Regulated proteolysis of Xom mediates dorsoventral pattern formation during early Xenopus development

Dev Cell. 2002 Oct;3(4):557-68. doi: 10.1016/s1534-5807(02)00270-8.


To identify a regulatory role for proteolysis during early Xenopus development, we developed a biochemical screen for proteins that are degraded in an embryonic stage-specific manner. We found that Xom, a homeobox transcriptional repressor of dorsal-specific genes, was degraded precipitously during early gastrulation. Xom degradation is regulated by phosphorylation at a GSK3-like consensus site and is most likely mediated by the SCF-beta-TRCP complex. Expression of nondegradable Xom represses transcription of dorsal genes much more effectively than wild-type Xom and results in a more strongly ventralized phenotype. We propose that regulated Xom proteolysis plays an essential role in the establishment of the dorsoventral axis, by converting a gradient in BMP abundance into a sharp dorsoventral pattern.

Publication types

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

MeSH terms

  • Animals
  • Body Patterning / physiology*
  • Embryo, Nonmammalian / embryology
  • Glycogen Synthase Kinase 3 / physiology
  • Homeodomain Proteins / physiology*
  • Signal Transduction
  • Transcription Factors / physiology*
  • Xenopus / embryology*
  • Xenopus / physiology
  • Xenopus Proteins*


  • Homeodomain Proteins
  • Transcription Factors
  • Xenopus Proteins
  • ventx2.1 protein, Xenopus
  • Glycogen Synthase Kinase 3