Nuclear apoptotic changes: An overview

Apoptosis is a form of active cell death essential for morphogenesis, devel opment, differentiation, and homeostasis of multicellular organisms. The ac tivation of genetically controlled specific pathways that are highly conser ved during evolution results in the characteristic morphological features o f apoptosis that are mainly evident in the nucleus. These include chromatin condensation, nuclear shrinkage, and the formation of apoptotic bodies. Th e morphological changes are the result of molecular alterations, such as DN A and RNA cleavage, post-translational modifications of nuclear proteins, a nd proteolysis of several polypeptides residing in the nucleus. During the last five years our understanding of the process of apoptosis has dramatica lly increased. However, the mechanisms that lead to apoptotic changes in th e nucleus have been only partially clarified. Here, we shall review the mos t recent findings that may explain why the nucleus displays these striking modifications. Moreover, we shall take into consideration the emerging evid ence about apoptotic events as a trigger for the generation of autoantibodi es to nuclear components. (C) 2001 Wiley-Liss, Inc.