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Variability and partial synchrony of the cell cycle in the germinal zone of the early embryonic cerebral cortex
Author(s) -
Reznikov Kyrill,
Van Der Kooy Derek
Publication year - 1995
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903600313
Subject(s) - biology , neocortex , neuroepithelial cell , cell cycle , population , mitosis , cerebral cortex , subventricular zone , embryonic stem cell , cortex (anatomy) , microbiology and biotechnology , cell , neuroscience , anatomy , stem cell , neural stem cell , genetics , demography , sociology , gene
Cell cycle parameters were estimated using the cumulative 3 H‐thymidine S‐phase labeling and percentage of labeled mitoses methods in the embryonic day 14 and 15 germinal zone of the rat cerebral cortex. The shortest cell cycle time was seen in the dorsal neocortex and the longest in the lateral neocortex and fimbria (the latter also had a low growth fraction). No differences were observed in cell cycle times between the cells in the ventricular and subventricular zone in the same neocortical region. The results suggest gradients of lengthening cell cycle times extending ventrolaterally and ventromedially from the dorsomedial neocortex. Although a majority of proliferating cells in individual cortical regions seem to belong to one population in terms of cell kinetics, several pieces of evidence suggest some heterogeneity: the asymmetric shapes of the percentages of labeled mitoses curves, the small population of cells that become pyknotic. Groups of DNA‐synthesizing nuclei that were ectopically located in the inner half of the ventricular zone also indicate the existence of different subpopulations of neuroepithelial cells. In addition, after a pulse injection of 3 H‐thymidine the germinal zone is characterized by alternating clusters of heavily and lightly labeled cell nuclei that may reflect the simultaneous passage of a clusters of clel through the same portion of S‐phase. We suggest that partial cell cycle synchrony within groups of ventricular cells may explain the presence of these iterative cell kinetic patterns in the developing cortex. © 1995 Wiley‐Liss, Inc.