Microarray expression profiling of p53-dependent transcriptional changes in an immortalized mouse embryo fibroblast cell line

The ability of p53 to transcriptionally regulate genes involved with cell cycle progression and apoptosis is critical to its role as a tumor suppressor. Although numerous p53 regulated genes have been identified over the last several years, ablation of any one of these genes cannot account for the full p53-mediated cellular response. Therefore, we performed microarray analysis using two related p53 temperature sensitive cell lines, Val5 and Vm10, to identify novel p53 regulated genes. The Val5 cells undergo p53-mediated cell cycle arrest and the Vm10 cells undergo p53-mediated apoptosis when p53 is in the wild-type conformation. By using these two cell lines, we can compare which genes are regulated by p53 in two different conditions as well as analyze which genes are common to both cell lines. Using the information obtained in the microarray analysis, we confirmed whether a small sub-set of the genes was regulated by p53 using northern blot analysis. By identifying and confirming the regulation of specific genes by p53, we can further characterize biologically why p53 transcriptionally regulates these genes.