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Full-Text Articles in Molecular Biology

Cooperative Tumor Suppression By Arf And P53, Jason Thomas Forys Nov 2013

Cooperative Tumor Suppression By Arf And P53, Jason Thomas Forys

All Theses and Dissertations (ETDs)

Cancer is a complex genetic disease characterized by the inactivation of tumor suppressor genes and enhanced activity of oncogenes leading to deregulated cellular proliferation. Two tumor suppressor genes, p53 and Arf, play important roles in protecting cells against numerous biological stresses. In response to oncogenic signals, increased ARF expression leads to the activation of p53, which in turn leads to the cessation of cell division or induction of an apoptotic response. Interestingly, p53 coordinates repression of Arf transcription, setting up a negative feedback loop with currently unknown physiological significance. Cells that lack p53 express elevated levels of ARF, but it …


Inhibition Of P53 Dna Binding Function By The Mdm2 Acidic Domain, Brittany Lynne Cross Jan 2011

Inhibition Of P53 Dna Binding Function By The Mdm2 Acidic Domain, Brittany Lynne Cross

USF Tampa Graduate Theses and Dissertations

MDM2 regulates p53 predominantly by promoting p53 ubiquitination. However, ubiquitination-independent mechanisms of MDM2 have also been implicated. Here we show that MDM2 inhibits p53 DNA binding activity in vitro and in vivo. MDM2 binding promotes p53 to adopt a mutant-like conformation, losing reactivity to antibody Pab1620, while exposing the Pab240 epitope. The acidic domain of MDM2 is required to induce p53 conformational change and inhibit p53 DNA binding. ARF binding to the MDM2 acidic domain restores p53 wild type conformation and rescues DNA binding activity. Furthermore, histone methyl transferase SUV39H1 binding to the MDM2 acidic domain also restores p53 wild …