The mammalian cell nucleus is a membrane-bound organelle that contains the machinery essential for gene expression. Although early studies suggested that little organization exists within this compartment, more contemporary studies have identified an increasing number of specialized domains or subnuclear organelles within the nucleus (Lamond and Earnshaw,1998EF7; Spector,1993EF15). In some cases, these domains have been shown to be dynamic structures and, in addition, rapid protein exchange occurs between many of the domains and the nucleoplasm(Misteli, 2001EF10). An extensive effort is currently underway by numerous laboratories to determine the biological function(s) associated with each domain. The accompanying poster presents an overview of commonly observed nuclear domains.FIG1
The nucleus is bounded by a nuclear envelope, a double-membrane structure, of which the outer membrane is contiguous with the rough endoplasmic reticulum and is often studded with ribosomes. The inner and outer nuclear membranes are fused...
