Comparison of the nucleotide sequence of the SH gene and flanking regions of mumps vaccine virus (Urabe strain) grown on different substrates and isolated from vaccinees.

The small hydrophobic (SH) protein gene and flanking regions of the Urabe Am9 vaccine strain of mumps virus were amplified by the polymerase chain reaction and sequenced directly by the dideoxynucleotide chain termination method. The 434 bp sequence was identical for the Urabe strain isolated from vaccines produced by three manufacturers and for virus isolated following post-vaccination parotitis. No changes were detected for coding, non-coding or intergenic regions between virus grown on different substrates. The Urabe virus SH coding region differed from the published sequence for strain SBL-1 by 14.4% at the nucleotide level and 24.6% at the amino acid level. The 5' non-coding SH region was strongly conserved between the two strains (2% different), whereas the other non-coding regions were not.