Changes in histone acetylation during the development of rabbit bone marrow erythroid cells

The acetylation of histones in rabbit bone marrow erythroid cells was investigated by measuring the incorporation of labelled acetate into erythroblasts which were separated by velocity sedimentation at unit gravity into five fractions corresponding to different stages of development. Histone acetylation decreased during erythroid development in concert with a decline in DNA and histone synthesis. Some acetylation persisted after condensation of the nucleus and cessation of DNA synthesis in late orthochromatic cells. This residual acetylation may be related to the low level of transcription which is still present at this stage. Sodium butyrate increased the acetylation of histones 2- to 7-fold, with the greatest stimulation occurring in the most immature cells. The general decline in acetylation of histones during erythroid cell development was similar in the presence and absence of butyrate.