Icosahedral Virion Scaffolding Proteins

University Of Arizona, Tucson AZ

Investigators

Abstract

The assembly of proteins and nucleic acids into viruses involves numerous molecular interactions. Often assembly is dependent on scaffolding proteins. Analogous to scaffoldings used in building construction, these proteins assist assembly, but are not found in the final product. The broad objective of this research is to elucidate the molecular mechanisms of scaffolding-mediated viral morphogenesis, using the Microviridae, a family of small single-stranded DNA viruses. The functions of scaffolding protein domains are elucidated with chimeric proteins, constructed between related viruses, or proteins containing a deletion of a specific domain. These altered proteins only perform a subset of the natural functions, thus arresting virion morphogenesis at distinct stages. By analyzing the deleterious effects of these altered proteins and how viruses can mutate to overcome these effects (second-site genetic analyses), a more detailed picture of viral morphogenesis emerges. In addition to scaffolding proteins, protein interactions with single-stranded Microviridae DNA genomes appear to affect the last stage of assembly. A combination of genetic and structural approaches (X-ray crystallography) will be used to further elucidate this relatively new phenomenon. Broader Impact: The project includes the scientific education of graduate and undergraduate students in the Principal Investigator's laboratory. In addition, viral and host cell strains generated as part of the research are used in a large undergraduate Microbiology course, taught by the Principal Investigator, to illustrate the concepts of both classical and molecular genetics.