BMP-4-responsive regulation of dorsal-ventral patterning by the homeobox protein Mix.1

Nature. 1996 Jul 25;382(6589):357-60. doi: 10.1038/382357a0.


In an expression screen for factors that pattern or induce ventral mesoderm, we isolated a complementary DNA encoding Mix.1, a paired class homeobox gene with no previously known function. Injection of Mix.1 messenger RNA results in extensive blood formation in the whole embryo and transforms dorsal mesoderm to a ventral fate. Mix.1 expression is induced by bone morphogenetic protein-4 (BMP-4), and a dominant inhibitory mutant of Mix.1 can restore a dorsal axis in embryos ventralized by ectopic BMP-4 expression. Mix.1 can form heterodimers with the dorsalizing gene siamois, which encodes a homeodomain protein that is structurally similar to Mix.1. Furthermore, Mix.1 blocks the duplicated axis induced by ectopic siamois expression. Our findings indicate that Mix.1 participates in a BMP-4 signalling pathway to pattern ventral mesoderm, and suggest a model whereby dimerization of homeodomain proteins regulates dorsal-ventral patterning.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bone Morphogenetic Proteins
  • Culture Techniques
  • Embryo, Nonmammalian / physiology*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology*
  • Mesoderm / physiology
  • Morphogenesis
  • Mutagenesis
  • Proteins / physiology*
  • RNA, Messenger / genetics
  • Xenopus
  • Xenopus Proteins*


  • Bone Morphogenetic Proteins
  • Homeodomain Proteins
  • Mix1 protein, Xenopus
  • Proteins
  • RNA, Messenger
  • SIA1 protein, Xenopus
  • Xenopus Proteins