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Updated: Jun 3, 2026
09:08
Generation and Assembly of Virus-Specific Nucleocapsids of the Respiratory Syncytial Virus
Published on: July 27, 2021
Nidovirus ribonucleases: Structures and functions in viral replication
1Centre for Infection and Immunity, The Queen's University of Belfast, Belfast, UK.
RNA Biology
|March 23, 2011
Summary
Nidoviruses utilize unique nucleases, including uridylate-specific endoribonuclease (NendoU) and exoribonuclease (ExoN), for RNA replication. ExoN may enhance viral genome fidelity, enabling larger RNA genomes in these viruses.
Area of Science:
- Virology
- Molecular Biology
- Structural Biology
Background:
- Nidoviruses possess exceptionally large RNA genomes, necessitating unique replication and expression strategies.
- These viruses encode a diverse array of enzymes for RNA synthesis, modification, and processing.
Purpose of the Study:
- To review recent advancements in the structural and functional characterization of nidovirus nuclease activities.
- To highlight the roles of conserved nidovirus nucleases, NendoU and ExoN, in viral RNA metabolism.
Main Methods:
- Structural and functional analyses of nidovirus-specific nucleases.
- Comparative genomics to assess enzyme conservation across nidovirus families.
Main Results:
- Nidoviruses encode a uridylate-specific endoribonuclease (NendoU) and a 3'-to-5' exoribonuclease (ExoN).
- ExoN, related to the DEDD superfamily, is conserved in nidoviruses with large genomes (~30 kb).
- Evidence suggests ExoN contributes to reduced mutation rates and enhanced fidelity during viral RNA replication.
Conclusions:
- ExoN may be a critical factor enabling the expansion of nidovirus genome sizes.
- Understanding these nucleases provides insights into the evolution and replication of large RNA viruses.
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