(s)
- Xinqiang Yin
- a The Engineering Research Center of Synthetic Polypeptide Drug Discovery and Evaluation of Jiangsu Province , China Pharmaceutical University , Nanjing , China.,b The Basic Medical School , North Sichuan Medical College , Nanchong , China
| | - Yuanyuan Jing
- c Department of Preventive Medicine , North Sichuan Medical College , Nanchong , China
| | - Hanmei Xu
- a The Engineering Research Center of Synthetic Polypeptide Drug Discovery and Evaluation of Jiangsu Province , China Pharmaceutical University , Nanjing , China.,d State Key Laboratory of Natural Medicines, Ministry of Education , China Pharmaceutical University , Nanjing , China
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16
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Single-Frame, Multiple-Frame and Framing Motifs in Genes. Life (Basel) 2019; 9:life9010018. [PMID: 30744207 PMCID: PMC6463195 DOI: 10.3390/life9010018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/24/2019] [Accepted: 01/31/2019] [Indexed: 12/12/2022] Open
Abstract
We study the distribution of new classes of motifs in genes, a research field that has not been investigated to date. A single-frame motif SF has no trinucleotide in reading frame (frame 0) that occurs in a shifted frame (frame 1 or 2), e.g., the dicodon AAACAA is SF as the trinucleotides AAA and CAA do not occur in a shifted frame. A motif which is not single-frame SF is multiple-frame MF. Several classes of MF motifs are defined and analysed. The distributions of single-frame SF motifs (associated with an unambiguous trinucleotide decoding in the two 5′–3′ and 3′–5′ directions) and 5′ unambiguous motifs 5′U (associated with an unambiguous trinucleotide decoding in the 5′–3′ direction only) are analysed without and with constraints. The constraints studied are: initiation and stop codons, periodic codons {AAA,CCC,GGG,TTT}, antiparallel complementarity and parallel complementarity. Taken together, these results suggest that the complementarity property involved in the antiparallel (DNA double helix, RNA stem) and parallel sequences could also be fundamental for coding genes with an unambiguous trinucleotide decoding in the two 5′–3′ and 3′–5′ directions or the 5′–3′ direction only. Furthermore, the single-frame motifs SF with a property of trinucleotide decoding and the framing motifs F (also called circular code motifs; first introduced by Michel (2012)) with a property of reading frame decoding may have been involved in the early life genes to build the modern genetic code and the extant genes. They could have been involved in the stage without anticodon-amino acid interactions or in the Implicated Site Nucleotides (ISN) of RNA interacting with the amino acids. Finally, the SF and MF dipeptides associated with the SF and MF dicodons, respectively, are studied and their importance for biology and the origin of life discussed.
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Dila G, Michel CJ, Poch O, Ripp R, Thompson JD. Evolutionary conservation and functional implications of circular code motifs in eukaryotic genomes. Biosystems 2019; 175:57-74. [DOI: 10.1016/j.biosystems.2018.10.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 10/08/2018] [Accepted: 10/17/2018] [Indexed: 12/13/2022]
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Seligmann H. Protein Sequences Recapitulate Genetic Code Evolution. Comput Struct Biotechnol J 2018; 16:177-189. [PMID: 30002789 PMCID: PMC6040577 DOI: 10.1016/j.csbj.2018.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/14/2018] [Accepted: 05/17/2018] [Indexed: 12/16/2022] Open
Abstract
Several hypotheses predict ranks of amino acid assignments to genetic code's codons. Analyses here show that average positions of amino acid species in proteins correspond to assignment ranks, in particular as predicted by Juke's neutral mutation hypothesis for codon assignments. In all tested protein groups, including co- and post-translationally folding proteins, 'recent' amino acids are on average closer to gene 5' extremities than 'ancient' ones. Analyses of pairwise residue contact energies matrices suggest that early amino acids stereochemically selected late ones that stablilize residue interactions within protein cores, presumably producing 5'-late-to-3'-early amino acid protein sequence gradients. The gradient might reduce protein misfolding, also after mutations, extending principles of neutral mutations to protein folding. Presumably, in self-perpetuating and self-correcting systems like the genetic code, initial conditions produce similarities between evolution of the process (the genetic code) and 'ontogeny' of resulting structures (here proteins), producing apparent teleonomy between process and product.
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Affiliation(s)
- Hervé Seligmann
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR MEPHI, Aix-Marseille Université, IRD, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, 19-21 boulevard Jean Moulin, 13005 Marseille, France.
