Chromosomal proteins of mouse teratocarcinoma cells.

We have analyzed chromosomal proteins extracted from murine teratocarcinoma-derived stem cell lines (F9 and 12-1) and from their differentiated derivatives (12-1a) because of the differential sensitivity to DNase I digestion of these two cell types. The chromosomal DNA of stem cells is more sensitive to DNase I digestion than that of differentiated cells. Stem cell core histones are more highly acetylated than their differentiated counterparts, and certain high-mobility group (HMG) proteins from stem cells (HMG 1 and HMG 2) are found in greater amounts than in the differentiated cells though others (HMG 14 and HMG 17) occur in similar amounts. We have also identified a new HMG protein (HMG 9) that is present in stem cells and is lost following differentiation.