FIG. 1.

The IL-6 3′UTR confers mRNA instability on a stable GFP mRNA. GFP mRNA with or without the 3′UTR of human IL-6 mRNA was stably expressed in COS-7 cells. Transcription was blocked by actinomycin D (Act D). (A) GFP mRNA was measured at different time points on Northern blots by hybridization with a GFP-specific probe and normalized to endogenous GAPDH mRNA. (B) The mRNA decay was plotted on a semilogarithmic scale and the half-life calculated by linear regression. Error bars indicate standard deviations (SD) from at least three independent experiments.