1
|
Salman A, Biziaev N, Shuvalova E, Alkalaeva E. mRNA context and translation factors determine decoding in alternative nuclear genetic codes. Bioessays 2024; 46:e2400058. [PMID: 38724251 DOI: 10.1002/bies.202400058] [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: 03/14/2024] [Revised: 04/19/2024] [Accepted: 04/23/2024] [Indexed: 06/27/2024]
Abstract
The genetic code is a set of instructions that determine how the information in our genetic material is translated into amino acids. In general, it is universal for all organisms, from viruses and bacteria to humans. However, in the last few decades, exceptions to this rule have been identified both in pro- and eukaryotes. In this review, we discuss the 16 described alternative eukaryotic nuclear genetic codes and observe theories of their appearance in evolution. We consider possible molecular mechanisms that allow codon reassignment. Most reassignments in nuclear genetic codes are observed for stop codons. Moreover, in several organisms, stop codons can simultaneously encode amino acids and serve as termination signals. In this case, the meaning of the codon is determined by the additional factors besides the triplets. A comprehensive review of various non-standard coding events in the nuclear genomes provides a new insight into the translation mechanism in eukaryotes.
Collapse
Affiliation(s)
- Ali Salman
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Nikita Biziaev
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Ekaterina Shuvalova
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| | - Elena Alkalaeva
- Engelhardt Institute of Molecular Biology, the Russian Academy of Sciences, Moscow, Russia
| |
Collapse
|
2
|
Zavala B, Dineen L, Fisher KJ, Opulente DA, Harrison MC, Wolters JF, Shen XX, Zhou X, Groenewald M, Hittinger CT, Rokas A, LaBella AL. Genomic factors shaping codon usage across the Saccharomycotina subphylum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.23.595506. [PMID: 38826271 PMCID: PMC11142207 DOI: 10.1101/2024.05.23.595506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
Codon usage bias, or the unequal use of synonymous codons, is observed across genes, genomes, and between species. The biased use of synonymous codons has been implicated in many cellular functions, such as translation dynamics and transcript stability, but can also be shaped by neutral forces. The Saccharomycotina, the fungal subphylum containing the yeasts Saccharomyces cerevisiae and Candida albicans , has been a model system for studying codon usage. We characterized codon usage across 1,154 strains from 1,051 species to gain insight into the biases, molecular mechanisms, evolution, and genomic features contributing to codon usage patterns across the subphylum. We found evidence of a general preference for A/T-ending codons and correlations between codon usage bias, GC content, and tRNA-ome size. Codon usage bias is also distinct between the 12 orders within the subphylum to such a degree that yeasts can be classified into orders with an accuracy greater than 90% using a machine learning algorithm trained on codon usage. We also characterized the degree to which codon usage bias is impacted by translational selection. Interestingly, the degree of translational selection was influenced by a combination of genome features and assembly metrics that included the number of coding sequences, BUSCO count, and genome length. Our analysis also revealed an extreme bias in codon usage in the Saccharomycodales associated with a lack of predicted arginine tRNAs. The order contains 24 species, and 23 are computationally predicted to lack tRNAs that decode CGN codons, leaving only the AGN codons to encode arginine. Analysis of Saccharomycodales gene expression, tRNA sequences, and codon evolution suggests that extreme avoidance of the CGN codons is associated with a decline in arginine tRNA function. Codon usage bias within the Saccharomycotina is generally consistent with previous investigations in fungi, which show a role for both genomic features and GC bias in shaping codon usage. However, we find cases of extreme codon usage preference and avoidance along yeast lineages, suggesting additional forces may be shaping the evolution of specific codons.
Collapse
|
3
|
Sanchez-Puerta MV, Ceriotti LF, Gatica-Soria LM, Roulet ME, Garcia LE, Sato HA. Invited Review Beyond parasitic convergence: unravelling the evolution of the organellar genomes in holoparasites. ANNALS OF BOTANY 2023; 132:909-928. [PMID: 37503831 PMCID: PMC10808021 DOI: 10.1093/aob/mcad108] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/27/2023] [Indexed: 07/29/2023]
Abstract
BACKGROUND The molecular evolution of organellar genomes in angiosperms has been studied extensively, with some lineages, such as parasitic ones, displaying unique characteristics. Parasitism has emerged 12 times independently in angiosperm evolution. Holoparasitism is the most severe form of parasitism, and is found in ~10 % of parasitic angiosperms. Although a few holoparasitic species have been examined at the molecular level, most reports involve plastomes instead of mitogenomes. Parasitic plants establish vascular connections with their hosts through haustoria to obtain water and nutrients, which facilitates the exchange of genetic information, making them more susceptible to horizontal gene transfer (HGT). HGT is more prevalent in the mitochondria than in the chloroplast or nuclear compartments. SCOPE This review summarizes current knowledge on the plastid and mitochondrial genomes of holoparasitic angiosperms, compares the genomic features across the different lineages, and discusses their convergent evolutionary trajectories and distinctive features. We focused on Balanophoraceae (Santalales), which exhibits extraordinary traits in both their organelles. CONCLUSIONS Apart from morphological similarities, plastid genomes of holoparasitic plants also display other convergent features, such as rampant gene loss, biased nucleotide composition and accelerated evolutionary rates. In addition, the plastomes of Balanophoraceae have extremely low GC and gene content, and two unexpected changes in the genetic code. Limited data on the mitochondrial genomes of holoparasitic plants preclude thorough comparisons. Nonetheless, no obvious genomic features distinguish them from the mitochondria of free-living angiosperms, except for a higher incidence of HGT. HGT appears to be predominant in holoparasitic angiosperms with a long-lasting endophytic stage. Among the Balanophoraceae, mitochondrial genomes exhibit disparate evolutionary paths with notable levels of heteroplasmy in Rhopalocnemis and unprecedented levels of HGT in Lophophytum. Despite their differences, these Balanophoraceae share a multichromosomal mitogenome, a feature also found in a few free-living angiosperms.
Collapse
Affiliation(s)
- M Virginia Sanchez-Puerta
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA, Mendoza, Argentina
| | - Luis F Ceriotti
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA, Mendoza, Argentina
| | - Leonardo M Gatica-Soria
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA, Mendoza, Argentina
| | - M Emilia Roulet
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Mendoza, Argentina
| | - Laura E Garcia
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, Chacras de Coria, M5528AHB, Mendoza, Argentina
- Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA, Mendoza, Argentina
| | - Hector A Sato
- Facultad de Ciencias Agrarias, Cátedra de Botánica General–Herbario JUA, Alberdi 47, Universidad Nacional de Jujuy, 4600 Jujuy, Argentina
| |
Collapse
|
4
|
Pfennig A, Lomsadze A, Borodovsky M. MgCod: Gene Prediction in Phage Genomes with Multiple Genetic Codes. J Mol Biol 2023; 435:168159. [PMID: 37244571 DOI: 10.1016/j.jmb.2023.168159] [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: 12/01/2022] [Revised: 05/19/2023] [Accepted: 05/21/2023] [Indexed: 05/29/2023]
Abstract
Massive sequencing of microbiomes has led to the discovery of a large number of phage genomes with intermittent stop codon recoding. We have developed a computational tool, MgCod, that identifies genomic regions (blocks) with distinct stop codon recoding simultaneously with the prediction of protein-coding regions. When MgCod was used to scan a large volume of human metagenomic contigs hundreds of viral contigs with intermittent stop codon recoding were revealed. Many of these contigs originated from genomes of known crAssphages. Further analyses had shown that intermittent recoding was associated with subtle patterns in the organization of protein-coding genes, such as 'single-coding' and 'dual-coding'. The dual-coding genes, clustered into blocks, could be translated by two alternative codes producing nearly identical proteins. It was observed that the dual-coded blocks were enriched with the early-stage phage genes, while the late-stage genes were residing in the single-coded blocks. MgCod can identify types of stop codon recoding in novel genomic sequences in parallel with gene prediction. It is available for download from https://github.com/gatech-genemark/MgCod.
Collapse
Affiliation(s)
- Aaron Pfennig
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Alexandre Lomsadze
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Mark Borodovsky
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| |
Collapse
|
5
|
Kachale A, Pavlíková Z, Nenarokova A, Roithová A, Durante IM, Miletínová P, Záhonová K, Nenarokov S, Votýpka J, Horáková E, Ross RL, Yurchenko V, Beznosková P, Paris Z, Valášek LS, Lukeš J. Short tRNA anticodon stem and mutant eRF1 allow stop codon reassignment. Nature 2023; 613:751-758. [PMID: 36631608 DOI: 10.1038/s41586-022-05584-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 11/18/2022] [Indexed: 01/13/2023]
Abstract
Cognate tRNAs deliver specific amino acids to translating ribosomes according to the standard genetic code, and three codons with no cognate tRNAs serve as stop codons. Some protists have reassigned all stop codons as sense codons, neglecting this fundamental principle1-4. Here we analyse the in-frame stop codons in 7,259 predicted protein-coding genes of a previously undescribed trypanosomatid, Blastocrithidia nonstop. We reveal that in this species in-frame stop codons are underrepresented in genes expressed at high levels and that UAA serves as the only termination codon. Whereas new tRNAsGlu fully cognate to UAG and UAA evolved to reassign these stop codons, the UGA reassignment followed a different path through shortening the anticodon stem of tRNATrpCCA from five to four base pairs (bp). The canonical 5-bp tRNATrp recognizes UGG as dictated by the genetic code, whereas its shortened 4-bp variant incorporates tryptophan also into in-frame UGA. Mimicking this evolutionary twist by engineering both variants from B. nonstop, Trypanosoma brucei and Saccharomyces cerevisiae and expressing them in the last two species, we recorded a significantly higher readthrough for all 4-bp variants. Furthermore, a gene encoding B. nonstop release factor 1 acquired a mutation that specifically restricts UGA recognition, robustly potentiating the UGA reassignment. Virtually the same strategy has been adopted by the ciliate Condylostoma magnum. Hence, we describe a previously unknown, universal mechanism that has been exploited in unrelated eukaryotes with reassigned stop codons.
