CONCURRENT CELLULAR OUTPUT FROM 2 PROLIFERATIVE POPULATIONS IN THE EARLY EMBRYONIC MOUSE CORPUS STRIATUM

In mice, the striatal compartment of the forebrain is established by e mbryonic day 11 (E11, EO = day of conception) when a lateral ganglioni c eminence emerges surrounding the lateral and ventral margins of the forebrain ventricles. The inception of the striatal compartment is evi dence of altered cell cycle kinetics, especially a rapid production of postmitotic cells, within a discrete portion of the telencephalic neu roepithelium. As a step toward understanding the mechanisms which cont ribute to the development of a cytokinetically distinct striatal compa rtment, we characterized the rate and pattern of cellular output in th e lateral ganglionic neuroepithelium of mice on Ell. The data show tha t the striatal compartment is distinguished by concurrent and equivale nt levels of cell output from two proliferative populations: a dominan t secondary proliferative population and a smaller, pseudostratified v entricular epithelium. In addition, although the ganglionic neuroepith elium is expanding on Ell, 30-35% of the daughter cells produced leave the cell cycle and become postmitotic. These cytogenetic events, occu rring in the lateral ganglionic progenitor population, may contribute to the development of a distinct striatal compartment within the telen cephalon. (C) 1997 Wiley-Liss, Inc.