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Alignment-based and alignment-free methods converge with experimental data on amino acids coded by stop codons at split between nuclear and mitochondrial genetic codes. Biosystems 2018; 167:33-46. [DOI: 10.1016/j.biosystems.2018.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 12/11/2022]
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20
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Seligmann H, Raoult D. Stem-Loop RNA Hairpins in Giant Viruses: Invading rRNA-Like Repeats and a Template Free RNA. Front Microbiol 2018; 9:101. [PMID: 29449833 PMCID: PMC5799277 DOI: 10.3389/fmicb.2018.00101] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 01/16/2018] [Indexed: 12/31/2022] Open
Abstract
We examine the hypothesis that de novo template-free RNAs still form spontaneously, as they did at the origins of life, invade modern genomes, contribute new genetic material. Previously, analyses of RNA secondary structures suggested that some RNAs resembling ancestral (t)RNAs formed recently de novo, other parasitic sequences cluster with rRNAs. Here positive control analyses of additional RNA secondary structures confirm ancestral and de novo statuses of RNA grouped according to secondary structure. Viroids with branched stems resemble de novo RNAs, rod-shaped viroids resemble rRNA secondary structures, independently of GC contents. 5' UTR leading regions of West Nile and Dengue flavivirid viruses resemble de novo and rRNA structures, respectively. An RNA homologous with Megavirus, Dengue and West Nile genomes, copperhead snake microsatellites and levant cotton repeats, not templated by Mimivirus' genome, persists throughout Mimivirus' infection. Its secondary structure clusters with candidate de novo RNAs. The saltatory phyletic distribution and secondary structure of Mimivirus' peculiar RNA suggest occasional template-free polymerization of this sequence, rather than noncanonical transcriptions (swinger polymerization, posttranscriptional editing).
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Affiliation(s)
- Hervé Seligmann
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR MEPHI, Aix-Marseille Université, IRD, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
| | - Didier Raoult
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR MEPHI, Aix-Marseille Université, IRD, Assistance Publique-Hôpitaux de Marseille, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, France
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21
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Mathematical fundamentals for the noise immunity of the genetic code. Biosystems 2018; 164:186-198. [DOI: 10.1016/j.biosystems.2017.09.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/07/2017] [Accepted: 09/08/2017] [Indexed: 01/05/2023]
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22
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Bijective codon transformations show genetic code symmetries centered on cytosine's coding properties. Theory Biosci 2017; 137:17-31. [PMID: 29147851 DOI: 10.1007/s12064-017-0258-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/13/2017] [Indexed: 12/11/2022]
Abstract
Homology of some RNAs with template DNA requires systematic exchanges between nucleotides. Such exchanges produce 'swinger' RNA along 23 bijective transformations (nine symmetric, X ↔ Y; and 14 asymmetric, X → Y → Z → X, for example A ↔ C and A → C → G → A, respectively). Here, analyses compare amino acids coded by swinger-transformed codons to those coded by untransformed codons, defining coding invariance after transformations. Swinger transformations cluster according to coding invariance in four groups characterized by transformations into cytosine (C = C, T → C, A → C, and G → C). C's central mutational coding role shows that swinger transformations constrained genetic code genesis. Coding invariance post-transformations correlate positively/negatively with mitochondrial swinger transcription/lepidosaurian body temperature. Presumably, low/high temperatures stabilize/revert rare swinger polymerization modes, producing long swinger sequences/point mutations, respectively. Coding invariance after swinger transformations might compensate effects of swinger polymerizations in species with low body temperatures. Hypothetically, swinger transcription increased coding potential of RNA self-replicating protolife systems under heating/cooling cycles.
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Seligmann H, Warthi G. Genetic Code Optimization for Cotranslational Protein Folding: Codon Directional Asymmetry Correlates with Antiparallel Betasheets, tRNA Synthetase Classes. Comput Struct Biotechnol J 2017; 15:412-424. [PMID: 28924459 PMCID: PMC5591391 DOI: 10.1016/j.csbj.2017.08.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/20/2017] [Accepted: 08/05/2017] [Indexed: 12/14/2022] Open
Abstract
A new codon property, codon directional asymmetry in nucleotide content (CDA), reveals a biologically meaningful genetic code dimension: palindromic codons (first and last nucleotides identical, codon structure XZX) are symmetric (CDA = 0), codons with structures ZXX/XXZ are 5'/3' asymmetric (CDA = - 1/1; CDA = - 0.5/0.5 if Z and X are both purines or both pyrimidines, assigning negative/positive (-/+) signs is an arbitrary convention). Negative/positive CDAs associate with (a) Fujimoto's tetrahedral codon stereo-table; (b) tRNA synthetase class I/II (aminoacylate the 2'/3' hydroxyl group of the tRNA's last ribose, respectively); and (c) high/low antiparallel (not parallel) betasheet conformation parameters. Preliminary results suggest CDA-whole organism associations (body temperature, developmental stability, lifespan). Presumably, CDA impacts spatial kinetics of codon-anticodon interactions, affecting cotranslational protein folding. Some synonymous codons have opposite CDA sign (alanine, leucine, serine, and valine), putatively explaining how synonymous mutations sometimes affect protein function. Correlations between CDA and tRNA synthetase classes are weaker than between CDA and antiparallel betasheet conformation parameters. This effect is stronger for mitochondrial genetic codes, and potentially drives mitochondrial codon-amino acid reassignments. CDA reveals information ruling nucleotide-protein relations embedded in reversed (not reverse-complement) sequences (5'-ZXX-3'/5'-XXZ-3').
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Affiliation(s)
- Hervé Seligmann
- Aix-Marseille Univ, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS UMR7278, IRD 198, INSERM U1095, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, Postal code 13385, France
- Dept. Ecol Evol Behav, Alexander Silberman Inst Life Sci, The Hebrew University of Jerusalem, IL-91904 Jerusalem, Israel
| | - Ganesh Warthi
- Aix-Marseille Univ, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM 63, CNRS UMR7278, IRD 198, INSERM U1095, Institut Hospitalo-Universitaire Méditerranée-Infection, Marseille, Postal code 13385, France
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