THE COMPLEXITY IN REGULATING THE EXPRESSION OF TENASCINS

The tenascins are a growing family of extracellular matrix proteins of typical multidomain structure. The prototype to be discovered was ten ascin-C. It shows a highly regulated expression pattern during embryon ic development and is often transiently associated with morphogenetic tissue interactions during organogenesis. In the adult organism reexpr ession of tenascin-C occurs in tumors and many other pathological cond itions. Tenascin-C expression can be regulated by many different growt h factors and hormones. Furthermore, mechanical strain exerted by fibr oblasts seems to induce the expression of tenascin-C. This could repre sent a mechanism of translating mechanical forces into protein pattern s, a step of potential relevance in the organization of embryogenesis. Tenascin-C as well as tenascin-R are believed to counteract the cell adhesion and spreading activity of fibronectin, thereby facilitating c ell movement.