Collapse
Affiliation(s)
- Ambar Kachale
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic
| | - Zuzana Pavlíková
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Anna Nenarokova
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.,School of Biological Sciences, University of Bristol, Bristol, UK
| | - Adriana Roithová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Ignacio M Durante
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic
| | - Petra Miletínová
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Kristína Záhonová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic.,Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Serafim Nenarokov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic
| | - Jan Votýpka
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Faculty of Science, Charles University, BIOCEV, Prague, Czech Republic
| | - Eva Horáková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.,Institute of Microbiology, Czech Academy of Sciences, Třeboň, Czech Republic
| | | | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Petra Beznosková
- Institute of Microbiology, Czech Academy of Sciences, Prague, Czech Republic
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
| | | | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic. .,Faculty of Sciences, University of South Bohemia, České Budějovice, Czech Republic.
| |
Collapse
|
6
|
Zürcher JF, Robertson WE, Kappes T, Petris G, Elliott TS, Salmond GPC, Chin JW. Refactored genetic codes enable bidirectional genetic isolation. Science 2022; 378:516-523. [PMID: 36264827 PMCID: PMC7614150 DOI: 10.1126/science.add8943] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The near-universal genetic code defines the correspondence between codons in genes and amino acids in proteins. We refactored the structure of the genetic code in Escherichia coli and created orthogonal genetic codes that restrict the escape of synthetic genetic information into natural life. We developed orthogonal and mutually orthogonal horizontal gene transfer systems, which permit the transfer of genetic information between organisms that use the same genetic code but restrict the transfer of genetic information between organisms that use different genetic codes. Moreover, we showed that locking refactored codes into synthetic organisms completely blocks invasion by mobile genetic elements, including viruses, which carry their own translation factors and successfully invade organisms with canonical and compressed genetic codes.
Collapse
Affiliation(s)
- Jérôme F. Zürcher
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | - Tomás Kappes
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Gianluca Petris
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Thomas S. Elliott
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | - Jason W. Chin
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK,Correspondence to:
| |
Collapse
|
7
|
Matsuo E, Morita K, Nakayama T, Yazaki E, Sarai C, Takahashi K, Iwataki M, Inagaki Y. Comparative Plastid Genomics of Green-Colored Dinoflagellates Unveils Parallel Genome Compaction and RNA Editing. FRONTIERS IN PLANT SCIENCE 2022; 13:918543. [PMID: 35898209 PMCID: PMC9309888 DOI: 10.3389/fpls.2022.918543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
Dinoflagellates possess plastids that are diverse in both pigmentation and evolutionary background. One of the plastid types found in dinoflagellates is pigmented with chlorophylls a and b (Chl a + b) and originated from the endosymbionts belonging to a small group of green algae, Pedinophyceae. The Chl a + b-containing plastids have been found in three distantly related dinoflagellates Lepidodinium spp., strain MGD, and strain TGD, and were proposed to be derived from separate partnerships between a dinoflagellate (host) and a pedinophycean green alga (endosymbiont). Prior to this study, a plastid genome sequence was only available for L. chlorophorum, which was reported to bear the features that were not found in that of the pedinophycean green alga Pedinomonas minor, a putative close relative of the endosymbiont that gave rise to the current Chl a + b-containing plastid. In this study, we sequenced the plastid genomes of strains MGD and TGD to compare with those of L. chlorophorum as well as pedinophycean green algae. The mapping of the RNA-seq reads on the corresponding plastid genome identified RNA editing on plastid gene transcripts in the three dinoflagellates. Further, the comparative plastid genomics revealed that the plastid genomes of the three dinoflagellates achieved several features, which are not found in or much less obvious than the pedinophycean plastid genomes determined to date, in parallel.
Collapse
Affiliation(s)
- Eriko Matsuo
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kounosuke Morita
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takuro Nakayama
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan
| | | | - Chihiro Sarai
- Graduate School of Science and Engineering, Yamagata University, Yamagata, Japan
| | - Kazuya Takahashi
- Asian Natural Environmental Science Center, The University of Tokyo, Tokyo, Japan
| | - Mitsunori Iwataki
- Asian Natural Environmental Science Center, The University of Tokyo, Tokyo, Japan
| | - Yuji Inagaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- Center for Computational Sciences, University of Tsukuba, Tsukuba, Japan
| |
Collapse
|
8
|
Borges AL, Lou YC, Sachdeva R, Al-Shayeb B, Penev PI, Jaffe AL, Lei S, Santini JM, Banfield JF. Widespread stop-codon recoding in bacteriophages may regulate translation of lytic genes. Nat Microbiol 2022; 7:918-927. [PMID: 35618772 DOI: 10.1038/s41564-022-01128-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 04/21/2022] [Indexed: 11/09/2022]
Abstract
Bacteriophages (phages) are obligate parasites that use host bacterial translation machinery to produce viral proteins. However, some phages have alternative genetic codes with reassigned stop codons that are predicted to be incompatible with bacterial translation systems. We analysed 9,422 phage genomes and found that stop-codon recoding has evolved in diverse clades of phages that infect bacteria present in both human and animal gut microbiota. Recoded stop codons are particularly over-represented in phage structural and lysis genes. We propose that recoded stop codons might function to prevent premature production of late-stage proteins. Stop-codon recoding has evolved several times in closely related lineages, which suggests that adaptive recoding can occur over very short evolutionary timescales.
Collapse
Affiliation(s)
- Adair L Borges
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.,Environmental Science, Policy and Management, University of California, Berkeley, CA, USA
| | - Yue Clare Lou
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Rohan Sachdeva
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.,Earth and Planetary Science, University of California, Berkeley, CA, USA
| | - Basem Al-Shayeb
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Petar I Penev
- Earth and Planetary Science, University of California, Berkeley, CA, USA
| | - Alexander L Jaffe
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Shufei Lei
- Earth and Planetary Science, University of California, Berkeley, CA, USA
| | - Joanne M Santini
- Department of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
| | - Jillian F Banfield
- Innovative Genomics Institute, University of California, Berkeley, CA, USA. .,Environmental Science, Policy and Management, University of California, Berkeley, CA, USA. .,Earth and Planetary Science, University of California, Berkeley, CA, USA. .,Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,The University of Melbourne, Parkville, Victoria, Australia.
| |
Collapse
|
9
|
Potapova NA. Nonsense Mutations in Eukaryotes. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:400-412. [PMID: 35790376 DOI: 10.1134/s0006297922050029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/14/2022] [Accepted: 03/22/2022] [Indexed: 06/15/2023]
Abstract
Nonsense mutations are a type of mutations which results in a premature termination codon occurrence. In general, these mutations have been considered to be among the most harmful ones which lead to premature protein translation termination and result in shortened nonfunctional polypeptide. However, there is evidence that not all nonsense mutations are harmful as well as some molecular mechanisms exist which allow to avoid pathogenic effects of these mutations. This review addresses relevant information on nonsense mutations in eukaryotic genomes, characteristics of these mutations, and different molecular mechanisms preventing or mitigating harmful effects thereof.
Collapse
Affiliation(s)
- Nadezhda A Potapova
- Kharkevich Institute for Information Transmission Problems (IITP), Russian Academy of Sciences, Moscow, 127051, Russia.
| |
Collapse
|
10
|
Formation of the Codon Degeneracy during Interdependent Development between Metabolism and Replication. Genes (Basel) 2021; 12:genes12122023. [PMID: 34946975 PMCID: PMC8701183 DOI: 10.3390/genes12122023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 11/16/2022] Open
Abstract
Nirenberg's genetic code chart shows a profound correspondence between codons and amino acids. The aim of this article is to try to explain the primordial formation of the codon degeneracy. It remains a puzzle how informative molecules arose from the supposed prebiotic random sequences. If introducing an initial driving force based on the relative stabilities of triplex base pairs, the prebiotic sequence evolution became innately nonrandom. Thus, the primordial assignment of the 64 codons to the 20 amino acids has been explained in detail according to base substitutions during the coevolution of tRNAs with aaRSs; meanwhile, the classification of aaRSs has also been explained.
