Exon 1 and half of exon 2 were replaced by a DNA cassette containing the Cyr61 promoter, the dm (apoptosis defective mutant allele) open reading frame (containing the signal sequence, IGFBP, VWC, variable, TSP and CT domains with H1 and H2 sites of Cyr61) and a neo cassette. The dm open reading frame is defective in apoptotic synergism with TNFalpha. The absence of protein product was confirmed by western blot analysis following serum-stimulation.