Mechanistic Studies on Sindbis Virus Replication

Indiana University, Bloomington IN

Investigators

Abstract

Virus replication is achieved through the precise coordination of a series of macromolecular synthetic events. For plus-strand RNA viruses the temporal regulation of gene expression and genome replication occurs through the action of the viral ribonuclear protein complex (vRNP). The vRNP is assembled around viral RNA and its composition is defined by the recruitment of proteins, both viral and host, to specific RNA elements. Differential availability of proteins and viral RNA elements at particular times during the virus replication cycle can therefore alter the composition of the vRNP and change the function of the complex. Identifying RNA elements required for specific macromolecular synthetic events and the proteins that bind them to form a vRNP are fundamental requirements if we are to understand the regulatory processes necessary for virus replication. This project seeks to understand the regulation of gene expression and genome replication of plus-strand RNA viruses using Sindbis virus (SIN), the type species of the alphavirus genus. During SIN replication the genome is translated giving rise to the non-structural polyprotein. A semi-processed form of this protein is required for the copying (minus-strand synthesis) of the genome from which it was translated. In turn the minus-strand RNA serves as a template for production of progeny genomes, and a subgenomic mRNA synthesized by a complex containing the fully processed non-structural proteins. It is therefore apparent that different vRNP complexes perform each of these processes. The project aims to elucidate the molecular interactions that mediate the transitions in vRNP composition and function These studies will significantly impact the understanding of the molecular mechanisms required for alphavirus replication. Additionally, as plus-strand RNA viruses are united by a common scheme of replication, principles established from these studies will be of more general interest and importance for the study of all plus-strand RNA viruses. The project will provide a forum for the training of undergraduate students, graduate students, and post-doctoral fellows. A number of students from various programs (including Initiative for Maximizing Student Diversity Program and Research Experience for Undergraduates Program) have participated in research in the laboratory and it is fully expected that this participation will continue.