Parsons, Amanda (2008) Identification and characterization of a novel interaction between peroxisome-proliferator activated receptor gamma (PPARγ) and mesoderm induction-early response: implications for adipogenesis. Masters thesis, Memorial University of Newfoundland.
- Accepted Version
Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
PPARγ is a nuclear hormone receptor and master regulator of lipid metabolism and adipogenesis. PPARγ regulates these processes through the recruitment of a diverse set of transcriptional coregulators in a tissue and time specific manner. This study focused on characterizing the interaction between PPARγ and mesoderm induction early response 1 (MIER1), a transcription factor that has been shown to interact with other nuclear hormone receptors and regulate target gene expression. Glutathione S transferase pull-down assays have revealed that PPARγ interacts with both MIER1α and β through the common SANT domain. Coimmunoprecipitations in HEK-293 (human embryonic kidney cells) confirmed that this interaction occurs in vivo. A transcriptional reporter assay using luciferase regulated by the PPAR response element (PPRE) demonstrated that MIER1α and β cause a ligand-independent 2-fold activation of PPAR-driven transcriptional activity and this was similar to the 3-fold activation observed with a known PPARγ coactivator (PGC1-α). Thus, MIER1 interacts with PPAR in a ligand-independent manner through its SANT domain, and activates PPARγ -mediated transcriptional activity. PCR analysis showed that MIER1 mRNA expression is upregulated in 3T3-L1 pre-adipocytes during their differentiation into adipocytes. As well, immunocytochemistry revealed that MIER1α is highly expressed specifically in differentiated 3T3-L1s. Future work will determine the exact role of MIER1 in adipogenesis, using shRNA to knockdown MIER1α in the well-established 3T3-L1 differentiation system.
|Item Type:||Thesis (Masters)|
|Additional Information:||Includes bibliographical references (leaves 107-119)|
|Department(s):||Medicine, Faculty of|
|Library of Congress Subject Heading:||Cell differentiation; Genetic transcription; Hormone receptors|
|Medical Subject Heading:||Nuclear Proteins; PPAR gamma; Transcription Factors|
Actions (login required)