“…DNA sequences recognized by these factors are found within the 300 base pairs preceding the IL-2 gene transcription start site. There are minimally five factors, uniquely defined by nucleotide sequence recognition, essential for (ionomycin+PMA)-induced transcription from the IL-2 gene promoter: NF-AT, which binds the IL-2E element (Durand et al, 1988), NF-xB, which binds the IL-2C element (Baumann et al, 1991;Briegel et al, 1991;Hoyos et al, 1989;Shibuya et al, 1989), which recognizes a sequence within the IL-2B element (Jain et al, 1992a,b;Northrop et al, 1992), and OAP (Ullman et al, 1991) and Oct-I (Kamps et al, 1990), which function together, each recognizing an independent sequence within the IL-2A element (Durand et al, 1988 (Mattila et al, 1990). (ii) An NF-xB-dependent enhancer is responsive to PMA, unresponsive to ionomycin, but very responsive to ionomycin in the presence of PMA.…”