Regulation of TNFα mRNA is independent of PARP-14. (A) TNFα mRNA decay in WT and Parp14^−/− BMDM after LPS-stimulation (1 μg/mL) for 2 hours (n = 6 experiments). TF mRNA half-lives are expressed as mean ± SEM, and analyzed using a 2-tailed Student t test. (B) RT-PCR of TF and TNFα mRNA immunoprecipitated by anti-PARP-14 (P) or anti-TTP (T) antibodies compared with rabbit IgG control (C) from lysates of LPS-stimulated (1 μg/mL for 2 hours) WT, Ttp^−/− (left), or Parp14^−/− (right) BMDM. HPRT acts as a negative control for nonspecific mRNA pull-down. The experiment shows that TNFα mRNA was immunoprecipitated from lysates of LPS-stimulated WT macrophage lysates by anti-TTP, but not by anti-PARP-14 antibodies. Also shown is that TNFα, but not TF mRNA was immunoprecipitated by anti-TTP from Parp14^−/− macrophage lysates. TF mRNA was pulled down by anti-PARP-14 from lysates of LPS-treated WT, but not Ttp^−/− macrophages, and by anti-TTP from lysates of LPS-treated WT, but not Parp14^−/− macrophages. NS, nonsignificant.