Neural stem cells, which differentiate into neurons and glia, are present in the ventricular
zone of the embryonal brain. The precise mechanism by which neural stem cells are
maintained during embryogenesis remains to be determined. Here, we found that transient
misexpression of the basic helix-loop-helix genes Hes1 and Hes5 keeps embryonal
telencephalic cells undifferentiated although they have been shown to induce gliogenesis in
the retina. These telencephalic cells later differentiate into neurons and astroglia when Hes …