An Unprecedented Non-canonical Nuclear Genetic Code with All Three Termination Codons Reassigned as Sense Codons

0507432 - BC 2020 RIV GB eng J - Journal Article
Záhonová, K. - Kostygov, A.Y. - Ševčíková, T. - Yurchenko, Vyacheslav - Eliáš, M.
An Unprecedented Non-canonical Nuclear Genetic Code with All Three Termination Codons Reassigned as Sense Codons.
Current Biology. Roč. 26, č. 17 (2016), s. 2364-2369. ISSN 0960-9822. E-ISSN 1879-0445
R&D Projects: GA ČR(CZ) GA16-18699S
Institutional support: RVO:60077344
Keywords : stop codon * evolution * trypanosomatids * translation * mechanism * ancient * erf1
OECD category: Cell biology
Impact factor: 8.851, year: 2016
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S0960982216307059?via%3Dihub

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 Glade 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.
Permanent Link: http://hdl.handle.net/11104/0298418