CELL-CYCLE KINETICS IN THE EMBRYONIC MOUSE CORPUS STRIATUM

Cells of the corpus striatum arise from the lateral ganglionic eminenc e of the telencephalic neuroepithelium. In mice, the length of the cel l cycle and that of its component phases were estimated, and the inter kinetic nuclear migratory pattern was characterized for lateral gangli onic progenitors on embryonic day 11 and 12 to gain insights into stri atal cytogenetic process. An S-phase labeling paradigm using bromodeox yuridine was employed. To assess regional variation in proliferative p atterns, rostral, middle and caudal levels of the ganglionic neuroepit helium were examined separately. The pattern of interkinetic nuclear m igration and the duration of G1-, G2-, and M-phases at the rostral and middle levels differed from those at the caudal level. The length of the cell cycle and that of the G1-phase increased during the interval embryonic day 11 to 12, especially at the rostral and middle levels. D uring the same interval, a sizable secondary proliferative population emerged at all three levels. Two principal conclusions are drawn: Prog enitors at the different rostrocaudal levels are heterogeneous with re gard to the pattern of cellular proliferation, and ganglionic progenit ors are in advance of the cerebral cortical progenitors based on the r elative size of the secondary proliferative population and the magnitu de of cytokinetic parameters. Thus, proliferative behavior distinguish es progenitor populations at different rostrocaudal levels within the lateral ganglionic neuroepithelium and across the ganglionic and cereb ral cortical domains of the telencephalic neuroepithelium. (C) 1996 Wi ley-Liss, Inc.