Xenopus Brachyury

Abstract

Study of Xenopus Brachyury, Xbra, has concentrated on its activation by mesoderm induction and on the effects of over-expression of the gene. Activation of Xbra is an immediate-early response to the mesoderm-inducing factors FGF and activin. The effects of FGF can be mimicked by constitutively active components of the MAP kinase cascade. Over-expression of Xbra in presumptive ectodermal tissue causes ectopic mesoderm formation, with different types of mesoderm being formed in response to different concentrations of Xbra. Future work will study the Brachyury promoter and will attempt to identify targets of this presumptive transcription factor.