Normal cellular replication of Sendai virus without the trans-frame, nonstructural V protein

The Sendai virus V protein is a nonstructural trans-frame protein in which a highly conserved cys-rich Zn2+-binding domain is fused to the N-terminal half of the P protein via mRNA editing. Using a recently developed system in which infectious virus is recovered from cDNA, we have engineered a virus in which a translation stop codon was placed al the beginning of the V ORF. Translation of the V-stop mRNA yields a W-like protein, i.e., a protein composed of the N-terminal half of the P protein alone which is naturally expressed at low levels from the P gene. This V-minus but W-augmented virus was found to replicate normally in cell culture and embryonated chicken eggs. The Sendai virus V protein is thus an accessory protein, and the cys-rich Zn2+-binding domain is likely to function in a specialized role during virus propagation. (C) 1997 Academic Press.