Overexpression of c‐Myc Inhibits the Appearance of a Specific DNase I Hypersensitive Site in the β‐Globin Chromatin in Murine Erythroleukemia Cells

To investigate the molecular mechanism of regulation of differentiation by c‐Myc, we examined the acquisition of DNase I hypersensitivity by;β‐globin chromatin in an MEL cell transformant (38–2) in which the c‐myc gene was placed under the control of a metallothionein gene promoter. Of the three DNase I hypersensitive sites around the β‐globin gene which were detected in MEL cells after DMSO treatment, the appearance of a specific DNase I hypersensitive site near the promoter was greatly reduced by the Overexpression of c‐Myc. This result suggests that c‐Myc regulates β‐globin expression by interfering with the establishment of an active chromatin conformation around the β‐globin gene.