THE MAMMALIAN TRANSCRIPTIONAL REPRESSOR REP (CBF1) REGULATES INTERLEUKIN-6 GENE-EXPRESSION

The cellular interleukin-6 (IL-6) gene contains a target site for the mammalian transcriptional repressor REP. The target site is contained within the interleukin response element (ILRE), which mediated IL-6 ac tivation by NF-kappa B. In this study, we show by using transient-expr ession assays that REP represses activated transcription from the IL-6 gene. The presence and position of the REP target site are crucial in mediating repression by REP. While REP binds within the ILRE, it does not target NF-kappa B alone; nonetheless, NF-kappa B binding to the I LRE is required for repression. Our results indicate that REP represse s coactivation by NF-kappa B and another cellular transcription factor , C/EBP-beta.