The β-globin dominant control region activates homologous and heterologous promoters in a tissue-specific manner

Abstract We have introduced a human β-globin minilocus, containing the recently described dominant control region (DCR), the β-globin or Thy-1 gene, and a thymidine kinase (tk)-neo R gene into erythroid and nonerythroid cells. Analysis of the transcription levels of the genes shows that the DCR directs high levels of human β-globin, Thy-1 and tk-neo expression independent of integration sites in an erythrold-specific manner. The presence of the DNAasel hypersensitive sites at the 5′ end of the locus is required for this effect on the homologous and heterologous gene. An analysis of the DCR chromatin in transfected mouse erythroleukemic cells suggests that the formation of the hypersensitive sites in this region precedes β-globin gene expression.