Collapse
|
11
|
Shulgina Y, Eddy SR. A computational screen for alternative genetic codes in over 250,000 genomes. eLife 2021; 10:71402. [PMID: 34751130 PMCID: PMC8629427 DOI: 10.7554/elife.71402] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/26/2021] [Indexed: 11/25/2022] Open
Abstract
The genetic code has been proposed to be a ‘frozen accident,’ but the discovery of alternative genetic codes over the past four decades has shown that it can evolve to some degree. Since most examples were found anecdotally, it is difficult to draw general conclusions about the evolutionary trajectories of codon reassignment and why some codons are affected more frequently. To fill in the diversity of genetic codes, we developed Codetta, a computational method to predict the amino acid decoding of each codon from nucleotide sequence data. We surveyed the genetic code usage of over 250,000 bacterial and archaeal genome sequences in GenBank and discovered five new reassignments of arginine codons (AGG, CGA, and CGG), representing the first sense codon changes in bacteria. In a clade of uncultivated Bacilli, the reassignment of AGG to become the dominant methionine codon likely evolved by a change in the amino acid charging of an arginine tRNA. The reassignments of CGA and/or CGG were found in genomes with low GC content, an evolutionary force that likely helped drive these codons to low frequency and enable their reassignment. All life forms rely on a ‘code’ to translate their genetic information into proteins. This code relies on limited permutations of three nucleotides – the building blocks that form DNA and other types of genetic information. Each ‘triplet’ of nucleotides – or codon – encodes a specific amino acid, the basic component of proteins. Reading the sequence of codons in the right order will let the cell know which amino acid to assemble next on a growing protein. For instance, the codon CGG – formed of the nucleotides guanine (G) and cytosine (C) – codes for the amino acid arginine. From bacteria to humans, most life forms rely on the same genetic code. Yet certain organisms have evolved to use slightly different codes, where one or several codons have an altered meaning. To better understand how alternative genetic codes have evolved, Shulgina and Eddy set out to find more organisms featuring these altered codons, creating a new software called Codetta that can analyze the genome of a microorganism and predict the genetic code it uses. Codetta was then used to sift through the genetic information of 250,000 microorganisms. This was made possible by the sequencing, in recent years, of the genomes of hundreds of thousands of bacteria and other microorganisms – including many never studied before. These analyses revealed five groups of bacteria with alternative genetic codes, all of which had changes in the codons that code for arginine. Amongst these, four had genomes with a low proportion of guanine and cytosine nucleotides. This may have made some guanine and cytosine-rich arginine codons very rare in these organisms and, therefore, easier to be reassigned to encode another amino acid. The work by Shulgina and Eddy demonstrates that Codetta is a new, useful tool that scientists can use to understand how genetic codes evolve. In addition, it can also help to ensure the accuracy of widely used protein databases, which assume which genetic code organisms use to predict protein sequences from their genomes.
Collapse
Affiliation(s)
| | - Sean R Eddy
- Molecular & Cellular Biology, Harvard University, Cambridge, United States
| |
Collapse
|
12
|
Robertson WE, Funke LFH, de la Torre D, Fredens J, Elliott TS, Spinck M, Christova Y, Cervettini D, Böge FL, Liu KC, Buse S, Maslen S, Salmond GPC, Chin JW. Sense codon reassignment enables viral resistance and encoded polymer synthesis. Science 2021; 372:1057-1062. [PMID: 34083482 DOI: 10.1126/science.abg3029] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/08/2021] [Indexed: 12/13/2022]
Abstract
It is widely hypothesized that removing cellular transfer RNAs (tRNAs)-making their cognate codons unreadable-might create a genetic firewall to viral infection and enable sense codon reassignment. However, it has been impossible to test these hypotheses. In this work, following synonymous codon compression and laboratory evolution in Escherichia coli, we deleted the tRNAs and release factor 1, which normally decode two sense codons and a stop codon; the resulting cells could not read the canonical genetic code and were completely resistant to a cocktail of viruses. We reassigned these codons to enable the efficient synthesis of proteins containing three distinct noncanonical amino acids. Notably, we demonstrate the facile reprogramming of our cells for the encoded translation of diverse noncanonical heteropolymers and macrocycles.
Collapse
Affiliation(s)
| | - Louise F H Funke
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | - Julius Fredens
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Thomas S Elliott
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Martin Spinck
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Yonka Christova
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | - Franz L Böge
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Kim C Liu
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Salvador Buse
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Sarah Maslen
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | | | - Jason W Chin
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
| |
Collapse
|
13
|
Ogoh K, Futahashi R, Ohmiya Y. Intraspecific nucleotide polymorphisms in seven complete sequences of mitochondrial DNA of the luminous ostracod, Vargula hilgendorfii (Crustacea, Ostracoda). GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
14
|
Ceriotti LF, Roulet ME, Sanchez-Puerta MV. Plastomes in the holoparasitic family Balanophoraceae: Extremely high AT content, severe gene content reduction, and two independent genetic code changes. Mol Phylogenet Evol 2021; 162:107208. [PMID: 34029719 DOI: 10.1016/j.ympev.2021.107208] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 05/11/2021] [Accepted: 05/19/2021] [Indexed: 12/29/2022]
Abstract
The transition to a heterotrophic lifestyle in angiosperms is characterized by convergent evolutionary changes. Plastid genome remodeling includes dramatic functional and physical reductions with the highest degrees observed in fully heterotrophic plants. Genes related to photosynthesis are generally absent or pseudogenized, while a few genes related to other metabolic processes that take place within the plastid are almost invariably maintained. The family Balanophoraceae consists of root holoparasites that present reduced plastid genomes with an extraordinarily elevated AT content and the single genetic code change ever documented in land plant plastomes (the stop codon TAG now codes for tryptophan). Here, we studied the plastomes of Lophophytum leandri and Ombrophytum subterraneum (Balanophoraceae) that showed the remarkable absence of the gene trnE, a highly biased nucleotide composition, and an independent genetic code change (the standard stop codon TGA codes for tryptophan). This is the second genetic code change identified in land plant plastomes. Analysis of the transcriptome of Lophophytum indicated that the entire C5 pathway typical of plants is conserved despite the lack of trnE in its plastome. A hypothetical model of plastome evolution in the Balanophoraceae is presented.
Collapse
Affiliation(s)
- Luis Federico Ceriotti
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, M5528AHB Chacras de Coria, Argentina; Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA Mendoza, Argentina
| | - M Emilia Roulet
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, M5528AHB Chacras de Coria, Argentina
| | - M Virginia Sanchez-Puerta
- IBAM, Universidad Nacional de Cuyo, CONICET, Facultad de Ciencias Agrarias, Almirante Brown 500, M5528AHB Chacras de Coria, Argentina; Facultad de Ciencias Exactas y Naturales, Padre Jorge Contreras 1300, Universidad Nacional de Cuyo, M5502JMA Mendoza, Argentina.
| |
Collapse
|
15
|
Muñoz-Gómez SA, Bilolikar G, Wideman JG, Geiler-Samerotte K. Constructive Neutral Evolution 20 Years Later. J Mol Evol 2021; 89:172-182. [PMID: 33604782 PMCID: PMC7982386 DOI: 10.1007/s00239-021-09996-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/13/2021] [Indexed: 12/29/2022]
Abstract
Evolution has led to a great diversity that ranges from elegant simplicity to ornate complexity. Many complex features are often assumed to be more functional or adaptive than their simpler alternatives. However, in 1999, Arlin Stolzfus published a paper in the Journal of Molecular Evolution that outlined a framework in which complexity can arise through a series of non-adaptive steps. He called this framework Constructive Neutral Evolution (CNE). Despite its two-decade-old roots, many evolutionary biologists still appear to be unaware of this explanatory framework for the origins of complexity. In this perspective piece, we explain the theory of CNE and how it changes the order of events in narratives that describe the evolution of complexity. We also provide an extensive list of cellular features that may have become more complex through CNE. We end by discussing strategies to determine whether complexity arose through neutral or adaptive processes.
Collapse
Affiliation(s)
- Sergio A Muñoz-Gómez
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
| | - Gaurav Bilolikar
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Jeremy G Wideman
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Kerry Geiler-Samerotte
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
| |
Collapse
|
16
|
Belinky F, Ganguly I, Poliakov E, Yurchenko V, Rogozin IB. Analysis of Stop Codons within Prokaryotic Protein-Coding Genes Suggests Frequent Readthrough Events. Int J Mol Sci 2021; 22:ijms22041876. [PMID: 33672790 PMCID: PMC7918605 DOI: 10.3390/ijms22041876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 02/07/2023] Open
Abstract
Nonsense mutations turn a coding (sense) codon into an in-frame stop codon that is assumed to result in a truncated protein product. Thus, nonsense substitutions are the hallmark of pseudogenes and are used to identify them. Here we show that in-frame stop codons within bacterial protein-coding genes are widespread. Their evolutionary conservation suggests that many of them are not pseudogenes, since they maintain dN/dS values (ratios of substitution rates at non-synonymous and synonymous sites) significantly lower than 1 (this is a signature of purifying selection in protein-coding regions). We also found that double substitutions in codons—where an intermediate step is a nonsense substitution—show a higher rate of evolution compared to null models, indicating that a stop codon was introduced and then changed back to sense via positive selection. This further supports the notion that nonsense substitutions in bacteria are relatively common and do not necessarily cause pseudogenization. In-frame stop codons may be an important mechanism of regulation: Such codons are likely to cause a substantial decrease of protein expression levels.
Collapse
Affiliation(s)
- Frida Belinky
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA; (F.B.); (I.G.)
| | - Ishan Ganguly
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA; (F.B.); (I.G.)
| | - Eugenia Poliakov
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA;
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, 119435 Moscow, Russia
- Correspondence: (V.Y.); (I.B.R.)
| | - Igor B. Rogozin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA; (F.B.); (I.G.)
- Correspondence: (V.Y.); (I.B.R.)
| |
Collapse
|
17
|
Abstract
Wobble coding is inevitable during evolution of the Standard Genetic Code (SGC). It ultimately splits half of NN U/C/A/G coding boxes with different assignments. Further, it contributes to pervasive SGC order by reinforcing close spacing for identical SGC assignments. But wobble cannot appear too soon, or it will inhibit encoding and more decisively, obstruct evolution of full coding tables. However, these prior results assumed Crick wobble, NN U/C and NN A/G, read by a single adaptor RNA. Superwobble translates NN U/C/A/G codons, using one adaptor RNA with an unmodified 5' anticodon U (appropriate to earliest coding) in modern mitochondria, plastids, and mycoplasma. Assuming the SGC was selected when evolving codes most resembled it, characteristics of the critical selection events can be calculated. For example, continuous superwobble infrequently evolves SGC-like coding tables. So, continuous superwobble is a very improbable origin hypothesis. In contrast, late-arising superwobble shares late Crick wobble's frequent resemblance to SGC order. Thus late superwobble is possible, but yields SGC-like assignments less frequently than late Crick wobble. Ancient coding ambiguity, most simply, arose from Crick wobble alone. This is consistent with SGC assignments to NAN codons.
