In vitro induction of the pronephric duct in Xenopus explants

Dev Growth Differ. 2002 Apr;44(2):161-7. doi: 10.1046/j.1440-169x.2002.00631.x.


The earliest form of embryonic kidney, the pronephros, consists of three components: glomus, tubule and duct. Treatment of the undifferentiated animal pole ectoderm of Xenopus laevis with activin A and retinoic acid (RA) induces formation of the pronephric tubule and glomus. In this study, the rate of induction of the pronephric duct, the third component of the pronephros, was investigated in animal caps treated with activin A and RA. Immunohistochemistry using pronephric duct-specific antibody 4A6 revealed that a high proportion of the treated explants contained 4A6-positive tubular structures. Electron microscopy showed that the tubules in the explants were similar to the pronephric ducts of normal larvae, and they also expressed Gremlin and c-ret, molecular markers for pronephric ducts. These results suggest that the treatment of Xenopus ectoderm with activin A and RA induces a high rate of differentiation of pronephric ducts, in addition to the differentiation of the pronephric tubule and glomus, and that this in vitro system can serve as a simple and effective model for analysis of the mechanism of pronephros differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Activins / pharmacology*
  • Animals
  • Cell Differentiation / drug effects
  • Cell Differentiation / physiology
  • Cytokines
  • Drosophila Proteins*
  • Ectoderm / drug effects*
  • Ectoderm / physiology
  • Embryonic Induction*
  • Genetic Markers / genetics
  • Genetic Markers / physiology
  • Inhibin-beta Subunits / pharmacology*
  • Intercellular Signaling Peptides and Proteins*
  • Kidney / cytology
  • Kidney / embryology*
  • Kidney / ultrastructure
  • Proteins / genetics
  • Proteins / metabolism
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-ret
  • Receptor Protein-Tyrosine Kinases / genetics
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Tretinoin / pharmacology*
  • Xenopus Proteins*
  • Xenopus laevis


  • Cytokines
  • Drosophila Proteins
  • GREM1 protein, Xenopus
  • Genetic Markers
  • Intercellular Signaling Peptides and Proteins
  • Proteins
  • Proto-Oncogene Proteins
  • Xenopus Proteins
  • activin A
  • Activins
  • Tretinoin
  • Inhibin-beta Subunits
  • Proto-Oncogene Proteins c-ret
  • Receptor Protein-Tyrosine Kinases
  • Ret protein, Drosophila