Analysis of apoptosis induced by TNF-α. Treatment of HEK-293 cells carrying the GFP gene alone (A) with TNF-α in the presence of cycloheximide demonstrates induction of transcription of the PAI-2 gene but only the presence of the 47-kDa protein product. Treatment of cells expressing ZNF198/FGFR1 (FUS), which express both cytoplasmic forms of PAI-2 endogenously, with TNF-α has only a marginal effect on RNA and protein levels of PAI-2. When nucleosome laddering, an indicator of apoptosis, is analyzed in the same cells (B) it can be seen that TNF-α induces apoptosis in cells expressing GFP or the exogenous ZNF198 gene (ZNF), but not in cells expressing the ZNF198/FGFR1 gene (FUS). Similarly, BaF/3 cells (C) expressing the fusion kinase are resistant to TNF-α-induced apoptosis compared with the parental cells which are susceptible.