Collapse
Affiliation(s)
- Michael Yarus
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309-0347, USA.
| |
Collapse
|
18
|
Singh T, Yadav SK, Vainstein A, Kumar V. Genome recoding strategies to improve cellular properties: mechanisms and advances. ABIOTECH 2021; 2:79-95. [PMID: 34377578 PMCID: PMC7675020 DOI: 10.1007/s42994-020-00030-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/07/2020] [Indexed: 11/10/2022]
Abstract
The genetic code, once believed to be universal and immutable, is now known to contain many variations and is not quite universal. The basis for genome recoding strategy is genetic code variation that can be harnessed to improve cellular properties. Thus, genome recoding is a promising strategy for the enhancement of genome flexibility, allowing for novel functions that are not commonly documented in the organism in its natural environment. Here, the basic concept of genetic code and associated mechanisms for the generation of genetic codon variants, including biased codon usage, codon reassignment, and ambiguous decoding, are extensively discussed. Knowledge of the concept of natural genetic code expansion is also detailed. The generation of recoded organisms and associated mechanisms with basic targeting components, including aminoacyl-tRNA synthetase-tRNA pairs, elongation factor EF-Tu and ribosomes, are highlighted for a comprehensive understanding of this concept. The research associated with the generation of diverse recoded organisms is also discussed. The success of genome recoding in diverse multicellular organisms offers a platform for expanding protein chemistry at the biochemical level with non-canonical amino acids, genetically isolating the synthetic organisms from the natural ones, and fighting viruses, including SARS-CoV2, through the creation of attenuated viruses. In conclusion, genome recoding can offer diverse applications for improving cellular properties in the genome-recoded organisms.
Collapse
Affiliation(s)
- Tanya Singh
- Department of Botany, School of Basic Sciences, Central University of Punjab, Bathinda, 151001 India
| | | | - Alexander Vainstein
- Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Vinay Kumar
- Department of Botany, School of Basic Sciences, Central University of Punjab, Bathinda, 151001 India
| |
Collapse
|
19
|
Demongeot J, Seligmann H. Codon assignment evolvability in theoretical minimal RNA rings. Gene 2020; 769:145208. [PMID: 33031892 DOI: 10.1016/j.gene.2020.145208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 12/28/2022]
Abstract
Genetic code codon-amino acid assignments evolve for 15 (AAA, AGA, AGG, ATA, CGG, CTA, CTG. CTC, CTT, TAA, TAG, TCA, TCG, TGA and TTA (GNN codons notably absent)) among 64 codons (23.4%) across the 31 genetic codes (NCBI list completed with recently suggested green algal mitochondrial genetic codes). Their usage in 25 theoretical minimal RNA rings is examined. RNA rings are designed in silico to code once over the shortest length for all 22 coding signals (start and stop codons and each amino acid according to the standard genetic code). Though designed along coding constraints, RNA rings resemble ancestral tRNA loops, assigning to each RNA ring a putative anticodon, a cognate amino acid and an evolutionary genetic code integration rank for that cognate amino acid. Analyses here show 1. biases against/for evolvable codons in the two first vs last thirds of RNA ring coding sequences, 2. RNA rings with evolvable codons have recent cognates, and 3. evolvable codon and cytosine numbers in RNA ring compositions are positively correlated. Applying alternative genetic codes to RNA rings designed for nonredundant coding according to the standard genetic code reveals unsuspected properties of the standard genetic code and of RNA rings, notably on codon assignment evolvability and the special role of cytosine in relation to codon assignment evolvability and of the genetic code's coding structure.
Collapse
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
- The National Natural History Collections, The Hebrew University of Jerusalem, 91404 Jerusalem, Israel.
| |
Collapse
|
20
|
Genetic codes optimized as a traveling salesman problem. PLoS One 2019; 14:e0224552. [PMID: 31658301 PMCID: PMC6816573 DOI: 10.1371/journal.pone.0224552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 10/16/2019] [Indexed: 11/19/2022] Open
Abstract
The Standard Genetic Code (SGC) is robust to mutational errors such that frequently occurring mutations minimally alter the physio-chemistry of amino acids. The apparent correlation between the evolutionary distances among codons and the physio-chemical distances among their cognate amino acids suggests an early co-diversification between the codons and amino acids. Here we formulated the co-minimization of evolutionary distances between codons and physio-chemical distances between amino acids as a Traveling Salesman Problem (TSP) and solved it with a Hopfield neural network. In this unsupervised learning algorithm, macromolecules (e.g., tRNAs and aminoacyl-tRNA synthetases) associating codons with amino acids were considered biological analogs of Hopfield neurons associating "tour cities" with "tour positions". The Hopfield network efficiently yielded an abundance of genetic codes that were more error-minimizing than SGC and could thus be used to design artificial genetic codes. We further argue that as a self-optimization algorithm, the Hopfield neural network provides a model of origin of SGC and other adaptive molecular systems through evolutionary learning.
Collapse
|
21
|
Noutahi E, Calderon V, Blanchette M, El-Mabrouk N, Lang BF. Rapid Genetic Code Evolution in Green Algal Mitochondrial Genomes. Mol Biol Evol 2019; 36:766-783. [PMID: 30698742 PMCID: PMC6551751 DOI: 10.1093/molbev/msz016] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Genetic code deviations involving stop codons have been previously reported in mitochondrial genomes of several green plants (Viridiplantae), most notably chlorophyte algae (Chlorophyta). However, as changes in codon recognition from one amino acid to another are more difficult to infer, such changes might have gone unnoticed in particular lineages with high evolutionary rates that are otherwise prone to codon reassignments. To gain further insight into the evolution of the mitochondrial genetic code in green plants, we have conducted an in-depth study across mtDNAs from 51 green plants (32 chlorophytes and 19 streptophytes). Besides confirming known stop-to-sense reassignments, our study documents the first cases of sense-to-sense codon reassignments in Chlorophyta mtDNAs. In several Sphaeropleales, we report the decoding of AGG codons (normally arginine) as alanine, by tRNA(CCU) of various origins that carry the recognition signature for alanine tRNA synthetase. In Chromochloris, we identify tRNA variants decoding AGG as methionine and the synonymous codon CGG as leucine. Finally, we find strong evidence supporting the decoding of AUA codons (normally isoleucine) as methionine in Pycnococcus. Our results rely on a recently developed conceptual framework (CoreTracker) that predicts codon reassignments based on the disparity between DNA sequence (codons) and the derived protein sequence. These predictions are then validated by an evaluation of tRNA phylogeny, to identify the evolution of new tRNAs via gene duplication and loss, and structural modifications that lead to the assignment of new tRNA identities and a change in the genetic code.
Collapse
Affiliation(s)
- Emmanuel Noutahi
- Département d'Informatique et de Recherche opérationnelle (DIRO), Université de Montréal, CP 6128 succursale Centre-Ville, Montreal, QC, Canada
| | - Virginie Calderon
- Institut de Recherches Cliniques de Montréal, Montreal, Quebec, Canada
| | - Mathieu Blanchette
- School of Computer Science, McGill University, McConnell Engineering Bldg., Montréal, QC H3A 0E9, Canada
- McGill Centre for Bioinformatics, McGill University, Montréal, QC, Canada
| | - Nadia El-Mabrouk
- Département d'Informatique et de Recherche opérationnelle (DIRO), Université de Montréal, CP 6128 succursale Centre-Ville, Montreal, QC, Canada
| | - Bernd Franz Lang
- Département de Biochimie, Centre Robert Cedergren, Université de Montréal, CP 6128 succursale Centre-Ville, Montreal, QC, Canada
| |
Collapse
|
22
|
Many alternative and theoretical genetic codes are more robust to amino acid replacements than the standard genetic code. J Theor Biol 2019; 464:21-32. [DOI: 10.1016/j.jtbi.2018.12.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 02/07/2023]
|
23
|
Smith DR. Evolution: A Plant Plastid Genome that Has Forsaken Guanine and Cytosine. Curr Biol 2019; 29:R99-R101. [PMID: 30721685 DOI: 10.1016/j.cub.2018.12.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The plastid genomes of the non-photosynthetic plants Balanophora reflexa and B. laxiflora are among the most GC-biased genomes observed to date. A new study shows that ∼80% of the plastid-derived proteome is represented by only six amino acids, and several genes are in excess of 95% AT.
