Developmentally dynamic histone acetylation pattern of a tissue-specific chromatin domain

We have defined the histone acetylation pattern of the endogenous murine be ta -globin domain, which contains the erythroid-specific beta -globin genes . The beta -globin locus control region (LCR) and transcriptionally active promoters were enriched in acetylated histones in fetal liver relative to f etal brain, whereas the inactive promoters were hypoacetylated. In contrast , the LCR and both active and inactive promoters were hyperacetylated in yo lk sac. Hypersensitive site two of the LCR was also hyperacetytated in muri ne embryonic: stem cells, whereas beta -globin promoters were hypoacetylate d. Thus, the acetylation pattern varied at different developmental stages. Histone deacetylase inhibition selectively increased acetylation at a hypoa cetylated promoter in fetal liver, suggesting that active deacetylation con tributes to silencing of promoters. We propose that dynamic histone acetyla tion and deacetylation play an important role in the developmental control of beta -globin gene expression.