THE HOMEOBOX GENE GOOSECOID CONTROLS CELL-MIGRATION IN XENOPUS EMBRYOS

goosecoid (gsc), a homeobox gene expressed specifically in the dorsal blastopore lip of the Xenopus gastrula, is considered to play an important role in Spemann's organizer phenomenon. Lineage tracing and time-lapse microscopy were used to follow the fate of embryonic cells microinjected with gsc mRNA. Microinjected gsc has non-cell autonomous effects, recruiting neighboring uninjected cells into a twinned dorsal axis. Ectopic expression of gsc mRNA in ventral blastomeres as well as overexpression of gsc in dorsal blastomeres leads to cell movement toward the anterior of the embryo. The results suggest a function for gsc in the control of gastrulation movements in groups of cells, but not in dissociated cells, and demonstrate that a vertebrate homeobox gene can regulate region-specific cell migration.