New horizons at the caudal embryos: coordinated urogenital/reproductive organ formation by growth factor signaling

Curr Opin Genet Dev. 2009 Oct;19(5):491-6. doi: 10.1016/j.gde.2009.08.004. Epub 2009 Sep 16.


The cloaca/urogenital sinus and its adjacent region differentiate into the urogenital/reproductive organs. Caudal regression syndrome (CRS; including mermaid syndrome), a type of severe cloacal malformation displays hindlimb fusion and urogenital organ defects, thus suggesting that such defects are caused by several morphogenetic alterations during early development. The attenuation of bone morphogenetic protein (Bmp) signaling at the posterior primitive streak of embryos leads to the caudal dysmorphogenesis including the cloaca and fusion of both hindlimbs. Genetic tissue lineage studies indicate the presence of coordinated organogenesis. Hedgehog (HH)-responding cells derived from peri-cloacal mesenchyme (PCM) contribute to the urogenital/reproductive organs. These findings indicate the existence of developmental programs for the coordinated organogenesis of urogenital/reproductive tissues based on growth factor function and crosstalk.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Embryo, Mammalian / abnormalities
  • Embryo, Mammalian / embryology*
  • Genitalia / embryology*
  • Hedgehog Proteins / genetics
  • Hedgehog Proteins / physiology
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / physiology*
  • Models, Biological
  • Organogenesis / genetics
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Time Factors
  • Urogenital System / embryology*


  • Hedgehog Proteins
  • Intercellular Signaling Peptides and Proteins