Collapse
Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, ON, Canada.
| |
Collapse
|
24
|
Su HJ, Barkman TJ, Hao W, Jones SS, Naumann J, Skippington E, Wafula EK, Hu JM, Palmer JD, dePamphilis CW. Novel genetic code and record-setting AT-richness in the highly reduced plastid genome of the holoparasitic plant Balanophora. Proc Natl Acad Sci U S A 2019; 116:934-943. [PMID: 30598433 PMCID: PMC6338844 DOI: 10.1073/pnas.1816822116] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plastid genomes (plastomes) vary enormously in size and gene content among the many lineages of nonphotosynthetic plants, but key lineages remain unexplored. We therefore investigated plastome sequence and expression in the holoparasitic and morphologically bizarre Balanophoraceae. The two Balanophora plastomes examined are remarkable, exhibiting features rarely if ever seen before in plastomes or in any other genomes. At 15.5 kb in size and with only 19 genes, they are among the most reduced plastomes known. They have no tRNA genes for protein synthesis, a trait found in only three other plastid lineages, and thus Balanophora plastids must import all tRNAs needed for translation. Balanophora plastomes are exceptionally compact, with numerous overlapping genes, highly reduced spacers, loss of all cis-spliced introns, and shrunken protein genes. With A+T contents of 87.8% and 88.4%, the Balanophora genomes are the most AT-rich genomes known save for a single mitochondrial genome that is merely bloated with AT-rich spacer DNA. Most plastid protein genes in Balanophora consist of ≥90% AT, with several between 95% and 98% AT, resulting in the most biased codon usage in any genome described to date. A potential consequence of its radical compositional evolution is the novel genetic code used by Balanophora plastids, in which TAG has been reassigned from stop to tryptophan. Despite its many exceptional properties, the Balanophora plastome must be functional because all examined genes are transcribed, its only intron is correctly trans-spliced, and its protein genes, although highly divergent, are evolving under various degrees of selective constraint.
Collapse
Affiliation(s)
- Huei-Jiun Su
- Department of Earth and Life Sciences, University of Taipei, 100 Taipei, Taiwan
- Department of Biology, Pennsylvania State University, University Park, PA 16802
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
| | - Todd J Barkman
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI 49008
| | - Weilong Hao
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202
| | - Samuel S Jones
- Graduate Program in Plant Biology, Pennsylvania State University, University Park, PA 16802
| | - Julia Naumann
- Department of Biology, Pennsylvania State University, University Park, PA 16802
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
| | | | - Eric K Wafula
- Department of Biology, Pennsylvania State University, University Park, PA 16802
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
| | - Jer-Ming Hu
- Institute of Ecology and Evolutionary Biology, National Taiwan University, 106 Taipei, Taiwan
| | - Jeffrey D Palmer
- Department of Biology, Indiana University, Bloomington, IN 47405;
| | - Claude W dePamphilis
- Department of Biology, Pennsylvania State University, University Park, PA 16802;
- Institute of Molecular Evolutionary Genetics, Pennsylvania State University, University Park, PA 16802
- Graduate Program in Plant Biology, Pennsylvania State University, University Park, PA 16802
| |
Collapse
|
25
|
Li Y, Kocot KM, Tassia MG, Cannon JT, Bernt M, Halanych KM. Mitogenomics Reveals a Novel Genetic Code in Hemichordata. Genome Biol Evol 2019; 11:29-40. [PMID: 30476024 PMCID: PMC6319601 DOI: 10.1093/gbe/evy254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2018] [Indexed: 01/26/2023] Open
Abstract
The diverse array of codon reassignments demonstrate that the genetic code is not universal in nature. Exploring mechanisms underlying codon reassignment is critical for understanding the evolution of the genetic code during translation. Hemichordata, comprising worm-like Enteropneusta and colonial filter-feeding Pterobranchia, is the sister taxon of echinoderms and is more distantly related to chordates. However, only a few hemichordate mitochondrial genomes have been sequenced, hindering our understanding of mitochondrial genome evolution within Deuterostomia. In this study, we sequenced four mitochondrial genomes and two transcriptomes, including representatives of both major hemichordate lineages and analyzed together with public available data. Contrary to the current understanding of the mitochondrial genetic code in hemichordates, our comparative analyses suggest that UAA encodes Tyr instead of a "Stop" codon in the pterobranch lineage Cephalodiscidae. We also predict that AAA encodes Lys in pterobranch and enteropneust mitochondrial genomes, contradicting the previous assumption that hemichordates share the same genetic code with echinoderms for which AAA encodes Asn. Thus, we propose a new mitochondrial genetic code for Cephalodiscus and a revised code for enteropneusts. Moreover, our phylogenetic analyses are largely consistent with previous phylogenomic studies. The only exception is the phylogenetic position of the enteropneust Stereobalanus, whose placement as sister to all other described enteropneusts. With broader taxonomic sampling, we provide evidence that evolution of mitochondrial gene order and genetic codes in Hemichordata are more dynamic than previously thought and these findings provide insights into mitochondrial genome evolution within this clade.
Collapse
Affiliation(s)
- Yuanning Li
- Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University
| | - Kevin M Kocot
- Department of Biological Sciences & Alabama Museum of Natural History, The University of Alabama
| | - Michael G Tassia
- Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University
| | - Johanna T Cannon
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara
| | - Matthias Bernt
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Kenneth M Halanych
- Department of Biological Sciences & Molette Biology Laboratory for Environmental and Climate Change Studies, Auburn University
| |
Collapse
|
26
|
Synonymous Codon Usages as an Evolutionary Dynamic for Chlamydiaceae. Int J Mol Sci 2018; 19:ijms19124010. [PMID: 30545112 PMCID: PMC6321445 DOI: 10.3390/ijms19124010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 12/06/2018] [Accepted: 12/10/2018] [Indexed: 01/08/2023] Open
Abstract
The family of Chlamydiaceae contains a group of obligate intracellular bacteria that can infect a wide range of hosts. The evolutionary trend of members in this family is a hot topic, which benefits our understanding of the cross-infection of these pathogens. In this study, 14 whole genomes of 12 Chlamydia species were used to investigate the nucleotide, codon, and amino acid usage bias by synonymous codon usage value and information entropy method. The results showed that all the studied Chlamydia spp. had A/T rich genes with over-represented A or T at the third positions and G or C under-represented at these positions, suggesting that nucleotide usages influenced synonymous codon usages. The overall codon usage trend from synonymous codon usage variations divides the Chlamydia spp. into four separate clusters, while amino acid usage divides the Chlamydia spp. into two clusters with some exceptions, which reflected the genetic diversity of the Chlamydiaceae family members. The overall codon usage pattern represented by the effective number of codons (ENC) was significantly positively correlated to gene GC3 content. A negative correlation exists between ENC and the codon adaptation index for some Chlamydia species. These results suggested that mutation pressure caused by nucleotide composition constraint played an important role in shaping synonymous codon usage patterns. Furthermore, codon usage of T3ss and Pmps gene families adapted to that of the corresponding genome. Taken together, analyses help our understanding of evolutionary interactions between nucleotide, synonymous codon, and amino acid usages in genes of Chlamydiaceae family members.
Collapse
|
27
|
Noutahi E, Calderon V, Blanchette M, Lang FB, El-Mabrouk N. CoreTracker: accurate codon reassignment prediction, applied to mitochondrial genomes. Bioinformatics 2018; 33:3331-3339. [PMID: 28655158 DOI: 10.1093/bioinformatics/btx421] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/23/2017] [Indexed: 11/13/2022] Open
Abstract
Motivation Codon reassignments have been reported across all domains of life. With the increasing number of sequenced genomes, the development of systematic approaches for genetic code detection is essential for accurate downstream analyses. Three automated prediction tools exist so far: FACIL, GenDecoder and Bagheera; the last two respectively restricted to metazoan mitochondrial genomes and CUG reassignments in yeast nuclear genomes. These tools can only analyze a single genome at a time and are often not followed by a validation procedure, resulting in a high rate of false positives. Results We present CoreTracker, a new algorithm for the inference of sense-to-sense codon reassignments. CoreTracker identifies potential codon reassignments in a set of related genomes, then uses statistical evaluations and a random forest classifier to predict those that are the most likely to be correct. Predicted reassignments are then validated through a phylogeny-aware step that evaluates the impact of the new genetic code on the protein alignment. Handling simultaneously a set of genomes in a phylogenetic framework, allows tracing back the evolution of each reassignment, which provides information on its underlying mechanism. Applied to metazoan and yeast genomes, CoreTracker significantly outperforms existing methods on both precision and sensitivity. Availability and implementation CoreTracker is written in Python and available at https://github.com/UdeM-LBIT/CoreTracker. Contact mabrouk@iro.umontreal.ca. Supplementary information Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- Emmanuel Noutahi
- Département d'Informatique et de Recherche Opérationnelle (DIRO), Université de Montréal, Montréal, QC CP 6128, Canada
| | - Virginie Calderon
- Département d'Informatique et de Recherche Opérationnelle (DIRO), Université de Montréal, Montréal, QC CP 6128, Canada
| | - Mathieu Blanchette
- School of Computer Science, McGill University, McConnell Engineering Bldg., Montréal, QC H3A 0E9, Canada
| | - Franz B Lang
- Département de Biochimie, Centre Robert Cedergren, Université de Montréal, Montréal, QC CP 6128, Canada
| | - Nadia El-Mabrouk
- Département d'Informatique et de Recherche Opérationnelle (DIRO), Université de Montréal, Montréal, QC CP 6128, Canada
| |
Collapse
|
28
|
Mühlhausen S, Schmitt HD, Pan KT, Plessmann U, Urlaub H, Hurst LD, Kollmar M. Endogenous Stochastic Decoding of the CUG Codon by Competing Ser- and Leu-tRNAs in Ascoidea asiatica. Curr Biol 2018; 28:2046-2057.e5. [PMID: 29910077 PMCID: PMC6041473 DOI: 10.1016/j.cub.2018.04.085] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 04/22/2018] [Accepted: 04/24/2018] [Indexed: 12/24/2022]
Abstract
