Figure 1.
Growth in Tc− media induced Flag-ΔN-IκBα expression and inhibited NF-κB activity. (A) F-ΔN-IκBα expression was induced within 1 day after Tc withdrawal. Western blot analysis using M5 mAb. Lanes 1–3, extracts from cells grown in Tc+ media days 1–3; lanes 4–6, extracts from cells grown in Tc− media, days 1–3. (B) EMSA indicated that F-ΔN-IκBα expression inhibited NF-κB activity. Two specific complexes were formed after incubating the extracts from A with a NF-κB probe from the HIV LTR marked κB-1 and κB-2. Lane 1, 100-fold mutant cold competitor. Lane 2, 100-fold excess wild-type cold competitor. Lanes 3–5, extracts from cells grown in Tc+ media, days 1–3; lanes 6–8, extracts from cells grown in Tc− media, days 1–3