Expression and regulation of alpha 1 beta 1 integrin in Schwann cells

The interaction of cells with the extracellular matrix plays a critical role in morphogenesis and cell differentiation. To define how Schwann cells might interact with the extracellular matrix, we chose to study the expression of the laminin/collagen receptor alpha 1 beta 1 integrin during nerve development in the rat from embryonic day 14 to maturity. We found that this integrin is expressed predominantly on mature non-myelin-forming cells and only at very low levels on myelin-forming cells. Significant levels of this integrin were not detected on Schwann cell precursors or embryonic Schwann cells in vivo. Experiments using transected and crushed sciatic nerve showed that alpha 1 beta 1 integrin expression is regulated at least in part by axonal contact. Furthermore, Schwann cell culture experiments showed that alpha 1 beta 1 integrin levels are strongly upregulated by transforming growth factor-beta s and phorbol esters. (C) 1997 John Wiley & Sons, Inc.