Although the “universal” genetic code is now known not to be universal, and stop codons can have multiple meanings, one regularity remains, namely that for a given sense codon there is a unique translation. Examining CUG usage in yeasts that have transferred CUG away from leucine, we here report the first example of dual coding: Ascoidea asiatica stochastically encodes CUG as both serine and leucine in approximately equal proportions. This is deleterious, as evidenced by CUG codons being rare, never at conserved serine or leucine residues, and predominantly in lowly expressed genes. Related yeasts solve the problem by loss of function of one of the two tRNAs. This dual coding is consistent with the tRNA-loss-driven codon reassignment hypothesis, and provides a unique example of a proteome that cannot be deterministically predicted. Video Abstract
Ascoidea asiatica stochastically encodes CUG as leucine and serine It is the only known example of a proteome with non-deterministic features Stochastic encoding is caused by competing tRNALeu(CAG) and tRNASer(CAG) A. asiatica copes with stochastic encoding by avoiding CUG at key positions
Collapse
Affiliation(s)
- Stefanie Mühlhausen
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Hans Dieter Schmitt
- Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Kuan-Ting Pan
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Uwe Plessmann
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany; Bioanalytics Group, Department of Clinical Chemistry, University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen, Germany
| | - Laurence D Hurst
- The Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - Martin Kollmar
- Group Systems Biology of Motor Proteins, Department of NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
| |
Collapse
|
29
|
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]
|
30
|
Ma XX, Ma P, Chang QY, Liu ZB, Zhang D, Zhou XK, Ma ZR, Cao X. Adaptation ofBorrelia burgdorferito its natural hosts by synonymous codon and amino acid usage. J Basic Microbiol 2018. [DOI: 10.1002/jobm.201700652] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Xiao-Xia Ma
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| | - Peng Ma
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| | - Qiu-Yan Chang
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| | - Zhen-Bin Liu
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| | - Derong Zhang
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| | - Xiao-Kai Zhou
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| | - Zhong-Ren Ma
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| | - Xin Cao
- Engineering and Technology Research Center for Animal Cell, Gansu; College of Life Science and Engineering; Northwest Minzu University; Gansu P.R. China
| |
Collapse
|
31
|
Lo WS, Huang YY, Kuo CH. Winding paths to simplicity: genome evolution in facultative insect symbionts. FEMS Microbiol Rev 2018; 40:855-874. [PMID: 28204477 PMCID: PMC5091035 DOI: 10.1093/femsre/fuw028] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/28/2016] [Accepted: 07/10/2016] [Indexed: 02/07/2023] Open
Abstract
Symbiosis between organisms is an important driving force in evolution. Among the diverse relationships described, extensive progress has been made in insect–bacteria symbiosis, which improved our understanding of the genome evolution in host-associated bacteria. Particularly, investigations on several obligate mutualists have pushed the limits of what we know about the minimal genomes for sustaining cellular life. To bridge the gap between those obligate symbionts with extremely reduced genomes and their non-host-restricted ancestors, this review focuses on the recent progress in genome characterization of facultative insect symbionts. Notable cases representing various types and stages of host associations, including those from multiple genera in the family Enterobacteriaceae (class Gammaproteobacteria), Wolbachia (Alphaproteobacteria) and Spiroplasma (Mollicutes), are discussed. Although several general patterns of genome reduction associated with the adoption of symbiotic relationships could be identified, extensive variation was found among these facultative symbionts. These findings are incorporated into the established conceptual frameworks to develop a more detailed evolutionary model for the discussion of possible trajectories. In summary, transitions from facultative to obligate symbiosis do not appear to be a universal one-way street; switches between hosts and lifestyles (e.g. commensalism, parasitism or mutualism) occur frequently and could be facilitated by horizontal gene transfer. This review synthesizes the recent progress in genome characterization of insect-symbiotic bacteria, the emphases include (i) patterns of genome organization, (ii) evolutionary models and trajectories, and (iii) comparisons between facultative and obligate symbionts.
Collapse
Affiliation(s)
- Wen-Sui Lo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei 11529, Taiwan.,Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ya-Yi Huang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei 11529, Taiwan.,Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| |
Collapse
|
32
|
Reviewing evidence for systematic transcriptional deletions, nucleotide exchanges, and expanded codons, and peptide clusters in human mitochondria. Biosystems 2017; 160:10-24. [PMID: 28807694 DOI: 10.1016/j.biosystems.2017.08.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/26/2017] [Accepted: 08/04/2017] [Indexed: 12/12/2022]
Abstract
Polymerization sometimes transforms sequences by (a) systematic deletions of mono-, dinucleotides after trinucleotides, or (b) 23 systematic nucleotide exchanges (9 symmetric, X<>Y, e.g. G<>T, 14 asymmetric, X > Y > Z > X, e.g. A > G > T > A), producing del- and swinger RNAs. Some peptides correspond to del- and swinger RNA translations, also according to tetracodons, codons expanded by a silent nucleotide. Here new analyzes assume different proteolytic patterns, partially alleviating false negative peptide detection biases, expanding noncanonical mitoproteome profiles. Mito-genomic, -transcriptomic and -proteomic evidence for noncanonical transcriptions and translations are reviewed and clusters of del- and swinger peptides (also along tetracodons) are described. Noncanonical peptide clusters indicate regulated expression of cryptically encoded mitochondrial protein coding genes. These candidate noncanonical proteins don't resemble known proteins.
Collapse
|
33
|
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]
|
34
|
Evolving Mistranslating tRNAs Through a Phenotypically Ambivalent Intermediate in Saccharomyces cerevisiae. Genetics 2017; 206:1865-1879. [PMID: 28576863 PMCID: PMC5560794 DOI: 10.1534/genetics.117.203232] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/31/2017] [Indexed: 12/15/2022] Open
Abstract
The genetic code converts information from nucleic acid into protein. The genetic code was thought to be immutable, yet many examples in nature indicate that variations to the code provide a selective advantage. We used a sensitive selection system involving suppression of a deleterious allele (tti2-L187P) in Saccharomyces cerevisiae to detect mistranslation and identify mechanisms that allow genetic code evolution. Though tRNASer containing a proline anticodon (UGG) is toxic, using our selection system we identified four tRNASerUGG variants, each with a single mutation, that mistranslate at a tolerable level. Mistranslating tRNALeuUGG variants were also obtained, demonstrating the generality of the approach. We characterized two of the tRNASerUGG variants. One contained a G26A mutation, which reduced cell growth to 70% of the wild-type rate, induced a heat shock response, and was lost in the absence of selection. The reduced toxicity of tRNASerUGG-G26A is likely through increased turnover of the tRNA, as lack of methylation at G26 leads to degradation via the rapid tRNA decay pathway. The second tRNASerUGG variant, with a G9A mutation, had minimal effect on cell growth, was relatively stable in cells, and gave rise to less of a heat shock response. In vitro, the G9A mutation decreases aminoacylation and affects folding of the tRNA. Notably, the G26A and G9A mutations were phenotypically neutral in the context of an otherwise wild-type tRNASer These experiments reveal a model for genetic code evolution in which tRNA anticodon mutations and mistranslation evolve through phenotypically ambivalent intermediates that reduce tRNA function.
Collapse
|
35
|
Kollmar M, Mühlhausen S. Nuclear codon reassignments in the genomics era and mechanisms behind their evolution. Bioessays 2017; 39. [PMID: 28318058 DOI: 10.1002/bies.201600221] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The canonical genetic code ubiquitously translates nucleotide into peptide sequence with several alterations known in viruses, bacteria, mitochondria, plastids, and single-celled eukaryotes. A new hypothesis to explain genetic code changes, termed tRNA loss driven codon reassignment, has been proposed recently when the polyphyly of the yeast codon reassignment events has been uncovered. According to this hypothesis, the driving force for genetic code changes are tRNA or translation termination factor loss-of-function mutations or loss-of-gene events. The free codon can subsequently be captured by all tRNAs that have an appropriately mutated anticodon and are efficiently charged. Thus, codon capture most likely happens by near-cognate tRNAs and tRNAs whose anticodons are not part of the recognition sites of the respective aminoacyl-tRNA-synthetases. This hypothesis comprehensively explains the CTG codon translation as alanine in Pachysolen yeast together with the long known translation of the same codon as serine in Candida albicans and related species, and can also be applied to most other known reassignments.
Collapse
Affiliation(s)
- Martin Kollmar
- Group Systems Biology of Motor Proteins, Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stefanie Mühlhausen
- Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| |
Collapse
|
36
|
Lin X, Yu ACS, Chan TF. Efforts and Challenges in Engineering the Genetic Code. Life (Basel) 2017; 7:life7010012. [PMID: 28335420 PMCID: PMC5370412 DOI: 10.3390/life7010012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 12/15/2022] Open
Abstract
This year marks the 48th anniversary of Francis Crick’s seminal work on the origin of the genetic code, in which he first proposed the “frozen accident” hypothesis to describe evolutionary selection against changes to the genetic code that cause devastating global proteome modification. However, numerous efforts have demonstrated the viability of both natural and artificial genetic code variations. Recent advances in genetic engineering allow the creation of synthetic organisms that incorporate noncanonical, or even unnatural, amino acids into the proteome. Currently, successful genetic code engineering is mainly achieved by creating orthogonal aminoacyl-tRNA/synthetase pairs to repurpose stop and rare codons or to induce quadruplet codons. In this review, we summarize the current progress in genetic code engineering and discuss the challenges, current understanding, and future perspectives regarding genetic code modification.
