Figure 6. RNA-binding domain of TTP is required for in vitro polyadenylation inhibition in RNA containingARE.

Biotin-labeled (A) GM- CSF-ARE_(A)₂₀, (B) IL-10-ARE_(A)₂₀, and (C) TNFα-ARE_(A)₂₀ RNA were used for the in vitro polyadenylation assay as described in Fig. 5. The WT GST-TTP (lanes 5, 6) or GST-TTPΔ95-158 (lanes 7, 8) were included in the reaction mixtures. After reaction, RNA was separated through 8 M urea/8% (w/v) polyacrylamide gels. Each experiment was repeated three to five times, and a representative example is shown for each experiment. RNA molecular mass standards are shown in the left lane. The poly(A) tail lengths were calculated as described in Fig. 5 and plots of tail length vs. time are shown in the right panels. *, p<0.05; **, p<0.01; ***, p<0.005; ****, p<0.001.