Biochemistry, Department of


Document Type


Date of this Version

September 2001


Published in SCIENCE VOL 293 28 SEPTEMBER 2001. Copyright 2001. Used by permission.


Methylation of histones at specific residues plays an important role in transcriptional regulation. Chromatin immunoprecipitation of dimethylated lysine 9 on histone H3 across 53 kilobases of the chicken β-globin locus during erythropoiesis shows an almost complete anticorrelation between regions of elevated lysine 9 methylation and acetylation. Lysine 9 is methylated most over constitutive condensed chromatin and developmentally inactive globin genes. In contrast, lysine 4 methylation of histone H3 correlates with H3 acetylation. These results lead us to propose a mechanism by which the insulator in the β-globin locus can protect the globin genes from being silenced by adjacent condensed chromatin.