Program in Neuroscience, Harvard Medical School, Boston, MA 02115.
Mutations in the gene ced-4 block almost all of the programmed cell deaths that normally occur during Caenorhabditis elegans development. We have cloned the ced-4 gene using a ced-4 mutation caused by the insertion of the transposon Tc4. When microinjected into a ced-4 animal, a 4.4 kb DNA fragment derived from the wild-type strain and corresponding to the region of the Tc4 insertion in the mutant ced-4(n1416) rescues the Ced-4 mutant phenotype. The ced-4 gene encodes a 2.2 kb RNA transcript. This mRNA is expressed primarily during embryogenesis, when most programmed cell deaths occur. The Ced-4 protein, as deduced from cDNA and genomic DNA clones, is 549 amino acids in length. Two regions of the putative Ced-4 protein product show some similarity to known calcium-binding domains.