ABSTRACT
This chapter reviews some of the recent work on the changes of nonhistone chromosomal proteins and chromatin structures in differentiating erythroid cells and in rat colon and liver during chemical carcinogenesis. Programmed, spatiotemporal expression of cellular genes forms the basis for differentiation and organogenesis in higher eukaryotes. The chapter examines the extent of species specificity of nonhistone proteins, as well as specificity for different stages of erythroid cell development. The specificity of chicken erythroid cell chromatin was compared with goose and frog chromatins and mouse erythroleukemia cell chromatin to determine species specificity. Chromatin which contains complexes of DNA, histone, nonhistone proteins, and trace amounts of RNA is the principal site of genetic endowment and its expression in eukaryotic organisms. The nuclear nonhistone protein components of the nuclear antigens are very tightly bound to DNA. These proteins are a heterogeneous group of nonhistone proteins.
