Figure 12.

A cellular and molecular model of the role of the Wls-positive domain in the cerebellar RL development. A, Cellular, The Wls⁺ iRL serves as a reservoir for RL progenitors that will migrate out of the RL through the eRL when these cells turn on Math1 expression. B, Molecular, The molecular interaction between Wls (green), Math1 (blue), and Pax6 (red) in the RL progenitors is proposed based upon experimental results in this paper and other studies. Cells in the iRL express Wls, which activates the expression of Math1 through the action of β-catenin. Expression of Math1 in these cells specifies an RL cell fate and instructs the cells to migrate to the adjacent eRL. In the eRL, these Math1-positive RL progenitors express Pax6. In turn, Pax6 represses the expression of Wls in these RL progenitor cells, providing a negative regulation on Wls and promoting Math1 expression in order for the progenitor cells to differentiate appropriately. CP, choroid plexus; VZ, ventricular zone.