First published online January 12, 2006
Development 133, 302e (2006)
© The Company of Biologists Limited
Reelin-in neocortical layers
The neocortex – the outer region of the mammalian brain –
contains distinct layers of cells that develop in a specific spatiotemporal
order. Reelin, which is mainly made by Cajal-Retzius (CR) cells in the
developing neocortex, is essential for this process, but it is unclear whether
this secreted glycoprotein provides positional information or is permissive
for cell migration. On p.
537, Yoshida and colleagues provide strong evidence for the latter
role. CR cells arise from the cortical hem of the developing mouse brain.
Unexpectedly, when the researchers genetically ablated the hem, neocortical
layers formed in the normal order in mutant embryos, even though most CR cells
were lost; in reeler mice, which lack functional reelin but have CR
cells, the layers are inverted. The researchers suggest that reelin diffusing
in from elsewhere in the brain can compensate for CR cell loss and that,
therefore, layer order is not driven by positional information from a
localised source of reelin.
Related articles in Development:
- Massive loss of Cajal-Retzius cells does not disrupt neocortical layer order
- Michio Yoshida, Stavroula Assimacopoulos, Kevin R. Jones, and Elizabeth A. Grove
Development 2006 133: 537-545.
[Abstract]
[Full Text]
