AP-1 expression in hairy and nonhairy cells.

(A-E) Analysis of AP-1 interaction with Box E in hairy and nonhairy cells. The radiolabeled DNA fragment CD11c Box E containing Box E (Figure 2) was incubated with no nuclear extract (Probe) or 1.3 μg of nuclear extract prepared from the hairy cell lines Mo (A); HK (B); or EH (C); the neoplastic lymphocytes of a patient with HCL (D); or U937 cells treated for 24 hours with PMA (E). Binding reactions were performed in the absence (−) or presence (+) of a 500-fold molar excess of unlabeled probe or double-stranded DNA fragments purchased from Stratagene Cloning Systems that represent consensus binding sites for AP-1 and Sp1. DNA-protein binding reactions were also performed with no competitor after rabbit polyclonal antibodies that specifically interact with c-Jun (cJunαa, cJunαb), JunB (JunBα), JunD (JunDα) or the Fos family (Fosα) were incubated with nuclear extracts. (F) Cellular distribution of AP-1 interaction with Box E. EMSA was performed using the radiolabeled DNA fragment CD11c Box E incubated with no nuclear extract (Probe) or 1.3 μg of nuclear extract prepared from MEG-01 cells induced for 24 hours with PMA; MEG-01 cells untreated with PMA; Mo hairy cells; HK hairy cells; U937 cells induced for 24 hours with PMA; U937 cells untreated with PMA; Jurkat cells induced for 24 hours with PMA; Jurkat cells untreated with PMA; K562; HeLa; or IM-9 cells. Binding reactions were performed either in the absence (−) of unlabeled specific competitor DNA or in the presence (+) of a 500-fold molar excess of unlabeled CD11c Box E.