Salt extraction of chromatin from normal diploid and SV-40 transformed human fibroblasts

Regulation of cell proliferation is a complex but exceedingly interesting form of gene expression. Overwhelming evidence in the past ten years has shown that the flow of cells through the cell cycle, and the regulation of cell population density, are under the control of the eukaryotic genome. Changes in the function and structure of chromatin have been reported when G0 cells are stimulated to proliferate and when continuously dividing cells move through the different phases of the cell cycle from G1 to S, G2 and mitosis. The changes occurring in the structure and function of chromatin seem to be related to changes occurring in the chromosomal proteins, especially non-histone chromosomal proteins and chromatin-bound protein kinases. Studies are now in progress to isolate the genes, with their respective proteins, that regulate the different steps of the cell cycle.