Cooperation between ARID3A and p53 in the transcriptional activation of p21WAF1 in response to DNA damage

► We examined roles of ARID3A in the regulation of p53-target gene expression. ► ARID3A binds to its binding sites in the p21WAF1 promoter in vivo and in vitro. ► ARID3A cooperates with p53 to activate p21WAF1 transcription. ► Inhibition of ARID3A function inhibited p21WAF1 transactivation after DNA damage. ► Modulation of the ARID3A level affects p53 protein stability.