Correlation between histone lysine methylation and developmental changes at the chicken β-globin locus

Methylation of histories at specific residues plays an important role in transcriptional regulation. Chromatin immunoprecipitation of dimethytated lysine 9 on histone H3 across 53 kilobases of the chicken beta -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 beta -globin locus can protect the globin genes from being silenced by adjacent condensed chromatin.