Genetic analysis of programmed cell death in C. elegans has led to the identification of two genes,
ced-9, a cell death suppressor, and
ced-3, a cell death inducer, that play critical roles in regulating programmed cell death. The
ced-9 and
ced-3 genes were found to encode proteins that share structural and functional similarities with the mammalian proto-oncogene product Bcl-2 and interleukin-1 beta converting enzyme (ICE), respectively. Multiple members of the Bcl-2 family and the ICE family have been identified in vertebrates. These results suggest that the mechanism of apoptosis in vertebrates may be evolved from a much simpler version of a similar pathway in primitive organisms.