MCB 9723752 Mark Young (Montana State University) The Chemical Basis of Viral Assembly and Disassembly ABSTRACT 1. Technical This study uses the cowpea chlorotic mottle virus (CCMV), a member of the bromovirus group of the Bromoviridea family, as a unique model system to determine the detailed chemical role protein-protein and protein-RNA interactions play in the assembly, maturation, and disassembly processes of a virus. An icosahedral virus, CCMV is constituted by a four component positive sense stranded RNA genome and capsids containing 180 identical coat protein subunits, each of 19.8KD. The specific objectives of this proposal are to: (1) Determine the critical viral RNA-coat protein and coat protein-coat interactions that act as molecular determinants regulating virion architecture and stability; and (2) Determine the ability of the N-terminus of the coat protein to undergo a structural transition from the interior of the virion to the exterior of the virion in order to form a channel for the passage of virion RNA during disassembly. The experimental approach combines molecular and structural tools. Genetic mutations with altered virion architecture and stability are generated and examined for their effect on virion assembly and disassembly in vitro and in vivo, so that critical components can be identified. The results of this research will have significant implications for a broad range of animal, plant, and insect viruses and should provide the basis for strategies for preventing viral infections. 2. Non-technical Understanding the chemical basis of protein-protein and protein-nucleic acid interactions is one of the major goals of modern biology. Virion assembly, maturation, and disassembly is particularly suitable for determining the underlying principles of these interactions. The objective of this study is to determine how the detailed molecular interactions occurring during virus assembly and disassembly influence and regulate virus infectivity. The spherical , cowpea chlorotic mottle virus is the subject of this research project. Biochemical and structural approaches to the analysis of genetic mutants are used to identify the critical components. The findings should contribute to the basic knowledge of how viruses are formed and disrupted, and provide essential information for the design of strategies to prevent viral infection to plants and animals.
