PROBING THE BINDING OF ESTROGEN AND GLUCOCORTICOID RECEPTORS ON CLASSICAL AND NON-CLASSICAL RESPONSE ELEMENTS AND INFLUENCE OF HMGB-1
Abstract (Summary)Estrogen receptor (ER) is a ligand-inducible enhancer protein that is a member of nuclear hormone receptor super family. Estrogen receptors share a highly conserved structure with other members of the steroid receptor super family and a common mechanism, regulating gene transcription. Estrogen receptors reside in the nucleus and in the absence of hormone signal bind to other proteins. However, in the presence of hormone, the receptor dissociates from the other proteins and dimerizes. The dimeric form of estrogen receptor is the active form which binds to a specific DNA sequence, known as the estrogen response element (ERE) in the regulatory region of the target gene. The estrogen response element (ERE) consists of asymmetric or pseudo asymmetric, palindromic repeat of two half-site sequences (cHERE) 5’-AGGTCA-3’, separated by 3bps. HMG domain proteins are architectural proteins involved in chromatin function and have been shown to stabilize the ER/ERE binding. One aims of this thesis is to determine how differences in spacer length between the ERE half-site affect on ER binding affinity in the presence and absence of the coactivator protein, HMGB-1. The binding affinity and selectivity of the two forms of the estrogen receptor (á and â) and glucocorticoid receptor (GR) for cHERE, in three different orientations (direct repeats, inverted repeats and everted repeats) were studied by using the gel mobility shift assay (EMSA). ERs, in contrast to GR, showed a strong cooperativity when interacting with direct repeats, inverted repeats as well as everted repeats.
School Location:USA - Ohio
Source Type:Master's Thesis
Date of Publication:01/01/2007