Fig. 7.

EGFR⁺ tRGs generate EGFR⁺ PyN-IPCs and EGFR⁺ bMIPCs. A, F Coronal brain sections (60 μm thick) stained for DAPI. B EOMES, EGFR and OLIG2 triple immunostained sections. Note EOMES⁺ cells only in the cortex whereas EGFR⁺ cells in both the cortex and LGE. C Higher magnification images showed EGFR⁺EOMES⁺ PyN-IPCs in the cortical ISVZ and EGFR⁺OLIG2⁺ bMIPCs (arrows) in the cortical IFL. D, E Numbers of EGFR⁺EOMES⁺ cells and EGFR⁺OLIG2⁺ cells in the VZ, ISVZ, IFL and OSVZ of the human cortex at GW18 (D) and GW23 (E). G Some EGFR⁺EOMES⁺ PyN-IPCs in the cortical ISVZ and a large number of EGFR⁺OLIG2⁺ bMIPCs with a large soma in the cortical IFL were shown. Note that EOMES⁺ cells did not express OLIG2. Also note that EOMES was expressed in some EGFR⁺ SNP like cells (had an apical process extended to the ventricular surface, arrowheads in C and G). H Schematic of human cortical tRGs and their direct progeny. Initially, EGFR⁺ASCL1⁺ tRGs produce EGFR⁺ASCL1⁺EOMES⁺ PyN-IPCs, but later they produce bMIPCs that express higher levels of EGFR, ASCL1 and OLIG2. We propose that EGFR⁺ PyN-IPCs differentiate into upper layer PyNs.