CONICET | Buscador de Institutos y Recursos Humanos

Mapping of the Z-binding and oligomerization regions within the Tacaribe Virus Nucleoprotein. Levingston Mac leod J. M.1, Casabona J. C. 1, Gómez G. 2, y López N. 1 1CEVAN-ICT Milstein CONICET. Bs As. 2CIQUIBIC- Universidad Nac. de Córdoba. Córdoba. Argentina. Arenaviruses, such as Tacaribe virus (TacV) and its closely related pathogenic Junin virus (JunV), are enveloped viruses with a bipartite negative-sense RNA genome which encodes the nucleocapsid protein (N), the precursor of the envelope glycoprotein complex (GP), the polymerase (L) and a RING finger protein (Z), that is the driving force of arenavirus budding. We have established a plasmid-based system which allowed the successful packaging of TacV-like nucleocapsids along with Z and GP of JunV into infectious virus-like particles (VLPs). Using this system, we have demonstrated that Z-N interactions are required for assembly of the nucleocapsids into arenavirus particles. To identify the region(s) on the N molecule involved in the interaction with Z, N mutants carrying either C-terminal, N-terminal or site-directed mutations were analyzed for their ability to form a complex with Z, as detected by coimmunoprecipitation. The assembly of mutant N proteins into the VLPs was also analized by Western blot. We found that the 210-residues C-terminal region of N, which comprises a putative Zinc finger motif, is required for both N-Z interactions and the incorporation of N into VLPs. Our findings also indicated that the N-terminus of N (residues 1 to 332), which is dispensable for the incorporation of N into VLPs, is involved in N-N interactions.