Two Specific Groups of Nhc Proteins Involved in Gene Expression *

This chapter expresses that nonhistone chromatin (NHC) proteins are involved in both gene structure and expression. It provides the initial evidence that chromatin subunits derived from micrococcal nuclease digestion, followed by subsequent sucrose density gradient centrifugation revealed the presence of several groups of NHC proteins. Although a group of NHC proteins associated with the heterogeneous ribonucleoprotein particles (HnRNP) also co-sediments with the chromatin subunit, there remain certain specific NHC proteins in the nucleosomes. In view of recent findings in immunoglobulin genes, oncogenes, and calcitonin gene structure, it has become evident that the DNA sequence by itself can mediate gene expression. The NHC proteins must be involved in designating a special configuration or packaging of the chromatin fiber for differential gene expression. In general, it is important to note that the organization of chromatin in the nucleus of eukaryotes defines the specific gene expression at differential stages of an organism.