IEX-1L, AN APOPTOSIS INHIBITOR INVOLVED IN NF-KAPPA-B-MEDIATED CELL-SURVIVAL

Transcription factors of the nuclear factor-kappa B/rel (NF-kappa B) f amily may be important in cell survival by regulating unidentified, an ti-apoptotic genes. One such gene that protects cells from apoptosis i nduced by pas or tumor necrosis factor type or (TNF), IEX-1L, is descr ibed here. Its transcription induced by TNF was decreased in cells wit h defective NF-kappa B activation, rendering them sensitive to TNF-ind uced apoptosis, which was abolished by transfection with IEX-1L. In su pport, overexpression of antisense IEX-1L partially blocked TNF-induce d expression of IEX-1L and sensitized normal cells to killing. This st udy demonstrates a key role of IEX-1L in cellular resistance to TNF-in duced apoptosis.