[Personal contribution to the study of the formation of the tubular epithelial structures].

The function of glandular organs (mammary and salivary glands, exocrine pancreas) depends on their branched tubular epithelial architecture. During pancreas and salivary glands development, we have shown the succession of two opposite epithelial transitions (monolayer --> mass --> tubulo-glandular monolayers). These transitions are controlled by paracrine interactions via mesenchymal cells (SDF-1) and endothelial cells (VEGF), and coordinated by transcriptional networks. The transcription factor HNF-6 is indispensable for tube formation; ZONAB is an actor of the proliferation/differentiation switch, highly expressed in the proliferating epithelial mass. Understanding the mechanisms that control branched glandular differentiation is important for developmental biology and could shed light on polykystic diseases and in situ carcinomas.