Rat liver chromatin. Distribution of histone and nonhistone proteins in eu- and heterochromatin.

Rat liver chromatin was sheared and separated into template-active (euchromatin) and template-inactive (heterochromatin) fractions by glycerol gradient centrifugation. Chromosomal proteins associated with the chromatin fractions were analyzed by sodium dodecyl sulfate-polyacrylamide-gel electrophoresis. Histone composition did not vary qualitatively, but more histone protein was consistently found associated with the euchromatin fractions. Nonhistone protein banding patterns for these chromatin fractions exhibited marked heterogeneity, with a number of bands unique to either eu- or heterochromatin.