The individual contribution of different progenitor subtypes towards the mature rodent cerebral cortex is not fully understood. Intermediate pro- genitor cells (IPCs) are key to understanding the regulation of neuronal number during cortical development and evolution, yet their exact con- tribution is much debated. Intermediate progenitors in the cortical sub- ventricular zone are defined by expression of T-box brain-2 (Tbr2). In this study we demonstrate by using the Tbr2Cre mouselineand state- of-the-art cell lineage labeling techniques, that IPC derived cells contrib- ute substantial proportions 67.5% of glutamatergic but not GABAergic or astrocytic cells to all cortical layers including the earliest generated subplate zone. We also describe the laminar dispersion of clonally derived cells from IPCs using a recently described clonal analysis tool (CLoNe) and show that pair-generated cells in different layers cluster closer (142.1±76.8 μm) than unrelated cells (294.9±105.4 μm). The clonal dispersion from individual Tbr2 positive intermediate pro- genitors contributes to increasing the cortical surface. Our study also describes extracortical contributions from Tbr2+ progenitors to the lateral olfactory tract and ventromedial hypothalamic nucleus.
Vasistha, N. A., García-Moreno, F., Arora, S., Cheung, A. F. P., Arnold, S. J., Robertson, E. J., & Molnár, Z. (2015). Cortical and clonal contribution of Tbr2 expressing progenitors in the developing mouse brain. Cerebral Cortex, 25(10), 3290–3302. https://doi.org/10.1093/cercor/bhu125