Deadenylation and turnover of interferon-beta mRNA

The pathway of degradation of human interferon-beta (IFN-beta) mRNA was examined in murine C127 cells that carry an expression vector for this mRNA. The IFN-beta mRNA decayed with a half-life of approximately 45 min in actinomycin D-treated cells and became gradually shorter. This mRNA was superinduced in cycloheximide-treated cells, but it also became gradually shorter. However, apparently full-length species of IFN-beta mRNA accumulated after prolonged incubation with cycloheximide. The shortened IFN-beta mRNA species were partially deadenylated and less stable than full-length species. These findings suggest that at least two nuclease activities are involved in degrading IFN-beta mRNA; one deadenylates this mRNA and decays in cycloheximide-treated cells, while the other apparently breaks down deadenylated mRNA.