cell migration (Shworak et al., 1994) and Sdc4 in the proper organization of the actin cytoskeleton and cell adhesion (Gopal et al., 2010). Although co-expressed with Dse in the CNC at the onset of cell migration, Itga5, Itgb1 and Sdc4 mRNAs and the integrin β1 protein level are not altered in DS-epi1-deficient embryos. We did not identify CS or CS/DS chains in endogenous integrin α5β1, and overexpressed Flag–Sdc4 contained HS, but not CS chains, which indicates that the expression and GAG status of this integrin and Sdc4 are not affected by DS-epi1 in Xenopus embryos. A previous finding that purified DS binds to fibronectin (Saito and Munakata, 2007) supports a direct interaction between CS/DS PGs and this extracellular matrix component. Other mechanisms might exist to explain the role of IdoA in cell adhesion and migration. For example, CS/DS PGs might stimulate the cell surface localization of adhesion proteins or cooperate with fibronectin to activate integrins; these processes remain to be investigated.
