Visualization of cell cycling by an improvement in slice culture methods

Slice culture combined with the use of fluorescent dyes and/or the introduction of fluorescent protein genes provides live and three-dimensional information on cytogenetic and histogenetic events at the level of the individual cell. Using slices prepared from midembryonic mouse cerebral wall tissue upon which fine Dil crystals were placed on the pial or ventricular surface, we recently found that dividing progenitor cells do not lose their pia-connected (basal) processes and that the processes are inherited by daughter cells, including neurons (Miyata et al. [2001] Neuron 31:727-741). To understand more fully the biological significance of this inheritance process, the fate of each daughter cell should be monitored over a culture period extended long enough to allow a neuron to migrate up to the cortex or for a progenitor to proceed to the next round of division. Exposure of slices to 40%, instead of 20%, O₂ significantly improved their overall thickening, cell production, and layer formation and also provided better spatial resolution by preventing the loss of transparency that accompanies cell death.