Structural and antigenic analysis of the nucleoprotein of bovine ephemeral fever rhabdovirus.

The nucleotide sequence of the bovine ephemeral fever virus (BEFV) genome has been determined from the 3' terminus to the end of the nucleoprotein (N) gene. The 3' leader sequence comprises 50 nucleotides and shares a common terminal three nucleotides (3'-UGC-) and a downstream U-rich domain with vesicular stomatitis virus (VSV) and rabies virus. The N gene comprises 1328 nucleotides from the transcription initiation consensus sequence (AACAGG) to the conserved transcription termination-poly(A) sequence [CATG(A)7] and encodes a polypeptide of 431 amino acids with an estimated M(r) of 49,159 and a pI of 5.4. The deduced amino acid sequence of the BEFV N protein is similar to those of other mammalian rhabdoviruses and is more closely related in sequence to vesiculoviruses (VSV Indiana and New Jersey, Piry, Chandipura) than to lyssaviruses (rabies and Mokola). An almost full-length clone, 1301 bp in length, of the BEFV N gene and clones derived from 5'-terminal (559 bp) and 3'-terminal (742 bp) fragments were expressed in Escherichia coli as glutathione-S-transferase fusion proteins. A panel of 12 BEFV N protein-specific monoclonal antibodies was shown to react in immunoblots with fusion proteins containing the almost full-length N protein and the C-terminal fragment, but not the N-terminal fragment. Two of these antibodies also reacted with baculovirus-expressed rabies virus N protein. Polyclonal mouse ascitic fluids derived from BEFV, rabies virus and several other related viruses were also shown to cross-react in immunoblots with purified preparations of rabies virus and BEFV N proteins.