TP53 (p53) binds the p53 response element in the intron 1 of SCO2 (Synthesis of Cytochrome c Oxidase 2) gene (Matoba et al. 2006). The binding of TP53 on SCO2 gene was verified in a genome wide chromatin immunoprecipitation study (Wei et al. 2006). Tp53 was also found to bind to the promoter region in mouse Sco2 gene to stimulate its expression in response to physical exercise (Qi et al. 2011).
TP53 (p53) directly stimulates transcription of the SCO2 gene. SCO2, synthesis of cytochrome c oxidase 2, is a copper-binding assembly protein for the mitochondrial COX (cytochrome C oxidase) complex which enables aerobic respiration. When SCO2 levels are reduced, as occurs in TP53 deficient cells, the glycolysis becomes the main energy source for the cell. The TP53-mediated regulation of SCO2 and other mitochondrial biogenesis genes provides a possible explanation for the Warburg effect (Warburg 1956) observed in some cancer cells (Matoba et al. 2006).