Bcl-3 expression in GM-CSF–stimulated and Epo-stimulated TF-1 cells. Whole cell lysates were prepared from growth factor-induced TF-1 cells at the time points indicated. Thirty micrograms of protein was loaded on each lane of a 12% polyacrylamide gel (Bcl-3) or 15 μg of protein was loaded on each lane of a 10% polyacrylamide gel (IκB). The membranes were blotted with anti–Bcl-3 (1:200) or anti-IκB (1:2,000) antibody as a control and then detected with ECL. N.D. indicates time points that were not done. Three independent experiments showed induction of Bcl-3 expression.