Tacaribe virus Z protein residues involved in Z-Z interactions and viral RNA synthesis inhibition

LOUREIRO ME; LEVINGSTON JM; WILDA M; LÓPEZ N

Tucumán, Argentina

Congreso; XLV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2009

SAIB

The arenavirus Tacaribe (TacV) comprises a single phylogenetic lineage together with the four South American pathogenic producers of severe hemorrhagic disease. TacV genome encodes four proteins: the nucleoprotein (N), the glycoprotein precursor, the polymerase (L), and a RING finger protein (Z). TacV-Z is a multifunctional protein that has a key role on virus morphogenesis. In addition, Z is able to self-associate, and exhibits an inhibitory effect on viral RNA replication and transcription through its interaction with the L polymerase (J.Virol. 77:10383-93, 2003). We have previously shown that the region comprised between the residues G36 and R85 of Z is sufficient to maintain Z-L interactions and Z inhibitory functions. To learn more about the roles of individual amino acids in the different interactions of Z, a panel of point mutants was created by in vitro mutagenesis. The interaction between Z mutants and L protein was analyzed by a coimmunoprecipitation assay and a minireplicon system was used to examine the effect of mutations on viral RNA synthesis. The capacity of Z mutants to self-associate was also evaluated by coinmunoprecipitation. Our results show that single amino acid changes selectively interfere with Z-Z or Z-L interactions.