METANEPHRIC MESENCHYME CONTAINS MULTIPOTENT STEM-CELLS WHOSE FATE IS RESTRICTED AFTER INDUCTION

At least fourteen epithelial cell types of the mammalian nephron devel op from the metanephric mesenchyme. To distinguish whether this single embryological primordium contains a heterogenous population of commit ted renal cell lines or a multipotent stem cell, the lac-Z gene was in troduced into individual renal progenitors by retroviral mediated gene transfer. The differentiated fate of lac-Z-tagged daughters derived f rom single metanephric mesenchymal cells was characterized after cytod ifferentiation. We found that the metanephric mesenchyme contains mult ipotent stem cells that can generate at least three distinct cell type s; glomerular, proximal and distal epithelia. After induction the fate of this multipotent cell becomes restricted to populate a single neph ron segment.