Nuclear Function and Organization: The Potential of Immunochemical Approaches

Abstract

Publisher Summary This chapter discusses the contributions of immunochemical approaches to the study of nuclear structure and activity. By segregating the nuclear compartment from the cytoplasm, the nuclear envelope represents the most distinctive feature of a eukaryotic cell. It consists of a double membrane enclosing a 20- to 50-nm-wide perinuclear space. The two membranes are frequently joined and penetrated by nuclear pore complexes, that is, elaborate supramolecular assemblies through which most, if not all, macromolecules are exchanged between nucleus and cytoplasm. The outer nuclear membrane is frequently contiguous with the endoplasmic reticulum and studded with ribosomes, while in most cells the inner membrane is closely associated with chromatin. The nuclear lamina is a fibrillar protein meshwork apposed to the nucleoplasmic surface of the inner nuclear membrane. It is presumed to be important for envelope structure and stability; moreover, it may play a role in organizing the spatial arrangement of interphase chromosomes. Immunochemical studies have revealed that gametogenesis and embryonic development of different organisms are accompanied by profound changes in the polypeptide composition of the nuclear lamina. It is possible that these changes might relate to alterations in the functional organization of nuclei in differentiating cells.