MORPHOMETRIC AND FUNCTIONAL-STUDY OF APOPTOTIC CELL CHROMATIN

Apoptosis is usually characterized by profound morphological nuclear c hanges. Chromatin undergoes a progressive condensation that eventually involves all the nucleus, At earlier stages chromatin appears as divi ded in compact and diffuse areas, while the nuclear pores disappear fr om the nuclear envelope that surrounds the compact areas, and cluster around diffuse chromatin. Here we have performed a morphometric study on the different chromatin areas of freeze-fractured apoptotic cell nu clei in order to investigate its morphometric and functional organizat ion. We have found large portions of inactive chromatin aggregations c orresponding to the dense cap-shaped patches, while domains of nucleos omic fibres have been identified in the diffuse chromatin areas. The c orrelation of the nucleosomic fibre/diffuse chromatin domain with the nuclear pore clusters is demonstrated, and its implications with a pos sible residual nuclear activity are discussed.