Fig. 2. ced-3 is transcribed in many cells during developmental periods of cell death. Top and bottom panels for each image are DIC+fluorescence and fluorescence-alone images, respectively. (A) Image of a smg-1(r861) embryo expressing a transgene consisting of the full rescuing (7.6 kb) ced-3 genomic locus, into which GFP with a nuclear localization signal near the start codon was inserted (see Materials and methods). (B) Same as A. Notice cell corpse (circled) weakly expressing GFP. (C) A smg-1(r861) larva containing the same transgene as in A. Notice the absence of GFP expression. The observed fluorescence is caused by autofluorescence from gut granules. (D) A smg-1(r861) L4 male larva containing the same transgene as in A. Notice the bright expression in several cells in the tail. None of these cells is fated to die. (E) A smg-1(r861); ced-3(n717) larva containing the same transgene as in A. Notice the GFP expression in the tail-spike cell (arrows).