Mechanisms of programmed cell death in the developing brain.

Programmed cell death (apoptosis) is an important mechanism that determines the size and shape of the vertebrate nervous system. Recent gene-targeting studies have indicated that homologs of the cell-death pathway in the nematode Caenorhabditis elegans have analogous functions in apoptosis in the developing mammalian brain. However, epistatic genetic analysis has revealed that the apoptosis of progenitor cells during early embryonic development and apoptosis of postmitotic neurons at later stage of brain development have distinct roles and mechanisms. These results provide new insight on the significance and mechanism of neural cell death in mammalian brain development.