A comparison of the polypeptides of human and bovine respiratory syncytial viruses and murine pneumonia virus

Human and bovine respiratory syncytial (RS) viruses and pneumonia virus of mice (PVM) are morphologically similar viruses and are the only known members of the metamyxovirus (or pneumovirus) group. Comparison of the polypeptides of these viruses by polyacrylamide-gel electrophoresis (PAGE) has shown that the serologically related human and. bovine RS viruses have similar polypeptide profiles. However, PVM does not resemble the other two viruses closely. The molecular weights of RS virus polypeptides were established by discontinuous SDS-PAGE in gradient slab gels and were comparable to previous determinations by continuous SDS-PAGE (Wunner and Pringle, 1976), apart from the detection of an additional 10,000-MW polypeptide. Comparison of 11 strains of human RS virus isolated from different localities, or from the same locality at different dates, showed that the relative mobility of VP32 (a nonglycosylated polypeptide of unknown function) was a stable characteristic of each strain. The mobilities of the other viral polypeptides showed little variation. The 11 strains fell into three groups in which the molecular weights of VP32 were estimated to be 31,000, 32,000, and 35,000, but there was no clear correlation with date or place of origin.