IGH MINISATELLITE SUPPRESSION OF USF-BINDING-SITE-MEDIATED AND E-MU-MEDIATED TRANSCRIPTIONAL ACTIVATION OF THE ADENOVIRUS MAJOR LATE PROMOTER

The 50bp repeat unit of the minisatellite within the D(H)-J(H) interval of the human immunoglobulin heavy chain locus binds a nuclear factor present in a wide variety of cell types. The binding site contains the myc/HLH motif, CACGTG, and represents a 15 of 17 base match for the USF/MLTF binding site adjacent to the adenovirus major late promoter (MLP). Unlike the USF/MLTF site, the IGH minisatellite possesses no enhancer activity. However, it can significantly suppress, in cis and in trans, USF-site-mediated transcriptional activation of the MLP. In murine myeloma cells, the IGH minisatellite can suppress, in trans, MLP activation by the murine heavy chain gene enhancer, Emu. These activities potentially represent a DNA-based form of squelching.