LEFTY1 and teratocarcinoma: We tested RNAi of these genes for effects on endogenous Wnt target gene expression in PA-1 teratocarcinoma cells, which display autocrine Wnt signaling [18], and found that multiple siRNAs for only RNF146 inhibit expression of Wnt-activated genes GAD1 and SAX1, as well as enhance expression of Wnt-repressed genes LEFTY1 and LEFTY2 (Figure 1D).