A NUCLEAR FACTOR OF ACTIVATED T-CELL-LIKE TRANSCRIPTION FACTOR IN MAST-CELLS IS INVOLVED IN IL-5 GENE-REGULATION AFTER IGE PLUS ANTIGEN STIMULATION

IL-5, which is produced mainly by activated T cells and allergically t riggered mast cells, is a major survival and differentiation factor fo r eosinophils, and therefore, is of relevance to diseases associated w ith this type of cell infiltration, most importantly asthma. In this s tudy, we have examined the transcriptional regulation of human IL-5 in a mouse mast cell line, CPII, stimulated with IgE and Ag. We report t hat an inducible activity in the region between -177 and -80, and a co nstitutive activity between -80 and -70, in the promoter of the human gene, are both necessary for the allergically triggered activation. A computer-assisted search for transcription factor binding motifs revea led a nuclear factor of activated T cell (NF-AT) and a GATA consensus site in the two regions. Corresponding binding activities were detecte d to be present in nuclear extracts from the mouse mast cell line by d efined NF-AT and GATA binding sites as probes for a gel shift analysis . Competition analysis, in combination with probes from the human IL-5 promoter, confirmed that these factors indeed bind to the consensus s equences identified by computer analysis. An oligonucleotide spanning the IL-5 NF-AT consensus site is shown to confer allergic stimulation to a basal IL-5 promoter only in conjunction with the CATA site downst ream, indicating that an inducible NF-AT-like factor cooperates with a constitutive member of the GATA transcription Factor family in mediat ing the allergic stimulation of the human IL-5 gene.