TNF synergizes with the lack of p100 in the induction of target gene expression.

(A) Western blot of NF-κB family members in cytoplasmic and nuclear protein extracts (15 µg/sample) from unstimulated (0 h) and TNF-stimulated (6 and 24 h, 20 ng/ml recombinant murine TNF) wild-type and p100^−/− MEFs. As cytoplasmic and nuclear loading controls β-actin and RNA Pol II were assayed, respectively. (B) Changes in mRNA levels of selected genes were analyzed by qRT-PCR. From 16 analyzed genes, 12 responded synergistically to TNF and the lack of p100 whereas only four genes responded similarly to TNF treatment of wild-type (grey squares) and p100^−/− MEFs (black circles; see also Figure S4). qRT-PCR data represent n = 3 independent TNF stimulation experiments and are expressed as mean values ± SD. Differences between wild-type and p100^−/− MEFs at each time-point were analyzed by Welch tests. P≤0.05 was considered significant (*).