Structural and functional analyses of the bunyavirus ribonucleoprotein complex. (360G-Wellcome-091783_Z_10_Z)

The Bunyaviridae family are a diverse group of over 350 RNA viruses classified into five genera, namely Hantavirus, Orthobunyavirus, Phlebovirus, Nairovirus and Tospovirus. Many bunyaviruses are important pathogens of humans, animals and plants for which preventative or therapeutic treatments are unavailable. Bunyavirus pathogenesis depends on formation of the ribonucleoprotein (RNP) complex, in which the bunyavirus genome is entirely encapsidated by the virus-encoded nucleocapsid protein (N). O nly in the form of the RNP is the genome replicated, transcribed and packaged into new progeny particles. Using Bunyamwera orthobunyavirus and Rift Valley fever phlebovirus, we propose to perform a detailed quantitative analysis of the role of individual N protein amino acids in both gene expression and virus assembly. Critical to these analyses, we have generated the first high-resolution crystal structure of a complete bunyavirus N protein. We will pair this information with findings of our fu nctional analyses to reveal the structure-function relationship of the entire RNP complex for both viruses. Also critically, we will generate infectious viruses incorporating N protein mutations, which will allow us to validate our findings in the context of a live-virus infection, and relate how perturbation of molecular interactions between individual viral components affects the overall viral life-cycle