A SELF-RENEWING MULTIPOTENTIAL STEM-CELL IN EMBRYONIC RAT CEREBRAL-CORTEX

NEUROECTODERM cells in the cortical ventricular zone generate many div erse cell types, maintain the ventricular zone during embryonic life a nd create another germinal layer, the subventricular zone, which persi sts into adulthood(1,2). In other vertebrate tissues, including skin, intestine, blood and neural crest, stem cells are important in maintai ning a germinal population and generating differentiated progeny(3-6). By following the fates of single ventricular zone cells in culture, w e show here that self-renewing, multipotential stem cells are present in the embryonic rat cerebral cortex. Forty per cent of these stem cel ls produced all three principal cell types of the central nervous syst em: neurons, astrocytes and oligodendrocytes. Stem cells constituted a bout 7% of cortical clones; in contrast, over 80% consisted of small n umbers of neurons or glia. We suggest that multipotential stem cells m ay be the ancestors of other cortical progenitor cells that exhibit mo re limited proliferation and more restricted repertoires of progeny fa tes.