The functional interaction between HMGA1 and the estrogen receptor requires either the N- or the C-terminal domain of the receptor

We have previously shown that HMGA1 enhances the transcriptional activity of promoters containing the estrogen response element (ERE) and increases binding of the estrogen receptor (ER) to ERE. Herein, we have assessed the transcriptional activity and ERE-binding ability of deleted ER fragments in absence or in presence of HMGA1. The HMGA1 protein stimulated binding and transcriptional activity by a factor of about 2-fold compared to the wild-type ER and both the Nand C-terminal ER deleted domains, but had no effect when both domains were deleted. These data show that HMGA1 cooperates with either the N- or the C-terminal transcriptional activation domain of the ER. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.