Publication Date


Document Type


Committee Members

Steve Berberich (Advisor), Mike Markey (Committee Member), John Paietta (Committee Member)

Degree Name

Master of Science (MS)


The p53 protein is a tumor suppressor protein that is mutated or non-functional in nearly all cancers. The Mdm2 protein has the ability to functionally inactivate p53 and these two proteins have been studied extensively in the context of cellular proliferation. In this study, expression of the murine double minute 2 (mdm2) gene was examined in the mouse NIH3T3L1 cell line. Under the proper conditions, the immortalized NIH3T3L1 cells have the ability to differentiate from fibroblasts to adipocytes (Green et al., 1975). This well characterized cell line provides an excellent model to study mdm2 in differentiation. While evaluating the regulation of the mdm2 gene during adipogenesis, it was discovered that NIH3T3L1 preadipocytes possess a 36-fold elevation of mdm2 mRNA relative to A31 cells, another Balb/c 3T3 fibroblast cell line that lacks the capacity to differentiate (Berberich et al., 1999). Based on Southern blot analysis, this increase in mdm2 mRNA is the result of a 60 fold gene amplification (Berberich et al., 1999). This study evaluated how mdm2, p53 and other associated gene products change as NIH3T3L1 cells differentiate from preadipocytes to adipocytes. Most surprising, the mdm2 mRNA and protein levels remained high throughout differentiation and Mdm2 changes localization and interaction with key proteins. This work further proves adipogenesis can occur in the presence of high levels of Mdm2 expression. Herein, Mdm2 is shown to preferentially interact with the retinoblastoma protein, pRb, in terminal adipocytes versus preadipocytes. The p53 mRNA, protein levels and DNA binding (data not shown) decreased and the results suggest that Mdm2 could have a more p53 independent role in adipogenesis. Finally, this work leads to future experiments of determining the importance of high level Mdm2 expression in terminal adipogenesis.

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Department or Program

Department of Biochemistry and Molecular Biology

Year Degree Awarded