An Unprecedented Non-canonical Nuclear Genetic Code with All Three Termination Codons Reassigned as Sense Codons
Language English Country England, Great Britain Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
27593378
DOI
10.1016/j.cub.2016.06.064
PII: S0960-9822(16)30705-9
Knihovny.cz E-resources
- Keywords
- Blastocrithidia, evolution, genetic code, phylogeny, protists, translation, trypanosomatids,
- MeSH
- Cell Nucleus genetics MeSH
- Phylogeny MeSH
- Genetic Code genetics MeSH
- Codon chemistry genetics MeSH
- Protozoan Proteins chemistry genetics MeSH
- Amino Acid Sequence MeSH
- Codon, Terminator chemistry genetics MeSH
- Trypanosomatina genetics MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Codon MeSH
- Protozoan Proteins MeSH
- Codon, Terminator MeSH
A limited number of non-canonical genetic codes have been described in eukaryotic nuclear genomes. Most involve reassignment of one or two termination codons as sense ones [1-4], but no code variant is known that would have reassigned all three termination codons. Here, we describe such a variant that we discovered in a clade of trypanosomatids comprising nominal Blastocrithidia species. In these protists, UGA has been reassigned to encode tryptophan, while UAG and UAA (UAR) have become glutamate encoding. Strikingly, UAA and, less frequently, UAG also serve as bona fide termination codons. The release factor eRF1 in Blastocrithidia contains a substitution of a conserved serine residue predicted to decrease its affinity to UGA, which explains why this triplet can be read as a sense codon. However, the molecular basis for the dual interpretation of UAR codons remains elusive. Our findings expand the limits of comprehension of one of the fundamental processes in molecular biology.
References provided by Crossref.org
Multiple and frequent trypanosomatid co-infections of insects: the Cuban case study
Cysteine tRNA acts as a stop codon readthrough-inducing tRNA in the human HEK293T cell line
Stops making sense - For the people?
Short tRNA anticodon stem and mutant eRF1 allow stop codon reassignment
Comparative Analysis of Three Trypanosomatid Catalases of Different Origin
Genomics of Trypanosomatidae: Where We Stand and What Needs to Be Done?
Diverse telomeres in trypanosomatids
Euglenozoa: taxonomy, diversity and ecology, symbioses and viruses
Analysis of Stop Codons within Prokaryotic Protein-Coding Genes Suggests Frequent Readthrough Events
Evolution and Unprecedented Variants of the Mitochondrial Genetic Code in a Lineage of Green Algae
