DEFINITION OF CIS-REGULATORY ELEMENTS OF THE MOUSE INTERLEUKIN-5 GENEPROMOTER - INVOLVEMENT OF NUCLEAR FACTOR OF ACTIVATED T-CELL-RELATED FACTORS IN INTERLEUKIN-5 EXPRESSION

We have previously reported that the promoter region of the mouse inte rleukin-5 (IL-5) gene, extending from a nucleotide position about -1,2 00 to +33 relative to the transcription initiation site, can mediate t ranscriptional stimulation by phorbol 12-myristate 13-acetate and dibu tyryl cAMP (Bt(2)cAMP) in mouse thymoma EL-4 cells. Here, we describe identification of four cis-regulatory elements necessary for full acti vity of the IL-5 promoter, using deletion and mutation analyses. We de signated these elements as IL-5A (-948 similar to -933), IL-5P (-117 s imilar to -92), IL-5C (-74 similar to -56), and IL-5CLEO (-55 similar to -38). We found that IL-5P bears homology to the binding site for th e nuclear factor of activated T cells (NF-AT) and interacted with prot ein factors in nuclear extracts prepared from EL-4 cells stimulated wi th phorbol 12-myristate 13-acetate and Bt(2)cAMP (designated NFIL-5P). NFIL-5P complex was inhibited in the presence of an excess NF-AT and AP1 oligonucleotides and supershifted by antisera raised against NF-AT p, c-Fos, and c-Jun. It thus seems likely that an NF-AT-related factor is involved in the regulation of IL-5 gene transcription.