Diversity and modularity of tyrosine-accepting tRNA-like structures

Area of Science:

• Virology
• Molecular Biology
• Bioinformatics

Background:

• Positive-sense single-stranded RNA viruses possess 3' tRNA-like structures (TLSs) for aminoacylation by host enzymes.
• Tyrosine-accepting TLSs (TLS^Tyr) from different viral families exhibit variations in their structure, particularly in the 5' domain responsible for anticodon mimicry.

Purpose of the Study:

• To investigate the structural and functional differences of TLS^Tyr 5' domains between viruses in the hordeivirus and Bromoviridae families.
• To determine the role of the 5' domain in the aminoacylation efficiency of hordeivirus TLS^Tyr.
• To explore the evolutionary relationships between divergent TLS^Tyr structures.

Main Methods:

• Bioinformatic analysis of viral RNA secondary structures.
• Biochemical assays for in vitro aminoacylation.
• Construction and testing of chimeric RNA molecules.

Main Results:

• A distinct secondary structure for the 5' domain of hordeivirus TLS^Tyr was identified, differing from that in Bromoviridae.
• The 5' domain of hordeivirus TLS^Tyr is essential for efficient in vitro aminoacylation.
• A chimeric TLS^Tyr RNA combining 5' and 3' domains from different viral families was successfully aminoacylated, indicating functional modularity.

Conclusions:

• The structurally distinct 5' domain of hordeivirus TLS^Tyr mimics the anticodon loop, similar to its Bromoviridae counterpart.
• TLS^Tyr elements exhibit modularity, allowing for functional interchangeability between viral families.
• Divergent TLS^Tyr structures offer insights into the evolution of viral RNA elements and their interactions with host factors.