Supplementary Figure 13: Markers of LGE-cortical boundary in the OSVZ.

The dorsal border of the LGE is neatly marked in the OSVZ by the boundary within which a high level of DLX2 is frequently coexpressed with Ki67 (a), OLIG2 (b), ASCL1 (b), and SOX2 (c) in progenitor cells. In the cortex, DLX2 is expressed at lower levels in post-mitotic inhibitory neurons, in which OLIG2 and Ki67 are completely repressed and SOX2 and ASCL1 are severely downregulated. The OLIG2+ cells in the cortex (b) are DLX2– oligodendrocyte progenitor cells. Note that essentially all COUP-TFII⁺ cells in both the LGE and in the dorsal cortex (a) are DLX2⁺ Ki67^– postmitotic interneurons, the main exception being occasional COUP-TFII⁺ DLX2^– pericytes (see Supplementary Fig. 15e). Note that certain cortical areas outside the dorsal cortex have COUP-TFII⁺ DLX2^– progenitor cells and pyramidal neurons (see Supplementary Fig. 14a).