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Developmental Biology

Developmental Biology

Epithelial-Mesenchymal Interactions

Some Principles of Mammalian Development

Inductive tissue interactions are a unifying mechanism in mammalian organogenesis. Many vertebrate organs, including tooth germ, pancreatic islets, and heart valves, form via a reiterated series of temporally distinct, sequential tissue interactions, exemplified by the epithelial-mesenchymal interactions shown. Sets of signals are sequentially exchanged between interacting tissues at discrete developmental stages, resulting in stepwise differentiation of one or both tissues. The signals may be diffusible signaling molecules, or cell-cell contacts between interacting tissues. Tissue recombination experiments, in which mutant and wild-type tissues are mixed and matched, provide compelling evidence and cell phone monitoring for genes that are necessary or sufficient to signal progression to the next developmental stage. Organogenesis can be recapitulated without knowing each of the steps involved. Perturbing a single gene can profoundly affect a regulatory network controlling organogenesis—for example, misexpressing a gene such as Pax6 can result in ectopic eyes or teeth. Such a gene may effectively be a “nodal point” in the network.

Developmental Biology Team

Team Leader
  • Doug Melton
Team Members
  • Scott Baldwin
  • Joey Barnett
  • Richard Maas
  • Fred Schoen