J 2023

Short tRNA anticodon stem and mutant eRF1 allow stop codon reassignment

KACHALE, Ambar, Zuzana PAVLIKOVA, Anna NENAROKOVA, Adriana ROITHOVA, Ignacio M DURANTE et. al.

Basic information

Original name

Short tRNA anticodon stem and mutant eRF1 allow stop codon reassignment

Authors

KACHALE, Ambar, Zuzana PAVLIKOVA, Anna NENAROKOVA, Adriana ROITHOVA, Ignacio M DURANTE, Petra MILETINOVA, Kristina ZAHONOVA, Serafim NENAROKOV, Jan VOTYPKA, Eva HORAKOVA, Robert L ROSS, Vyacheslav YURCHENKO, Petra BEZNOSKOVA, Zdenek PARIS, Leos Shivaya VALASEK and Julius LUKES (guarantor)

Edition

Nature, BERLIN, NATURE PORTFOLIO, 2023, 0028-0836

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10600 1.6 Biological sciences

Country of publisher

Germany

Confidentiality degree

není předmětem státního či obchodního tajemství

References:

Impact factor

Impact factor: 64.800 in 2022

RIV identification code

RIV/00216224:90242/23:00133749

UT WoS

000913868600006

Keywords in English

Cognate tRNAs; stop codons; Trypanosoma brucei; Saccharomyces cerevisiae; Condylostoma magnum

Tags

International impact, Reviewed
Změněno: 11/4/2024 23:23, Mgr. Michal Petr

Abstract

V originále

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 principle(1-4). 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 tRNAs(Glu) 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 tRNA(CCA)(Trp) from five to four base pairs (bp). The canonical 5-bp tRNA(Trp) 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.

Links

90242, large research infrastructures
Name: CIISB III