A N-terminal coiled coil motif is essential for Tacaribe Virus Nucleoprotein functionality.

D´ANTUONO AL; LEVINGSTON JM; LOUREIRO ME; LÓPEZ N

Puerto Madryn, Argentina.

Congreso; XLVI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

SAIB

Arenaviruses,such as Tacaribe virus (TCRV) are enveloped viruses with a negative-sense RNA genome, which encodes four proteins:the viral RNA polymerase (L protein), a matrix protein (Z), the precursor (GPC) of the envelope glycoproteins and the nucleocapsid protein (N).The N protein tightly binds to genomic and antigenomic RNAs forming nucleocapsids, which act as templates for both transcription and replication of viral genomes mediated by the virus polymerase.Besides, the ability of N to take part in multiple protein-protein interactions may be important in several steps of the viral life cycle. We have shown that the N-terminal region of N is responsible for homotypic N-N interactions.Here, we have defined a newly recognized coiled coil motif domain as being essential for N self-interactions. Key hydrophobic amino acids within the putative coiled coil motif, were replaced by the polar amino acid Glutamine. The ability of point mutants to self-interact was evaluated by coimmunoprecipitation and their capacity to support viral RNA synthesis was assessed using a TCRV minireplicon system. The relevance of the coiled coil motif in the interaction between N and the L polymerase will be discussed. It is concluded that residues 92-119 of the TCRV N protein may fold as a coiled coil, which is crucial for N to sustain N-N interactions as well as for its role in viral genome replication.