The Spanning Tree Model and the Assembly Kinetics of RNA Viruses

TL;DR

This paper presents a statistical physics analysis of a model explaining how small ssRNA viruses selectively assemble their capsids around viral RNA in cells, accounting for observed assembly behaviors.

Contribution

It introduces a detailed kinetic and equilibrium analysis of a simple model for selective nucleation in ssRNA virus assembly, linking theory with experimental observations.

Findings

Model explains preferential nucleation on viral RNA

Analysis aligns with experimental assembly observations

Provides insights into virus assembly mechanisms

Abstract

Single-stranded (ss) RNA viruses self-assemble spontaneously in solutions that contain the viral RNA genome molecules and the viral capsid proteins. The self-assembly of empty capsids can be understood on the basis of free energy minimization of rather simple models. However, during the self-assembly of complete viral particles in the cytoplasm of an infected cell, the viral genome molecules must be selected from a large pool of very similar host messenger RNA molecules. It is known that the assembly process takes the form of preferential heterogeneous nucleation of capsid proteins on viral RNA molecules ("selective nucleation"). Recently, a simple mathematical model was proposed for the selective nucleation of small ssRNA viruses. In this paper we present a statistical physics analysis of the thermal equilibrium and kinetic properties of that model and show that it can account, at least qualitatively, for numerous observations of the self-assembly of small ssRNA viruses.