Clonal organization in the postnatal mouse central nervous system is prefigured in the embryonic neuroepithelium

We have used the LaacZ clonal method of cell labeling of neuronal ancestors and report that the spatial organization of neuronal cells in the post-nat al CNS shares striking similarities to that in the embryonic neuroepitheliu m, from the spinal cord to the diencephalon. The maintenance of the organiz ation occurs despite massive cell divisions and morphogenetic movements. We deduce that the cellular and architectural organization in the mouse CNS r esults from a succession of patterns of oriented cell dispersion, a general arrest of cell dispersion in the neuroepithelium, and then well-documented radial neuronal migration. The arrest of cell dispersion in the neuroepith elium is consistent with the possibility that an important part of the cell ular and architectural organization of the mature CNS requires conservation of spatial relationship between cells and supports the hypothesis of a tra nsition from global and sparse to local and dense cell interactions occurin g early within the neuroepithelium, (C) 2000 Wiley-Liss, Inc.