AIDA acts as a ventralizing factor during embryogenesis. This protein inhibits axin-mediated JNK activation by binding axin and disrupting axin homodimerization. This in turn antagonizes a Wnt/beta-catenin-independent dorsalization pathway activated by AXIN/JNK-signaling. Recombinant human AIDA protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.