CHARACTERIZATION OF SITE-SPECIFIC POLYCLONAL ANTIBODIES TO C-ERBA PEPTIDES RECOGNIZING HUMAN THYROID-HORMONE RECEPTOR-ALPHA-1, RECEPTOR-ALPHA-2, AND RECEPTOR-BETA AND NATIVE 3,5,3'-TRIIODOTHYRONINE RECEPTOR, AND STUDY OF TISSUE DISTRIBUTION OF THE ANTIGEN

The translated products of v-erbA-related cDNAs have been demonstrated to be thyroid hormone receptors, and three different forms of receptor (αl, α2, and β) have been found in human tissues. We synthesized five peptides corresponding to different portions of these three receptors and raised site-specific polyclonal antipeptide sera in rabbits. Each antibody displayed high titer and specificity for its respective antigen when tested in an enzyme-linked immunosorbent assay. Each immunoprecipitated the corresponding in vitro translated products of human c-erbA αl, α2, or β. Two of the antisera were specific for ß, one for a2, and one detected a sequence common to αl and α2. The fifth was directed toward the DNA-binding area of the proteins and interacted with each receptorThe four antibodies against al and β immunoprecipitated the native thyroid hormone receptor from rat liver and caused a partial shift in the elution profile of the native receptor labeled with [126I]T3 on Sephacryl S-300 column chromatography. The antibody against α2 protein did not interact with native thyroid hormone receptor from rat liverUsing the indirect immunofluorescence technique with the five antibodies, we detected immunoreactivity primarily in the nucleus of cells in several tissues. In general, there was coordinate expression of both α and β receptors in each organ examined, in agreement with previous data on tissue distribution of mRNAs for human thyroid hormone receptors. These studies prove the identity of v-erbA-related gene products with native thyroid hormone receptors and the expression of both α and β receptors in nuclei of human and rat tissues. © 1990 by The Endocrine Society.