The ActR-I activin receptor protein is expressed in notochord, lens placode and pituitary primordium cells in the mouse embryo

Mech Dev. 2000 Mar 1;91(1-2):439-44. doi: 10.1016/s0925-4773(99)00320-2.


ActR-I is a type I serine/threonine kinase receptor which has been shown to bind activin and bone morphogenetic proteins (BMPs). To study the function of ActR-I, we have generated novel monoclonal antibodies that specifically recognize the extracellular domain of mouse ActR-I. We examined the level of ActR-I protein during mouse development by immunohistochemistry. We found that in the embryonic body, ActR-I protein first appears in a restricted part of the primitive streak region and is present throughout the length of notochord. Furthermore, ActR-I protein is expressed in the facial sensory organ primordia, including eye area, otic vesicle and olfactory placode, which all contain invaginating ectoderm. In addition, ActR-I is produced in pituitary primordium (Rathke's pouch), mammary buds and the epithelial layer of branchial arches. Interestingly, in the lens placodes and in early Rathke's pouch, ActR-I protein is transiently localized at the apical surface of the epithelial cells, indicating the presence of an apical-basal asymmetry in these cells.

MeSH terms

  • Activin Receptors, Type I
  • Animals
  • Lens, Crystalline / embryology*
  • Lens, Crystalline / metabolism
  • Mice
  • Notochord / embryology
  • Notochord / metabolism
  • Pituitary Gland / cytology
  • Pituitary Gland / embryology*
  • Pituitary Gland / metabolism
  • Protein Serine-Threonine Kinases / biosynthesis*
  • Receptors, Growth Factor / biosynthesis*
  • Tumor Cells, Cultured


  • Receptors, Growth Factor
  • Protein Serine-Threonine Kinases
  • Activin Receptors, Type I