CUTTING EDGE - A NEWLY IDENTIFIED RESPONSE ELEMENT IN THE CD95 LIGANDPROMOTER CONTRIBUTES TO OPTIMAL INDUCIBILITY IN ACTIVATED T-LYMPHOCYTES

Inducible expression of CD95 ligand on activated T lymphocytes contrib utes to both cytotoxic effector mechanisms and peripheral T cell homeo stasis, To understand better the transcriptional events that regulate this expression, we have examined the CD95 ligand promoter to determin e which regions are required for its induced activity following T cell stimulation. We report here the identification of a new response elem ent within the promoter that is required for its optimal function in a ctivated Jurkat T cells. This region is bound by proteins contained in nuclear extracts of activated, but not resting, T cells. Multimerizat ion of this sequence independently drives transcription in response to T cell activation, while mutation of it substantially decreases induc ible promoter activity. Finally, we pro,ide evidence that T cell activ ation-induced transcription of the CD95 ligand gene is regulated coord inately by this response element together with two previously defined sites for nuclear factor of activated T cells (NFAT).