Involvement of the Guanine Nucleotide Exchange Factor xLARG in the Epiboly of Xenopus laevis Embryo Animal Pole Cells

摘要

The development of multicellular organisms is a complicated coordinated process of the move-ment of groups of embryonic cells, which is controlled by many regulatory systems. At present little is known about the regulation of the earliest manifestations of movement in embryogenesis: epiboly and radial interca-lation. The coordinators of these processes may be small GTPases of the Rho family and their activators, gua-nine nucleotide exchange factors. It has been shown in this work that overexpression of a guanine nucleotide exchange factor xLARG in Xenopus laevis embryos leads to an increase in the amount of the active form of xLARG. In addition, an increase in the expression of xLARG disturbs the process of radial intercalation. The data obtained suggest that xLARG is involved in maintaining the xLARG activation level necessary for the occurrence of epiboly.