Transforming growth factor-beta (TGF-beta) superfamily members constitute a group of multifunctional factors that are able to stimulate apoptotic cell death in a variety of cells. In this report, we show that a zinc-finger transcription factor (TIEG) is an immediate early gene transcriptionally induced by TGF-beta in the epithelial Mv1Lu cell line. We also demonstrate that, mimicking TGF-beta effects, ectopic overexpression of TIEG is sufficient to trigger the apoptotic cell program in these cells, which is preceded by a decrease of Bcl-2 protein levels, Finally, apoptotic events elicited by TIEG overexpression can be effectively prevented by ectopic co-expression of Bcl-2, On the basis of these results we suggest that induction of TIEG expression has a role in the pro-apoptotic properties of TGF-beta. (C) 1999 Federation of European Biochemical Societies.
