Cell migration in the Xenopus gastrula.

Xenopus gastrulation movements are in large part based on the rearrangement of cells by differential cell-on-cell migration within multilayered tissues. Different patterns of migration-based cell intercalation drive endoderm and mesoderm internalization and their positioning along their prospective body axes. C-cadherin, fibronectin, integrins, and focal contact components are expressed in all gastrula cells and play putative roles in cell-on-cell migration, but their actual functions in this respect are not yet understood. The gastrula can be subdivided into two motility domains, and in the vegetal, migratory domain, two modes of cell migration are discerned. Vegetal endoderm cells show ingression-type migration, a variant of amoeboid migration characterized by the lack of locomotory protrusions and by macropinocytosis as a mechanism of trailing edge resorption. Mesendoderm and prechordal mesoderm cells use lamellipodia in a mesenchymal mode of migration. Gastrula cell motility can be dissected into traits, such as cell polarity, adhesion, mobility, or protrusive activity, which are controlled separately yet in complex, combinatorial ways. Cells can instantaneously switch between different combinations of traits, showing plasticity as they respond to substratum properties. This article is categorized under: Early Embryonic Development > Gastrulation and Neurulation.