Analysis of genetic code ambiguity arising from nematode-specific misacylated tRNAs

Area of Science:

• Molecular Biology
• Genetics
• Proteomics

Background:

• Accurate aminoacylation of transfer RNAs (tRNAs) is essential for faithful genetic code translation.
• Nematode-specific V-arm-containing tRNAs (nev-tRNAs) exhibit in vitro misacylation with leucine, potentially violating the genetic code.
• Major nev-tRNA isotypes, nev-tRNA(Gly) and nev-tRNA(Ile), could theoretically lead to codon ambiguity (GGG and AUA) if misacylated.

Purpose of the Study:

• To investigate the functionality of nev-tRNAs in vivo.
• To assess the impact of nev-tRNAs on the proteome of Caenorhabditis elegans.
• To determine if nematode genetic code translation is ambiguous due to nev-tRNA misacylation.

Main Methods:

• Analysis of nucleotide sequences in the 3' end regions of nev-tRNAs to confirm CCA addition.
• Subcellular localization analysis to confirm nuclear export of nev-tRNAs.
• Whole-cell proteome analysis in C. elegans to detect mistranslation.

Main Results:

• Nev-tRNAs undergo correct maturation, including CCA addition, and are exported from the nucleus.
• Nev-tRNAs are processed into mature forms and are available for translational processes.
• Whole-cell proteome analysis revealed no detectable nev-tRNA-induced mistranslation in C. elegans.

Conclusions:

• Despite possessing misacylation properties, nev-tRNAs do not induce mistranslation in C. elegans under normal conditions.
• The nematode genetic code exhibits strict translational fidelity, contrary to predictions based on in vitro misacylation data.
• Highly conserved deviant tRNAs in nematodes do not compromise the accuracy of protein synthesis.