Overexpression of the Homeobox GeneXnot-2Leads to Notochord Formation inXenopus

AbstractXnot-2is a homeobox gene expressed in Spemann's organizer. Here we present evidence that microinjection of syntheticXnot-2mRNA leads to the formation of notochord. Microinjection into the dorsal side of theXenopusembryo results in greatly expanded notochords. Nearby somitic and prechordal mesoderm becomes recruited into these enlarged notochords, which also affect CNS patterning. Two early genes expressed in the developing notochord,chdandXFKH-1,are activated byXnot-2.We conclude that gain-of-function ofXnot-2promotes notochord formation