DNA and histone synthesis in butyrate-inhibited BSC-1 cells infected with SV40

The effect of butyrate on DNA synthesis, histone synthesis, and virus production in SV40-infected monkey cells has been studied. When cells in which DNA and histone synthesis have been blocked by treatment with butyrate are infected with SV40, DNA synthesis is induced to a level at least equal to that in untreated infected cells. Both viral and cellular DNA sequences are replicated. Viral DNA synthesized is predominantly SV40 Form I. The amount of viral DNA which accumulates is reduced by 10-fold in the presence of butyrate, and the yield of infectious virus is lowered 100-fold. Histone synthesis in these cells is stimulated concomitantly with DNA synthesis. The hyperacetylation of histones characteristic of butyrate-treated cells is unchanged by SV40 infection; the newly synthesized histones are hyperacetylated. Thus the mechanism by which butyrate blocks DNA and histone synthesis is not directly related to the hyperacetylation of histones.