IER3 functions in the protection of cells from Fas- or tumor necrosis factor type alpha-induced apoptosis. Partially degraded and unspliced transcripts are found after virus infection in vitro, but these transcripts are not found in vivo and do not generate a valid protein. Recombinant human IER3 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.