Mitochondrion-related genes, such as nuclear respiratory factor 1, peroxisome proliferator-activated receptor gamma coactivator 1-alpha, cytochrome C oxidase1, cytochrome C oxidase 2, and superoxide dismutase, are downregulated in the WAT of adipocyte-specific ATF3 transgenic mice compared with WT mice, thus suggesting the ATF3 is involved in adipocyte hypoxia-modulated mitochondrial dysfunction in obesity (36). This evidence concerns the gene ATF3 and obesity due to melanocortin 4 receptor deficiency.