FIG. 2.
Essential regions of the IL-6 3′UTR that induce rapid mRNA degradation. (A) The human wild-type IL-6 3′UTR behind the GFP cDNA was shortened by various deletions, and the effect on mRNA stability was assessed in stably transfected COS-7 cells. Cytoplasmic mRNA was isolated at different time points after actinomycin D (Act D) treatment and probed for GFP and GAPDH mRNA by Northern hybridization as described for Fig. 1. The graphic also indicates the positions of AUUUA sequences with ARE-like properties in human IL-6 mRNA. T1/2, half-life. (B) mRNA half-lives were calculated from typical decay curves by linear regression between 0 and 120 min. Values ± SD are based on at least two independent experiments.