Lung morphogenesis revisited: Old facts, current ideas

Classical studies using epithelial-mesenchymal recombinants have identified basic rules of how tissue interactions regulate patterning of developing b ranching structures such as the lung. Nevertheless, only recently, molecula r mediators of these interactions have been identified. Formation of bronch i or pre-alveolar structures seems to depend on the activity of distinct ge ne networks along the proximal-distal axis of the respiratory tract. Recent studies reveal that these networks and the mechanisms that they regulate c an be conserved among species and comprise a variety of soluble and transcr iption factors also found in other developing organs. Here, current data an d ideas about how these factors act regulating lung development will be rev iewed. (C) 2000 Wiley-Liss, Inc.