TP53 (p53) binds to the p53 response element in the promoter of the MSH2 gene. The p53 response element is flanked by two AP-1 sites. The AP-1 transcription factor complex binds the MSH2 promoter cooperatively with TP53 (Scherer et al. 2000). An additional p53 response element in closer proximity to the MSH2 transcription start site has been reported that does not involve a nearby AP-1 binding site (Warnick et al. 2001).