IGH minisatellite suppression of USF-binding-site- and E mu-mediated transcriptional activation of the adenovirus major late promoter.

The 50bp repeat unit of the minisatellite within the DH-JH 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, E mu. These activities potentially represent a DNA-based form of squelching.