Pax6 Levels in Neural Stem Cell Self-Renewal Figure 7. Increased expression of Pax6 specifically in the developing cortex alters neocortical stem cell self-renewal and cell fate determination. (A) Genes characteristic of the three main cell types in the embryonic cortex (stem/progenitor cells in the ventricular zone; basal progenitor cells and differentiating neurons) are changed in expression in the D6-Pax6 cortex: there is a striking increase in a set of genes specifically expressed in basal progenitor cells (Eomes/Tbr2, Hes6, Tcfap2c), indicating that there is an increased production of this cell type when Pax6 levels are increased. Genes specifically expressed in layer 5 and 6 neurons are upregulated when Pax6 levels are increased, as are genes associated with cortical neurogenesis (Neurog2, Sox4, Sox21). Conflicting changes in the expression of cell cycle regulators are observed, with increases in expression of PLoS Genetics | www.plosgenetics.org 9 June 2009 | Volume 5 | Issue 6 | e1000511