Figure 2.

BSN-CM and at least one soluble growth factor are required for branching morphogenesis of the isolated UB. (A) The UB cultured in the absence of BSN-CM and growth factors. (B) The UB cultured with the mixture of growth factors (including EGF, IGF, HGF, FGF-2, and GDNF) but no BSN-CM. (C) The UB cultured in the presence of BSN-CM alone. (D) The UB cultured in the presence of both BSN-CM and the mixture of growth factors. All cultures were carried out for about 1 week and then processed for DB lectin staining. Shown is the three-dimensional reconstruction of confocal images. The isolated UB exhibits branching morphogenesis only in the presence of both BSN-CM and the mixture of growth factors.