An Investigation of the C-terminal Domain of Human Parvovirus B19’s Non-structural Protein 1

Abstract

Human Parvovirus B19 is a small, single-stranded DNA virus with a wide range of clinical manifestations, some of which remain largely unexplained on a mechanistic level. Non-Structural protein 1 (NS1) is one of the few proteins encoded by the viral genome, and it serves as the main replicative protein. Its three-domain structure gives the protein a wide variety of functions within the viral life cycle, and specifically, the protein has an N-terminus nuclease domain, a central helicase domain, and a C-terminus transactivation domain. The primary activity of NS1 that is explored here is the ability of NS1 to transactivate the single P6 B19V promoter as well as several human promoters. While the 189-long C-terminal domain has been implicated in this transactivation activity, it is not well understood, and very little is known about the mechanism through which NS1 transactivates viral and host promoters. Additionally, protein-protein interactions between NS1 and host proteins have been speculated, but the location, tissue-specificity, and effects of these interactions are not clear. This thesis describes different approaches utilized to better understand the activity of the C-terminal domain and the interactions between NS1 and human proteins. The methods used include, among others, co-immunoprecipitation assays, crosslinking of bacterially expressed proteins, and luciferase assays in a mammalian expression system. While little conclusive data has been obtained, the work described here lays a foundation for further exploration of the C-terminal domain of Non-Structural protein 1.