Constitutive Attachment of Murine Erythroleukemia Cell Histone-Depleted DNA Loops to Nuclear Scaffolding Is Found in the β-Major but Not the α1-Globin Gene

We have identified a region of the β-globin gene that is attached constitutively to histone-depleted murine erythroleukemia cell nuclei. This region spans 800 bp and is located at −300 to −1100 bp upstream from the site of transcriptional initiation. Attachment is not altered by transcriptional activation of the β-globin gene during induction to terminal differentiation, and the same region of the β-globin gene is attached to histone-depleted myeloma cell nuclei (NS-1). The attached region contains an A/T-rich section, in addition to a sequence closely related to the Drosophila topoisomerase II consensus cleavage sequence. No comparable site of attachment of the α1-globin gene was detected when a region spanning 1.5 kb 5′ to 0.5 kb 3′ of the region of transcription was studied.