FIGURE 1. Regulation of TNF mRNA stability by p38 MAPK requires TTP.

Wild-type (A) or TTP^−/− (B) BMDM were left untreated or treated with LPS (10 ng ml⁻¹) for 4h and then actinomycin D (10 μg ml⁻¹) was added together with SB 202190 (final concentration 1 μM) or vehicle (0.1% DMSO). Cells were harvested at the times shown and RNA was extracted and northern blotted with an antisense riboprobe to TNF 3’UTR. Graphs show mean TNF mRNA in wild-type (C) or TTP^−/− cells (D) normalised to GAPDH mRNA expressed as a percentage of t=0 actinomycin D treatment ± S.E.M. from three independent experiments. Where not shown error bars are smaller than the symbols. Significance of the effect of SB 202190 was measured by paired Student’s t-test *p<0.01.