[
Ernst Schering Res Found Workshop,
2000]
The proliferation of cells is an integral part of development and tissue homeostatsis in multicellular animals(reviewed by Raff 1996; Folletee and O'farrel 1997). Two opposing processes, the division of cells on one hand and the programmed death of cells on the other hand, determine the overall rate of cell proliferation, The proper regulation of these two physiological processes is therefore a crucial aspect of development and of tissue homeostatsis(reviewed by Edgar and Lehner 1996; Shrr 1997;Jacobson et al. 1997). While the importance of the process of cell division has long been recognized, the role and extent of programmed cell death, or apoptosis, has only been realized within the last decades (Glucksmann 1950; Kerr et al. 19972). Massive programmed cell death occurs, for instance, during the development of the nervous system and in the immune system: more than 50% on all neurons and oligodendrocytes formed in the periperal and central vertebrate nervous system undergo programmed cell death neurogenesis...