ABSTRACT
In order for the cell to utilize the biological information contained within its genome, groups of genes, each gene representing a single unit of information, have to be expressed in a coordinated manner. This coordinated gene expression determines the makeup of the transcriptome, which in turn specifies the nature of the proteome and defines the activities that the cell is able to carry out. The internal architecture of the nucleus was first examined by light and electron microscopy. Using conventional techniques, the inside of the nucleus appears to be relatively unstructured, made up of lighter and darker regions with just one distinct feature, the nucleolus, which is the center for synthesis and processing of rRNA molecules, and which appears as a dark area when nuclei are observed with the electron microscope. Chromosome territories appear to be fairly static within an individual nucleus.
