The androgen receptor (AR) mediates the various actions of androgens and is responsible for the male reproductive system and male phenotype. AR mutations result in variable degrees of androgen insensitivity in XY individuals, ranging from complete to mild androgen insensitivity syndrome (AIS). Most of the AR-mutations are located in the ligand-binding-domain (LBD) and result in a complete or near complete loss of ligand binding. As revealed by several AR-LBD crystal structures, most of these mutations are located far from the bound-ligand, therefore their severe ligand-binding abnormalities must reflect more widespread LBD structural aberrations rather than local distortions at the mutated residues. / To better understand the structural/functional relationship of such mutations, I have characterized the abnormalities associated with alternate substitutions at two identical positions in the AR-LBD (R855H and R855C) and (P892A and P892L) identified in unrelated AIS patients. Results of these analyses have explained the mechanism by which the AR-R855H and AR-R855C resulted in significantly different AIS phenotypes. These studies also revealed that the AR-P892 residue is critical for the dynamic properties of the C-terminal helix (helix 12) of the LBD. Helix 12 dynamic properties are crucial for ligand-binding and for the transactivational properties of the receptor. / To further analyse the properties of the AR-LBD within the context of multiple domains, I have developed a high-yield bacterial-expression method for the production of soluble AR fragment that contains the DNA-binding-domain, the hinge region and the LBD (AR-DBDLBD). This will allow for detailed analyses of the structural and functional properties of these domains and their intra-molecular communications in the presence and absence of DNA and/or ligand. This method is likely to be generally applicable to other nuclear receptors and may resolve the low solubility, instability, and toxicity problems associated with their overexpression. / Furthermore, I have reached the final stages in generating a knockout mouse for a newly identified AR-coregulator, the Androgen Receptor N-terminal- Interacting Protein (ARNIP).
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.111842 |
| Date | January 2006 |
| Creators | Elhaji, Youssef A. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Human Genetics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002563468, proquestno: AAINR27775, Theses scanned by UMI/ProQuest. |
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