FIG. 7.
Unresponsiveness of the IL-8 ARE to HuR-mediated stabilization and its reversal by auxiliary domains of the GM-CSF ARE or the c-fos ARE. β-Globin mRNAs containing the ARE of IL-8, GM-CSF, or c-fos (A) or the core domain of the IL-8 or GM-CSF ARE 3′ adjacent to a random sequence (R-IL-8CD or R-GMCSFCD, respectively) or chimeric AREs consisting of the core domain of the IL-8 ARE and the auxiliary domain of the GM-CSF or c-fos ARE (GMCSFAD-IL-8CD or fosAD-IL-8CD, respectively) (B) were coexpressed with empty vector or myc-HuR as indicated. (C) Cells were transfected with plasmids encoding the β-globin-fosAD-IL-8CD mRNA and myc-HuR or MKK62E together with empty vector or an expression vector for MK2K76R. mRNA stability was determined and quantified as described in the legend to Fig. 1.