IdoA-containing PGs is compatible with integrin α5β1 subunits (120-150 kDa) (Alfandari et al., 2003) and Sdc4 (40-250 kDa) (Gopal et al., 2010). However, we could not identify CS, CS/DS and HS chains on endogenous integrin α5 and β1 in Xenopus CNC tissue, as well as explants enriched in epidermis and neural crest (Fig. S8A,B). Moreover, we demonstrated that HS, but not CS and CS/DS, chains in Flag-tagged Sdc4 were produced in the mRNA-injected explants (Fig. S8C). In summary, integrin α5β1 and Sdc4 are expressed in CNC cells and do not appear to be decorated with CS or CS/DS chains in Xenopus embryos. These findings suggest that other not yet identified CS/DS PGs might mediate the DS-epi1-dependent CNC cell adhesion on fibronectin.
