Fig. 1.
The proliferating SVZ cells originate from the VZ. (A) Two hours after BrdU injection (i.p. 50 mg/kg), BrdU-labeled cells (green) in the embryonic mouse neocortex locate at both the VZ and the SVZ (E16), which suggest these cells were in the S-phase. The contour of the neocortex is shown by Tuj-1 staining (red). Scale bar: 15 μm. (B) The plasmid expressing EGFP (pCAG-EGFP) was electroporated into the VZ cells at the ventricular surface at E14. Immunostaing for M phase marker phosphor-Histone-H3 (pH3) was performed at E15. pH3+ cells are observed in the SVZ and are colocalized with EGFP (arrows), which suggests these proliferating SVZ cells originate from the VZ. Scale bar: 10 μm. (C) Schematic diagram shows the behavior of INPs in the SV/SVZ. The M phase cells at the ventricular surface generate INPs via asymmetric division. The INP migrates to the SVZ to generate two postmitotic neurons (PNs) via symmetric division. ATP released in the VZ/SVZ activates the P2Y1 receptor expressed in VZ/SVZ cells, including the RGs and INPs. Activation of P2Y1 receptor in INPs will induce Ca2+ transients and modulate their migration from the VZ to the SVZ.