Alpha-interferon inhibits the expression of heavy chain mu messenger RNA in Daudi cells.

AUTOR(ES)
RESUMO

A clone of Daudi cells (Daudi-S) synthesizes the heavy chain of IgM (mu-chain) under routine conditions of cell culture. In the presence of alpha-interferon, however, synthesis of mu-chain is decreased rapidly at a time when the overall protein synthesis is not modified and the dsRNA-dependent protein kinase and the 2-5A synthetase are induced. This inhibition of mu-chain synthesis seems to be correlated with the antiproliferative action of interferon since it occurs only slightly in another clone of Daudi cells resistant (Daudi-R) to the antiproliferative action of interferon. In these resistant cells, however, the protein kinase and the 2-5A synthetase are induced by interferon. Specific inhibition of mu-chain synthesis in interferon-treated Daudi-S cells is a consequence of decreased steady-state levels of mu-chain mRNA. This effect occurs 4-8 h after addition of interferon in parallel with decreased levels of c-myc mRNA and enhanced levels of HLA mRNA. Reduced levels of mu-chain mRNA in interferon-treated Daudi-S cells is not a consequence of its enhanced degradation as shown by actinomycin D chase experiments. Furthermore, nuclear run on experiments rule out an effect on the transcription of mu-chain mRNA. Therefore, the inhibitory mechanism mediated by interferon might be at the level of termination and/or post-transcriptional processing of mu-chain RNA. In contrast, in these same interferon-treated Daudi-S cells, the inhibition of c-myc gene expression is due to an enhanced degradation of its mRNA (in accord with other reports). These data indicate that interferon can inhibit gene expression by different mechanisms.

ACESSO AO ARTIGO

Documentos Relacionados