Collapse
Affiliation(s)
- Xiao Lin
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, NT, Hong Kong, China.
| | - Allen Chi Shing Yu
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, NT, Hong Kong, China.
| | - Ting Fung Chan
- School of Life Sciences, The Chinese University of Hong Kong, Sha Tin, NT, Hong Kong, China.
| |
Collapse
|
37
|
Kollmar M, Mühlhausen S. How tRNAs dictate nuclear codon reassignments: Only a few can capture non-cognate codons. RNA Biol 2017; 14:293-299. [PMID: 28095181 DOI: 10.1080/15476286.2017.1279785] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
mRNA decoding by tRNAs and tRNA charging by aminoacyl-tRNA synthetases are biochemically separated processes that nevertheless in general involve the same nucleotides. The combination of charging and decoding determines the genetic code. Codon reassignment happens when a differently charged tRNA replaces a former cognate tRNA. The recent discovery of the polyphyly of the yeast CUG sense codon reassignment challenged previous mechanistic considerations and led to the proposal of the so-called tRNA loss driven codon reassignment hypothesis. Accordingly, codon capture is caused by loss of a tRNA or by mutations in the translation termination factor, subsequent reduction of the codon frequency through reduced translation fidelity and final appearance of a new cognate tRNA. Critical for codon capture are sequence and structure of the new tRNA, which must be compatible with recognition regions of aminoacyl-tRNA synthetases. The proposed hypothesis applies to all reported nuclear and organellar codon reassignments.
Collapse
Affiliation(s)
- Martin Kollmar
- a Group Systems Biology of Motor Proteins , Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry , Göttingen , Germany
| | - Stefanie Mühlhausen
- b Milner Centre for Evolution, Department of Biology and Biochemistry , University of Bath, Milner Centre for Evolution , Bath , UK
| |
Collapse
|
38
|
|
39
|
Ostrov N, Landon M, Guell M, Kuznetsov G, Teramoto J, Cervantes N, Zhou M, Singh K, Napolitano MG, Moosburner M, Shrock E, Pruitt BW, Conway N, Goodman DB, Gardner CL, Tyree G, Gonzales A, Wanner BL, Norville JE, Lajoie MJ, Church GM. Design, synthesis, and testing toward a 57-codon genome. Science 2016; 353:819-22. [PMID: 27540174 DOI: 10.1126/science.aaf3639] [Citation(s) in RCA: 192] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 07/21/2016] [Indexed: 01/07/2023]
Abstract
Recoding--the repurposing of genetic codons--is a powerful strategy for enhancing genomes with functions not commonly found in nature. Here, we report computational design, synthesis, and progress toward assembly of a 3.97-megabase, 57-codon Escherichia coli genome in which all 62,214 instances of seven codons were replaced with synonymous alternatives across all protein-coding genes. We have validated 63% of recoded genes by individually testing 55 segments of 50 kilobases each. We observed that 91% of tested essential genes retained functionality with limited fitness effect. We demonstrate identification and correction of lethal design exceptions, only 13 of which were found in 2229 genes. This work underscores the feasibility of rewriting genomes and establishes a framework for large-scale design, assembly, troubleshooting, and phenotypic analysis of synthetic organisms.
Collapse
Affiliation(s)
- Nili Ostrov
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Matthieu Landon
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Program in Systems Biology, Harvard University, Cambridge, MA 02138, USA. Ecole des Mines de Paris, Mines Paristech, Paris 75272, France
| | - Marc Guell
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Gleb Kuznetsov
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Program in Biophysics, Harvard University, Boston, MA 02115, USA
| | - Jun Teramoto
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Natalie Cervantes
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Minerva Zhou
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kerry Singh
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Michael G Napolitano
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Program in Biological and Biomedical Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Mark Moosburner
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Ellen Shrock
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Benjamin W Pruitt
- Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Nicholas Conway
- Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Daniel B Goodman
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA
| | - Cameron L Gardner
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Gary Tyree
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | - Barry L Wanner
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Julie E Norville
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Marc J Lajoie
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA. Wyss Institute for Biologically Inspired Engineering, Boston, MA 02115, USA.
| |
Collapse
|
40
|
Smith DR. The mutational hazard hypothesis of organelle genome evolution: 10 years on. Mol Ecol 2016; 25:3769-75. [PMID: 27357487 DOI: 10.1111/mec.13742] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/14/2016] [Accepted: 06/22/2016] [Indexed: 12/12/2022]
Abstract
Why is there such a large variation in size and noncoding DNA content among organelle genomes? One explanation is that this genomic variation results from differences in the rates of organelle mutation and random genetic drift, as opposed to being the direct product of natural selection. Along these lines, the mutational hazard hypothesis (MHH) holds that 'excess' DNA is a mutational liability (because it increases the potential for harmful mutations) and, thus, has a greater tendency to accumulate in an organelle system with a low mutation rate as opposed to one with a high rate of mutation. Various studies have explored this hypothesis and, more generally, the relationship between organelle genome architecture and the mode and efficiency of organelle DNA repair. Although some of these investigations are in agreement with the MHH, others have contradicted it; nevertheless, they support a central role of mutation, DNA maintenance pathways and random genetic drift in fashioning organelle chromosomes. Arguably, one of the most important contributions of the MHH is that it has sparked crucial, widespread discussions about the importance of nonadaptive processes in genome evolution.
Collapse
Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada
| |
Collapse
|
41
|
Swart EC, Serra V, Petroni G, Nowacki M. Genetic Codes with No Dedicated Stop Codon: Context-Dependent Translation Termination. Cell 2016; 166:691-702. [PMID: 27426948 PMCID: PMC4967479 DOI: 10.1016/j.cell.2016.06.020] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 04/19/2016] [Accepted: 06/06/2016] [Indexed: 01/13/2023]
Abstract
The prevailing view of the nuclear genetic code is that it is largely frozen and unambiguous. Flexibility in the nuclear genetic code has been demonstrated in ciliates that reassign standard stop codons to amino acids, resulting in seven variant genetic codes, including three previously undescribed ones reported here. Surprisingly, in two of these species, we find efficient translation of all 64 codons as standard amino acids and recognition of either one or all three stop codons. How, therefore, does the translation machinery interpret a “stop” codon? We provide evidence, based on ribosomal profiling and “stop” codon depletion shortly before coding sequence ends, that mRNA 3′ ends may contribute to distinguishing stop from sense in a context-dependent manner. We further propose that such context-dependent termination/readthrough suppression near transcript ends enables genetic code evolution. Alternative nuclear genetic codes continue to be discovered in ciliates Genetic codes with stops and all their codons encoding standard amino acids exist Transcript ends may distinguish stop codons as such in ambiguous genetic codes The ability to resolve genetic code ambiguity may enable genetic code evolution
Collapse
Affiliation(s)
| | - Valentina Serra
- Department of Biology, University of Pisa, Pisa 56126, Italy
| | - Giulio Petroni
- Department of Biology, University of Pisa, Pisa 56126, Italy
| | - Mariusz Nowacki
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland.
| |
Collapse
|
42
|
Smith DR, Keeling PJ. Protists and the Wild, Wild West of Gene Expression: New Frontiers, Lawlessness, and Misfits. Annu Rev Microbiol 2016; 70:161-78. [PMID: 27359218 DOI: 10.1146/annurev-micro-102215-095448] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The DNA double helix has been called one of life's most elegant structures, largely because of its universality, simplicity, and symmetry. The expression of information encoded within DNA, however, can be far from simple or symmetric and is sometimes surprisingly variable, convoluted, and wantonly inefficient. Although exceptions to the rules exist in certain model systems, the true extent to which life has stretched the limits of gene expression is made clear by nonmodel systems, particularly protists (microbial eukaryotes). The nuclear and organelle genomes of protists are subject to the most tangled forms of gene expression yet identified. The complicated and extravagant picture of the underlying genetics of eukaryotic microbial life changes how we think about the flow of genetic information and the evolutionary processes shaping it. Here, we discuss the origins, diversity, and growing interest in noncanonical protist gene expression and its relationship to genomic architecture.
Collapse
Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, Ontario, Canada N6A 5B7;
| | - Patrick J Keeling
- Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4;
| |
Collapse
|
43
|
Wei Y, Wang J, Xia X. Coevolution between Stop Codon Usage and Release Factors in Bacterial Species. Mol Biol Evol 2016; 33:2357-67. [PMID: 27297468 PMCID: PMC4989110 DOI: 10.1093/molbev/msw107] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Three stop codons in bacteria represent different translation termination signals, and their usage is expected to depend on their differences in translation termination efficiency, mutation bias, and relative abundance of release factors (RF1 decoding UAA and UAG, and RF2 decoding UAA and UGA). In 14 bacterial species (covering Proteobacteria, Firmicutes, Cyanobacteria, Actinobacteria and Spirochetes) with cellular RF1 and RF2 quantified, UAA is consistently over-represented in highly expressed genes (HEGs) relative to lowly expressed genes (LEGs), whereas UGA usage is the opposite even in species where RF2 is far more abundant than RF1. UGA usage relative to UAG increases significantly with PRF2 [=RF2/(RF1 + RF2)] as expected from adaptation between stop codons and their decoders. PRF2 is > 0.5 over a wide range of AT content (measured by PAT3 as the proportion of AT at third codon sites), but decreases rapidly toward zero at the high range of PAT3. This explains why bacterial lineages with high PAT3 often have UGA reassigned because of low RF2. There is no indication that UAG is a minor stop codon in bacteria as claimed in a recent publication. The claim is invalid because of the failure to apply the two key criteria in identifying a minor codon: (1) it is least preferred by HEGs (or most preferred by LEGs) and (2) it corresponds to the least abundant decoder. Our results suggest a more plausible explanation for why UAA usage increases, and UGA usage decreases, with PAT3, but UAG usage remains low over the entire PAT3 range.
