Induction of AP-1 transcription factor components during T-cell activation by interleukin 1 and phorbol esters.

We have examined the effect of interleukin 1 (IL-1) and phorbol esters [12-O-tetradecanoylphorbol-13-acetate (TPA)] on the expression of various components of the AP-1 transcription factor complex during T-cell activation. We previously found that a chloramphenicol acetyltransferase reporter gene driven by the collagenase TPA responsive element was expressed upon stimulation of T-cells by TPA and that this expression was enhanced when IL-1 was added as a costimulant; IL-1 alone had no effect on TPA responsive element-chloramphenicol acetyltransferase expression. In this study, we have found that stimulation of T-cells by IL-1 and TPA is accompanied by activation of a subset of immediate early genes that comprise the AP-1 transcription factor complex. junB and fosB were rapidly induced following stimulation with TPA. Although the levels of other fos-related mRNAs were also elevated, their maximal induction was delayed by approximately 5 h. IL-1 alone had little or no effect, but enhanced TPA induced transcription and steady-state levels of these mRNAs. The expression of fos and jun during T-cell activation was accompanied by increased specific binding of JunB, FosB, and fos-related antigen containing complexes to the TPA responsive element. These findings indicate that the synergistic effect of IL-1 and TPA on AP-1 mediated gene expression is due, in part, to the ability of IL-1 to enhance the expression of genes encoding specific AP-1 transcription factor components.(ABSTRACT TRUNCATED AT 250 WORDS)