Identification of regions of bovine respiratory syncytial virus N protein required for binding to P protein and self-assembly.

The interaction of bovine respiratory syncytial virus (BRSV) nucleocapsid protein (N) with itself and phosphoprotein (P) was investigated using the yeast two-hybrid system. N-P interaction was abolished by any of a series of internal deletions or deletions at the C terminus. In contrast, removal of up to 32 amino acids from the N terminus had little effect. Interestingly, while removal of the C-terminal 32 amino acids ablated interaction, it was largely restored by a second deletion removing up to 32 amino acids from the N terminus. Many of these interactions of the BRSV N protein demonstrated a pattern that was similar to those occurring in the N protein of related viruses. N-N interaction was abolished by any of the internal deletions; however, removal of up to 32 amino acids from the N terminus or C terminus was tolerated and increased the strength of the interaction between the two N proteins.