Effect of sodium butyrate on messenger RNA populations in myogenic cells in culture.

Sodium butyrate, when added in millimolar concentrations to a culture of myoblasts of the L6 cell line, inhibits reversibly cell proliferation and differentiation. The aim of this work was to study the effect of sodium butyrate on the nuclear and cytoplasmic RNAs in these cells. We have prepared (3H) DNAs complementary to cytoplasmic polyadenylated RNAs from treated and untreated cells and performed homologous and heterologous hybridizations with cytoplasmic polyadenylated RNAs and with total nuclear RNAs. The hybridization kinetics led to the following conclusions: a) Hybridization with nuclear RNAs shows that butyrate allows the transcription of most of the RNA sequences synthesized in proliferating myoblasts, including the sequences that are no longer synthesized in untreated myotubes. However some differences in the hybridization saturation levels indicate that sodium butyrate might modify the expression of a limited number of genes involved in cell proliferation, muscular differentiation, or both. b) Hybridization with cytoplasmic polyadenylated RNAs shows that sodium butyrate acts also at a post-transcriptional level, it produces a large decrease in the frequency of the abundant sequences present in untreated cells, but has little effect on the total number of different RNA species.