Figure 8. Model for differentiations of mitral cell and interneurons in embryonic olfactory bulb.
Both mitral cell and specific subsets of interneurons are generated from multi-potential Pax6+ progenitor cells in embryonic OB (green) around E11. The differentiation fates of postmitotic cells are regulated by Pax6 expression. Pax6 is down-regulated in majority of E11 generated postmitotic cells to produce mitral cells that are Tbr1+, Tbr2+, and Tbx21+ (thick red arrow). Tbr1 expression precedes Tbr2. If Pax6 is not down-regulated at right time point, the E11-generated postmitotic cells differentiate into interneurons expressing NeuN, GAD67, and/or TH (thin blue arrow).