[Release of proteins from metaphase chromosomes induced by lipid membranes]

The interaction of the isolated chromosomes with the model phospholipid membranes in the presence of divalent cations leads to chromosomal decondensation as we showed previously by using different methods. In this manuscript we report data concerning the mechanism of such membrane-promoted decondensation. Under the action of liposomes at least three proteins are released from the chromosomes. The appearance of these chromosomal proteins was detected by SDS-electrophoresis of the fraction of the liposomes after dissociation of the complexes. One of these proteins with MW 33 kDa is tightly bound with the liposomes while the other two with MW 25 and 68 kDa release without binding. We suggested that the chromosomal decondensation at mitosis is caused by the action of the newly formed nuclear envelope, in particular by its membrane part which is able to provide the release of chromosomal proteins responsible for keeping the chromosomes in the compact state.