Effect of β-catenin knockdown on tubule formation and β-catenin target gene expression. HUVECs expressing vGPCR were transiently transfected with siRNA to β-catenin or with non-silencing siRNA control. (A) 72 hr following β-catenin silencing, knockdown efficiency was determined by qRT-PCR. β-catenin mRNA levels were normalized to 36B4 expression. (B) vGPCR-HUVECs were plated on Matrigel as described in Materials and Methods and allowed to form tubules. (C) The number of branch points was determined 6 hr after plating. The data is presented as an average of two independent experiments performed in duplicate. ***p < 0.001.