Analysis of Homotypic and Heterotypic Interactions of Arenavirus Z Matrix Protein

LOUREIRO ME; LEVINGSTON JM; LÓPEZ N

Sevilla, España

Workshop; FEBS Workshop on Understanding Transient Miolecular Interactions in Biology; 2010

FEBS (The Federation of European Biochemical Societies)

Arenaviruses, such as Tacaribe virus (TacV) and its closely related pathogenic Junín 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). 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 of TacV-Z and JunV-Z 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 and crosslinking essays. Our results show that single amino acid changes selectively interfere with Z-Z or Z-L interactions.