TRANSCRIPTIONAL REGULATION BY COMPETITION BETWEEN ELP ISOFORMS AND NUCLEAR RECEPTORS

ELF is a transcription factor belonging to the nuclear receptor superf amily, The consensus binding sequence for ELF contains a half site of the nuclear receptor recognition element. We demonstrated previously t hat ELP1, the repressor type isoform of ELF, competes for binding with the retinoic acid receptor and represses retinoic acid-induced transa ctivation. In this study, competitive repression by ELP1 was investiga ted for several other nuclear receptors. As in the case of the retinoi c acid receptor, binding of vitamin D receptor, thyroid hormone recept or, and estrogen receptor could be competed by ELP1, resulting in repr ession of their ligand-dependent transactivation. Interestingly, the a ctivator-type ELF isoforms were capable of repressing retinoic acid-in duced transactivation through binding to the retinoic acid receptor bi nding element, These data suggest that competition for target DNA bind ing is a general mechanism of transcriptional repression by ELF isofor ms. (C) 1997 Academic Press