Nucleotide sequence analysis of a matrix and small hydrophobic protein dicistronic mRNA of bovine respiratory syncytial virus demonstrates extensive sequence divergence of the small hydrophobic protein from that of human respiratory syncytial virus.

The nucleotide and deduced amino acid sequences of the matrix (M) and small hydrophobic (SH) proteins of bovine respiratory syncytial virus (BRSV) have been determined from a dicistronic mRNA. Comparison of these sequences with the corresponding published sequences of human respiratory syncytial virus (HRSV) revealed extensive overall homology at both the nucleotide and amino acid levels in the M protein, but low overall homology at both the nucleotide and amino acid levels in the SH protein. There was only 16 to 22% identity between the BRSV SH protein and the HRSV SH proteins at the C terminus. There were also an additional eight amino acids at the C terminus of BRSV. Despite the low level of identity, there were similarities in the predicted hydropathy profiles of BRSV and HRSV SH proteins. The transcription start and stop signals, which are conserved among HRSV mRNAs, were also identified in the M-SH dicistronic mRNA of BRSV. In addition, the intergenic sequence for the M-SH gene junction of BRSV was determined.