CSB331H1 Chapter Notes -National College Of Art And Design, Reassortment, Bone Morphogenetic Protein
Fn-containing ecm appears to provide both a substrate for adhesion as well as cues for the direction of cell migration. In xenopus, fn is similarly secreted by the cells lining the blastocoels roof -> band of fn lining the rood. Convergent extension pushes the migrating cells upward toward the ap. Fn fibrils are necessary for the head mesodermal cells to flatten and to extend broad (lamelliform) processes in the direction of migration. Studies using inhibitors of fn formation have shown that fn fibrils are necessary for the direction of mesoderm migration, the maintenance of intercalation of ac cells, and the initiation of radial intercalation in the marginal zone. Mesodermal cells are thought to adhere to a5b1. Mesodermal migration can also be arrested by the microinjection of ab against either fn or a5 subunit. A5 appears just prior to gastrulation and it persists on the surfaces throughout gastrulation and disappears when gastrulation ends.