Changes in protein and nucleic acid metabolism in baby hamster kidney cells infected with foot-and-mouth disease virus

Summary

At a multiplicity of infection by foot-and-mouth disease virus sufficient to induce maximum changes in host cell metabolism, baby hamster kidney cells showed a decreased turnover of protein, RNA and DNA. Up to 50% inhibition of protein synthesis occurred by 90 minutes postinfection, when viral-induced synthesis of RNA polymerase had not yet started. Viral inhibition of protein synthesis was not decreased by guanidine at a concentration which inhibited production of viral-specific RNA polymerase. At 300 minutes postinfection, when virus production had reached its maximum, 70 to 90% of cellular protein synthesis had stopped. The relative ease of obtaining this value and its reproducibility at various time intervals make it a useful experimental reference parameter. Deoxyribonucleic acid synthesis was unchanged and RNA synthesis was only decreased 10 to 20% at 90 minutes. At 300 minutes, the respective maximum decreases were 90 and 55%. Analyses of RNA profiles from pulse labeled cells indicated, however, that ribosomal RNA synthesis was more strongly reduced at 300 minutes in infected cells than the 55% average value would indicate. The 45 S peak, present in uninfected cells and postulated to be a precursor of ribosomal RNA, was missing. Cells infected 300 minutes possessed a new 37 S RNA peak which probably represented viral RNA.