RNA Origami: Packaging a Segmented Genome in Orbivirus Assembly and Replication.

Area of Science:

• Virology
• Molecular Biology
• Structural Biology

Background:

• Bluetongue virus (BTV), an Orbivirus in the Reoviridae family, is a significant livestock pathogen with a 10-segment double-strand RNA (dsRNA) genome.
• Understanding the precise mechanism of genome segment packaging into viral capsids is crucial for viral replication and has remained a challenge.

Purpose of the Study:

• To elucidate the genome packaging mechanism of Bluetongue virus (BTV).
• To detail the roles of untranslated regions (UTRs), intersegmental interactions, and capsid proteins in dsRNA virus genome assembly.

Main Methods:

• Utilized reverse genetics, cell-free RNA packaging assays, and bioinformatics approaches.
• Investigated RNA-RNA interactions, segment conformation, and recruitment into assembling capsids.

Main Results:

• Untranslated regions (UTRs) dictate segment conformation for RNA-RNA interactions.
• A specific order of intersegment interactions forms a network for sorting and packaging.
• Networked segments are recruited into nascent viral capsids.
• Certain capsid proteins may play a role in the packaging process.

Conclusions:

• The study reveals a novel mechanism for dsRNA genome packaging in BTV.
• Identified key steps involving RNA conformation, network formation, and capsid recruitment.
• Findings offer potential avenues for therapeutic interventions against BTV and related viruses.