Identification of the genes exhibiting differential expression along the dorsoventral axis in the tracheoesophageal anlagen.

During development, morphogenetic movement occur that separate the single tube of tracheoesophageal anlagen to the esophagus on the dorsal side and trachea and lung on the ventral side. In this process, signaling factors from the mesoderm induce the function and structure that is specific for esophagus or respiratory system in the lining endoderm. In order to elucidate the mechanism of demarcating these two regions and identify factors that involved in the dorsal and ventral specific inductions, we attempted to identify genes that show different expression in the dorsal and ventral regions using a microarray. The tracheoesophageal anlagen is in a single tube structure and just begin to exhibit the lung bud formation as a swelling at the ventral region around E9.75. We isolated the tracheoesophageal anlagen by dissecting the tube from the posterior end of the pharynx to the posterior end of lung bud swelling and further divided this piece into the dorsal and ventral halves.