CELLULAR AND MOLECULAR PARTNERS INVOLVED IN GUT MORPHOGENESIS AND DIFFERENTIATION

The intestinal mucosa represents an interesting model to study the cel lular and molecular basis of epithelial-mesenchymal cross-talk partici pating in the development and maintenance of the digestive function. T his cross-talk involves extracellular matrix molecules, cell-cell and cell-matrix adhesion molecules as well as paracrine factors and their receptors. The cellular and molecular unit is additionally regulated b y hormonal, immune and neural inputs. Such integrated cell interaction s are involved in pattern formation, in proximodistal regionalization, in maintenance of a gradient of epithelial proliferation and differen tiation, and in epithelial cell migration. We focus predominantly on t wo aspects of these integrated interactions in this paper: (i) the rol e of basement membrane molecules, namely laminins, in the developmenta l and spatial epithelial behaviour; and (ii) the importance of the mes enchymal cell compartment in these processes.