Nucleus

The interchromatin (interchromosomal) compartment is best viewed as a series of channels in and around the individual chromosomal territories that are in direct connection with the nuclear pores of the nuclear envelope. It is filled with nucleoplasm containing subnuclear bodies, nuclear proteins, Figure 4. The double-layered nuclear envelope is studded with nuclear pores, composed of numerous sub-units and related structures. and RNAs, which move rapidly through its channels. It is thought that as RNA is transcribed from genes along the periphery of the chromosomal territory, it drops into the interchromatin compartment for processing, packaging, and transport out of the nucleus through the nuclear pores.

Hormone receptors, histones, and DNA repair enzymes are all known to move actively through these channels, seeking their nuclear targets. Trafficking of molecules is highly efficient; it takes only seconds for a newly synthesized RNA particle to exit through a nuclear pore. Thus the nucleus is a very busy place, with a rapid and continuous exchange of proteins involved in nuclear function and genomic expression occurring both between nuclear compartments and deep within individual compartments, through which access is guaranteed by transportation through the interchromatin compartment.