Estrogen receptor antibodies: specificity and utility in detection, localization and analyses of estrogen receptor alpha and beta

The role of estrogens in regulating cellular metabolism in many tissues is well documented. Estrogens regulate cellular activity by interacting with s pecific intracellular receptor proteins. Two estrogen receptor (ER) isoform s have been isolated, cloned and characterized. Estrogen receptor alpha (ER alpha) and beta (ER beta) are ligand dependent transcriptional activators, which regulate gene expression via complex mechanisms requiring ligand bin ding, transformation, dimerization, and interaction with specific unique ci s DNA hormone response elements (EREs) and co-activators and co-repressors. Studies of ER structure and function have been tremendously facilitated by the development of molecular and biologic probes. Cloning and functional s tudies of the ER alpha and ER beta have delineated some of the structural r equirements involved in receptor function. Immunochemical analyses together with biochemical and molecular approaches have contributed to our understa nding of ER structure and function. Although antibodies to ER have been dev eloped and utilized for the past two decades, there has yet to be a compreh ensive review that discusses the utility and usefulness of these antibodies in receptor detection and analysis. In this review, we summarize a plethor a of information concerning the development and characterization of site-di rected monoclonal and polyclonal antibodies to the ERa and ERP. We provide critical discussion on the characteristics and utility of ER antibodies in analyses, characterization and localization of ER isoforms in various tissu es. We also provide a comparison of the potential utility of the available antibodies in various immunochemical assays. An epitope map detailing the s pecific sites of antibody-receptor interactions is constructed based on the available information. The advent of antibodies with high specificity and titer had facilitated detection of ER isoforms in normal and neoplastic tis sues. The advent of new antibodies remains a powerful tool for assessment o f ER expression and post-translational modification and receptor function i n many experimental systems. (C) 2001 Published by Elsevier Science Inc.