Programmed cell death

Programmed cell death (PCD) occurs during development in all the animals st udied so far, but the molecular basis has been recently discovered. Apoptos is is a highly organized and genetically controlled mechanism which helps i n maintaining the homeostasis in multicellular organisms. This paper review s the recent developments in the field of PCD. Emphasis has been laid on th e recent developments in the Caenorhabditis elegans cell death programme. T his process is well characterized by some biochemical and cytological event s. Three key genes in the PCD of C. elegans have been characterized. The ce d-3 and ced-4 genes function in the killing of cells while the ced-9 gene p revents this phenomenon. The ced-9 (cell death suppressor) and ced-3 (cell death inducer) genes encode proteins which share a functional and structura l homology with the mammalian proto-oncogene bcl-2 and interleukin-1 beta c onverting enzyme, respectively. These findings reveal key molecules that co ntrol life and death decisions in vertebrates. Characterization of these ge nes has revealed that the process of PCD is evolutionarily conserved and ha s shed light on the molecular nature of the apoptotic machinery.