Application of efficient and specific gene transfer systems and organ culture techniques for the elucidation of mechanisms of epithelial-mesenchymal interaction in the developing gut

Epithelial-mesenchymal interactions are very important in the development o f the vertebrate gut. In the avian embryonic stomach (proventriculus), expr ession of embryonic chick pepsinogen (ECPg) gene, which is specific to deve loping glandular cells in stomach epithelium, is regulated by mesenchymal i nfluence. Molecular mechanisms of tissue-specific transcriptional regulatio n of the ECPg gene and the molecular nature of the mesenchymal signals were analyzed using a combination of the classic organ culture system and gene transfer strategies. In the present review, three methods for the introduct ion of DNA into tissues are described: lipofection, electroporation and ret roviral infection, and characteristics of each system are discussed.