Figure 1.
(A) Regulation of IL-6 expression in TC10 cells. After induction for 6 hr with 2,000 units/ml TNF and/or 10−6 M DEX (added at −1 hr), the medium was assayed for IL-6 biological activity. NI, noninduced cell culture. (B) Repression by DEX is independent of new protein synthesis. TC10 cells were noninduced (lane 1), treated with 10−6 M DEX (lanes 2 and 6), or induced for 6 hr with 2,000 units/ml TNF in the absence (lanes 3 and 7) or presence (lanes 4 and 8) of 10−6 M DEX. The same series of treatments was performed in the presence of 25 ng/ml CHX (lanes 5–8). DEX and/or CHX were added, where appropriate, 1 hr before TNF. The respective induction levels were quantified and compared with the mRNA level in the noninduced state, which was arbitrarily set to 1. Rehybridization with a glyceraldehyde-3-phosphate dehydrogenase probe served as a control for equal loading. (C) DEX treatment does not influence the amount of TNF-activated IκB-α mRNA. The filter shown in B was stripped and reprobed with human IκB-α.