Mapping the domains on the phosphoprotein of bovine respiratory syncytial virus required for N–P and P–L interactions using a minigenome system

Abstract

The interaction of bovine respiratory syncytial virus (BRSV) phosphoprotein (P) with nucleocapsid (N) and large polymerase (L) proteins was investigated using an intracellular BRSV–CAT minigenome replication system. Coimmunoprecipitation assays using P-specific antiserum revealed that the P protein can form complexes with N and L proteins. Deletion mutant analysis of the P protein was performed to identify the regions of P protein that interact with N and L proteins. The results indicate that two independent N-binding sites exist on the P protein: an internal region of 161–180 amino acids and a C-terminal region of 221–241 amino acids. The L-binding site was mapped to a region of P protein encompassing amino acids 121–160. The data suggest that N and L protein binding domains on the P protein do not overlap.