Collapse
Affiliation(s)
- Yulong Wei
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Juan Wang
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Xuhua Xia
- Department of Biology, University of Ottawa, Ottawa, ON, Canada Ottawa Institute of Systems Biology, Ottawa, ON, Canada
| |
Collapse
|
44
|
Hammerling MJ, Gollihar J, Mortensen C, Alnahhas RN, Ellington AD, Barrick JE. Expanded Genetic Codes Create New Mutational Routes to Rifampicin Resistance inEscherichia coli. Mol Biol Evol 2016; 33:2054-63. [DOI: 10.1093/molbev/msw094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
45
|
Mühlhausen S, Findeisen P, Plessmann U, Urlaub H, Kollmar M. A novel nuclear genetic code alteration in yeasts and the evolution of codon reassignment in eukaryotes. Genome Res 2016; 26:945-55. [PMID: 27197221 PMCID: PMC4937558 DOI: 10.1101/gr.200931.115] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 04/28/2016] [Indexed: 01/12/2023]
Abstract
The genetic code is the cellular translation table for the conversion of nucleotide sequences into amino acid sequences. Changes to the meaning of sense codons would introduce errors into almost every translated message and are expected to be highly detrimental. However, reassignment of single or multiple codons in mitochondria and nuclear genomes, although extremely rare, demonstrates that the code can evolve. Several models for the mechanism of alteration of nuclear genetic codes have been proposed (including “codon capture,” “genome streamlining,” and “ambiguous intermediate” theories), but with little resolution. Here, we report a novel sense codon reassignment in Pachysolen tannophilus, a yeast related to the Pichiaceae. By generating proteomics data and using tRNA sequence comparisons, we show that Pachysolen translates CUG codons as alanine and not as the more usual leucine. The Pachysolen tRNACAG is an anticodon-mutated tRNAAla containing all major alanine tRNA recognition sites. The polyphyly of the CUG-decoding tRNAs in yeasts is best explained by a tRNA loss driven codon reassignment mechanism. Loss of the CUG-tRNA in the ancient yeast is followed by gradual decrease of respective codons and subsequent codon capture by tRNAs whose anticodon is not part of the aminoacyl-tRNA synthetase recognition region. Our hypothesis applies to all nuclear genetic code alterations and provides several testable predictions. We anticipate more codon reassignments to be uncovered in existing and upcoming genome projects.
Collapse
Affiliation(s)
- Stefanie Mühlhausen
- Group Systems Biology of Motor Proteins, Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Peggy Findeisen
- Group Systems Biology of Motor Proteins, Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Uwe Plessmann
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany; Bioanalytics Group, Department of Clinical Chemistry, University Medical Center Göttingen, 37075 Göttingen, Germany
| | - Martin Kollmar
- Group Systems Biology of Motor Proteins, Department of NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| |
Collapse
|
46
|
Bezerra AR, Guimarães AR, Santos MAS. Non-Standard Genetic Codes Define New Concepts for Protein Engineering. Life (Basel) 2015; 5:1610-28. [PMID: 26569314 PMCID: PMC4695839 DOI: 10.3390/life5041610] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/12/2015] [Accepted: 10/21/2015] [Indexed: 11/16/2022] Open
Abstract
The essential feature of the genetic code is the strict one-to-one correspondence between codons and amino acids. The canonical code consists of three stop codons and 61 sense codons that encode 20% of the amino acid repertoire observed in nature. It was originally designated as immutable and universal due to its conservation in most organisms, but sequencing of genes from the human mitochondrial genomes revealed deviations in codon assignments. Since then, alternative codes have been reported in both nuclear and mitochondrial genomes and genetic code engineering has become an important research field. Here, we review the most recent concepts arising from the study of natural non-standard genetic codes with special emphasis on codon re-assignment strategies that are relevant to engineering genetic code in the laboratory. Recent tools for synthetic biology and current attempts to engineer new codes for incorporation of non-standard amino acids are also reviewed in this article.
Collapse
Affiliation(s)
- Ana R Bezerra
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
| | - Ana R Guimarães
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
| | - Manuel A S Santos
- Health Sciences Department, Institute for Biomedicine-iBiMED, University of Aveiro, Campus de Santiago, Aveiro 3810-193, Portugal.
| |
Collapse
|
47
|
Baranov PV, Atkins JF, Yordanova MM. Augmented genetic decoding: global, local and temporal alterations of decoding processes and codon meaning. Nat Rev Genet 2015; 16:517-29. [PMID: 26260261 DOI: 10.1038/nrg3963] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The non-universality of the genetic code is now widely appreciated. Codes differ between organisms, and certain genes are known to alter the decoding rules in a site-specific manner. Recently discovered examples of decoding plasticity are particularly spectacular. These examples include organisms and organelles with disruptions of triplet continuity during the translation of many genes, viruses that alter the entire genetic code of their hosts and organisms that adjust their genetic code in response to changing environments. In this Review, we outline various modes of alternative genetic decoding and expand existing terminology to accommodate recently discovered manifestations of this seemingly sophisticated phenomenon.
Collapse
Affiliation(s)
- Pavel V Baranov
- School of Biochemistry and Cell Biology, University College Cork, Ireland
| | - John F Atkins
- 1] School of Biochemistry and Cell Biology, University College Cork, Ireland. [2] Department of Human Genetics, University of Utah, 15 N 2030 E Rm. 7410, Salt Lake City, Utah 84112-5330, USA
| | | |
Collapse
|
48
|
Mukai T, Yamaguchi A, Ohtake K, Takahashi M, Hayashi A, Iraha F, Kira S, Yanagisawa T, Yokoyama S, Hoshi H, Kobayashi T, Sakamoto K. Reassignment of a rare sense codon to a non-canonical amino acid in Escherichia coli. Nucleic Acids Res 2015; 43:8111-22. [PMID: 26240376 PMCID: PMC4652775 DOI: 10.1093/nar/gkv787] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/22/2015] [Indexed: 11/13/2022] Open
Abstract
The immutability of the genetic code has been challenged with the successful reassignment of the UAG stop codon to non-natural amino acids in Escherichia coli. In the present study, we demonstrated the in vivo reassignment of the AGG sense codon from arginine to L-homoarginine. As the first step, we engineered a novel variant of the archaeal pyrrolysyl-tRNA synthetase (PylRS) able to recognize L-homoarginine and L-N(6)-(1-iminoethyl)lysine (L-NIL). When this PylRS variant or HarRS was expressed in E. coli, together with the AGG-reading tRNA(Pyl) CCU molecule, these arginine analogs were efficiently incorporated into proteins in response to AGG. Next, some or all of the AGG codons in the essential genes were eliminated by their synonymous replacements with other arginine codons, whereas the majority of the AGG codons remained in the genome. The bacterial host's ability to translate AGG into arginine was then restricted in a temperature-dependent manner. The temperature sensitivity caused by this restriction was rescued by the translation of AGG to L-homoarginine or L-NIL. The assignment of AGG to L-homoarginine in the cells was confirmed by mass spectrometric analyses. The results showed the feasibility of breaking the degeneracy of sense codons to enhance the amino-acid diversity in the genetic code.
Collapse
Affiliation(s)
- Takahito Mukai
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Atsushi Yamaguchi
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Kazumasa Ohtake
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Mihoko Takahashi
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Akiko Hayashi
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Fumie Iraha
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Satoshi Kira
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Tatsuo Yanagisawa
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Shigeyuki Yokoyama
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Hiroko Hoshi
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Takatsugu Kobayashi
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Kensaku Sakamoto
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| |
Collapse
|
49
|
Brandão MM, Spoladore L, Faria LCB, Rocha ASL, Silva-Filho MC, Palazzo R. Ancient DNA sequence revealed by error-correcting codes. Sci Rep 2015; 5:12051. [PMID: 26159228 PMCID: PMC4498232 DOI: 10.1038/srep12051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 06/16/2015] [Indexed: 11/09/2022] Open
Abstract
A previously described DNA sequence generator algorithm (DNA-SGA) using error-correcting codes has been employed as a computational tool to address the evolutionary pathway of the genetic code. The code-generated sequence alignment demonstrated that a residue mutation revealed by the code can be found in the same position in sequences of distantly related taxa. Furthermore, the code-generated sequences do not promote amino acid changes in the deviant genomes through codon reassignment. A Bayesian evolutionary analysis of both code-generated and homologous sequences of the Arabidopsis thaliana malate dehydrogenase gene indicates an approximately 1 MYA divergence time from the MDH code-generated sequence node to its paralogous sequences. The DNA-SGA helps to determine the plesiomorphic state of DNA sequences because a single nucleotide alteration often occurs in distantly related taxa and can be found in the alternative codon patterns of noncanonical genetic codes. As a consequence, the algorithm may reveal an earlier stage of the evolution of the standard code.
Collapse
Affiliation(s)
- Marcelo M Brandão
- 1] Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas, SP, Brazil [2] Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13400-918, Piracicaba, SP, Brazil
| | - Larissa Spoladore
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13400-918, Piracicaba, SP, Brazil
| | - Luzinete C B Faria
- Departamento de Telemática, Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, 13081-970, Campinas, SP, Brazil
| | - Andréa S L Rocha
- Departamento de Telemática, Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, 13081-970, Campinas, SP, Brazil
| | - Marcio C Silva-Filho
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13400-918, Piracicaba, SP, Brazil
| | - Reginaldo Palazzo
- Departamento de Telemática, Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, 13081-970, Campinas, SP, Brazil
| |
Collapse
|
50
|
Pathways of Genetic Code Evolution in Ancient and Modern Organisms. J Mol Evol 2015; 80:229-43. [DOI: 10.1007/s00239-015-9686-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/03/2015] [Indexed: 10/23/2022]
|