INDUCTION OF KIDNEY EPITHELIAL MORPHOGENESIS BY CELLS EXPRESSING WNT-1

During kidney development, unknown signals derived from the ureteric b ud induce metanephric mesenchymal cells to differentiate into nephron epithelia. In addition to the ureteric bud, a number of other tissues can act as heterologous inducers of this process in vitro, including e mbryonic spinal cord. In this report we demonstrate that Wnt-1, a gene that encodes a secreted glycoprotein expressed in embryonic spinal co rd, is capable of conferring nephron-inducing activity to fibroblast c ell lines. When cocultured with cells expressing exogenous Wnt-1, meta nephric mesenchyme differentiated into glomerular and renal tubular ep ithelia. No such effect was observed using control cells. These data i mply that the ability of embryonic spinal cord to act as an inducer of nephrogenesis may result from its production of Wnt-1 protein and sug gest that a member of the Wnt gene family may be a mediator of renal e pithelial morphogenesis in vivo. (C) 1994 Academic Press, Inc.