Asymmetric production of surface-dividing and non-surface-dividing cortical progenitor cells.
Mature neocortical layers all derive from the cortical plate (CP), a transient zone in the dorsal telencephalon into which young neurons are continuously delivered. To understand cytogenetic and histogenetic events that trigger the emergence of the CP, we have used a slice culture technique. Most divisions at the ventricular surface generated paired cycling daughters (P/P divisions) and the majority of the P/P divisions were asymmetric in daughter cell behavior; they frequently sent one daughter cell to a non-surface (NS) position, the subventricular zone (SVZ), within a single cell-cycle length while keeping the other mitotic daughter for division at the surface. The NS-dividing cells were mostly Hu+ and their daughters were also Hu+, suggesting their commitment to the neuronal lineage and supply of early neurons at a position much closer to their destiny than from the ventricular surface. The release of a cycling daughter cell to SVZ was achieved by collapse of the ventricular process of the cell, followed by its NS division. Neurogenin2 (Ngn2) was immunohistochemically detected in a certain cycling population during G1 phase and was further restricted during G2-M phases to the SVZ-directed population. Its retroviral introduction converted surface divisions to NS divisions. The asymmetric P/P division may therefore contribute to efficient neuron/progenitor segregation required for CP initiation through cell cycle-dependent and lineage-restricted expression of Ngn2.
Miyata
Takaki
T
Laboratory for Cell Culture Development, Brain Science Institute, RIKEN, Saitama 351-0198, Japan. tmiyata@med.nagoya-u.ac.jp
Kawaguchi
Ayano
A
Saito
Kanako
K
Kawano
Masako
M
Muto
Tetsuji
T
Ogawa
Masaharu
M
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D001921:Brain / Q000196:embryology*; D002453:Cell Cycle; D002455:Cell Division; D019070:Cell Lineage; D002465:Cell Movement; D002540:Cerebral Cortex / Q000196:embryology*; D003094:Collagen / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D016193:G1 Phase; D016195:G2 Phase; D018507:Gene Expression Regulation, Developmental; D049452:Green Fluorescent Proteins; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000096:biosynthesis; D008164:Luminescent Proteins / Q000378:metabolism; D051379:Mice; D008938:Mitosis; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D009474:Neurons / Q000378:metabolism; D012190:Retroviridae / Q000235:genetics; D013234:Stem Cells / Q000166:cytology*; D013687:Telencephalon / Q000196:embryology; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis
D051792:Basic Helix-Loop-Helix Proteins; D003094:Collagen; D049452:Green Fluorescent Proteins; D019394:Ki-67 Antigen; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; C486336:Neurog1 protein, mouse