ABSTRACT
The core cell death components that control apoptosis in mammalian cells are homologues of the cell death genes (ced genes) originally identified through genetic analysis in the nematode Caenorhabditis elegans (Figure 1.1). The ced-3 gene of C. elegans is homologous to the family of mammalian caspase genes, the ced-9 gene is homologous to the anti-apoptotic members of the Bcl-2 family, and the mammalian apaf-1 gene shares homology with ced-4 (reviewed in Ashkenazi and Dixit, 1998: Green and Reed, 1998; Thornberry and Lazebnik, 1998; Adams and Cory, 1998). More recently, the EGL-1 protein of C. elegans has been shown to have structural homology to the family of pro-apoptotic BH3-only proteins (Conradt and Horvitz, 1998). While these genes code for proteins that constitute the core apoptotic machinery in the cell, many other proteins can regulate the activity of these core components. Thus in cells, the levels of expression of both core and regulatory proteins determine the cellular susceptibility to apoptosis.
