Figure 3.

Expression of HS chains of HSPGs and FGF signalling activation at preimplantation stage. Expression of HS chains examined by the 3G10 monoclonal antibody is observed in the trophectoderm as well as in the inner cell mass at E3.5. FGF signalling activation is monitored by immunohistochemistry with the polyclonal antibody against the dephosphorylated form of Erk (dp-Erk). Expression of dp-Erk is found in the cytoplasm of HS chain-positive cells. The detailed materials and methods are described previously [39].