Transcriptional regulation of lung development: emergence of specificity

The lung is the product of a set of complex developmental interactions between two distinct tissues, the endodermally derived epithelium and the mesoderm. Each tissue contributes to lung development by fine-tuning the spatial and temporal pattern of gene expression for a distinct array of signaling molecules, transcriptional molecules and molecules related to the extracellular matrix. Morphoregulatory transcriptional factors such as NKX2.1 have the crucial role of connecting the cell–cell crosstalk to the activation or repression of gene expression through which processes such as cellular proliferation, migration, differentiation and apoptosis can be controlled. Although none of the factors participating in lung development are exclusively lung-specific, their unique combinations and interactions constitute the basis for emergence of lung structural and functional specificities. An understanding of the individual molecules and their unique interactions in the context of lung development is necessary for the construction of a morphogenetic map for this vital organ as well as for the development of rational and innovative approaches to congenital and induced lung disease.