TUMOR-NECROSIS-FACTOR-ALPHA GENE-REGULATION IN ACTIVATED T-CELLS INVOLVES ATF-2 JUN AND NFATP/

The human tumor necrosis fatter alpha (TNF-alpha) gene is one of the e arliest genes expressed upon the activation of a T or B cell through i ts antigen receptor. Previous experiments have demonstrated that in st imulated T cells, a TNF-alpha promoter element, k3, which binds NFATp, is required for the cyclosporin A-sensitive transcriptional activatio n of the gene. Here, we demonstrate that a cyclic AMP response element (CRE), which lies immediately upstream of the k3 site, is also requir ed for induction of TNF-alpha gene transcription in T cells stimulated by calcium ionophore or T-cell receptor ligands. The CRE binds ATF-2 and Jun proteins in association with NFATp bound to k3. These proteins bind noncooperatively in vitro; however, the transcriptional activity of the CRE/k3 composite site is dramatically higher than the activity of the k3 site alone, indicating that the two sites cooperate in vivo . This study is the first demonstration of a role for ATF-2 in TNF-alp ha gene transcription and of a functional interaction between ATF-2/Ju n and NFATp. This novel pairing of NFATp with ATF-2/Jun may account fo r the specific and immediate pattern of TNF-alpha gene transcription i n stimulated T cells.