REVIEWS A PEER REVIEWED FORUM Lung Morphogenesis Revisited: Old Facts, Current Ideas

ABSTRACT Classical studies using epitheli-al-mesenchymal recombinants have identified ba-sic rules of how tissue interactions regulate pat-terning of developing branching structures such as the lung. Nevertheless, only recently, molecular mediators of these interactions have been identi-fied. Formation of bronchi or pre-alveolar struc-tures seems to depend on the activity of distinct gene networks along the proximal-distal axis of the respiratory tract. Recent studies reveal that these networks and the mechanisms that they regulate can be conserved among species and comprise a variety of soluble and transcription factors also found in other developing organs. Here, cur-rent data and ideas about how these factors act regulating lung development will be reviewed. © 2000 Wiley-Liss, Inc. Key words: lung development; branching mor-phogenesis; growth factors; pattern formation; organogenesi