Sequence variability of the glycoprotein gene of bovine respiratory syncytial virus.

Sequence variation in the attachment glycoprotein G of bovine respiratory syncytial virus (BRSV) was determined. The nucleotide sequences of the G mRNAs of the A51908, VC464 and FS-1 strains of BRSV were compared with the published sequence of the BRSV strain 391-2. Nucleotide sequence alignment showed that overall they are highly conserved, with 90 to 97% identity. In addition, the coding region of strain A51908 was longer by 18 nucleotides at the 3' end. An 84 to 95% level of identity was observed among the deduced amino acid sequences of the G proteins of BRSV strains. A maximum divergence of 19% was found when the extracellular domains of the G proteins were compared. The level of diversity would be consistent, by analogy to the human respiratory syncytial viruses, with these BRSV strains forming a single subgroup.