Chromatin Immunoprecipation Sequencing in 3T3-L1 preadipocytes using Par-4 antibody

Prostate apoptosis response-4 (Par-4) is a tumor suppressor protein that is extensively investigated in cancer. The objective of this study is to determine the physiological function of Par-4 in normal cells. Our findings indicated that genetic loss of Par-4 in mice primarily results in adipocyte hypertrophy and obesity, and secondary leads to hepatic steatosis and insulin resistance. Moreover, we noted that Par-4 is downregulated in human subjects who are likely to become obese in the future, thereby serving as a predictor of obesity. Importantly, ChIP-Seq indicated that MDM2 is a target of Par-4 protein, which is known to function as a transcriptional coregulator. We show that Par-4 loss upregulates MDM2 target protein p53, and that p53 further induces complement factor C3 and its proteolytic fragment acylation stimulating protein (ASP), an adipokine that is known to be causally associated with obesity. These studies led to the identification of the Par-4-MDM2-p53-C3/ASP axis in regulation of obesity by Par-4. Overall design: We report potential gene targets of Par-4 upon sequencing of ChIP in 3T3-L1 using Par-4 antibody. Sequencing of pulled-down Par-4 antibody-bound chromatin.