Proteins of transcriptionally active and inactive chromatin from friend erythroleukemia cells

Abstract

Transcriptionally active and inactive chromatin fractions were prepared from control and dimethyl sulfoxide (DMSO)-treated murine erythroleukemia cells by the DNase II technique of Gottesfeld et al. (Proc natl acad sci US 71 (1974) 2193). The active and inactive chromatin fractions from control and DMSO-treated cells had essentially the same total histone content, but the active chromatin fractions from both control and treated cells contained significantly less H1 histone. The amount of non-histone protein was similar in the corresponding chromatin fractions of control and treated cells. For both treated and control cell chromatin, however, the content of non-histone protein was consistently lower in the inactive fraction, P 2, than in the active fraction, S 2. No significant differences were observed between the polyacrylamide gel banding patterns, as determined by Coomassie blue staining, of histone or non-histone chromatin proteins of the corresponding fractions from treated and control cells. However, dual radioisotope labeling studies indicated an increased incorporation of radioactive amino acids into a 50 000 D polypeptide of unfractionated chromatin and a 23 000 D polypeptide of active chromatin (S 2) from DMSO-treated cells.