Fig. 3

Tcf3/12 double conditional knock out using Olig2^cre/+results in fewer oligodendrocyte progenitor cells. Confirmation of Tcf3/12 double conditional KO using Olig2^Cre/+was validated by in situ hybridization with probe against Tcf3 (A-B) and immunostaining with an antibody against Tcf12 (C-D), showing loss of the respective E-protein gene expression in the double conditional knockouts (dcKOs). Olig2 marks neural progenitor cells in the VZ of the MGE and LGE as well as the OL lineage cells away from the VZ. At E15.5, Olig2 is increased in the VZ of the MGE and decreased in the parenchyma of dcKOs compared to controls (red asterisk shows the increased MGE region, E-F, K). Pdgfrα and Sox10 are both markers of OPCs and are largely absent in dcKOs (G-K). At E18.5, remnants of the increased MGE Olig2 expression remains visible, while Olig2 expression outside the VZ is decreased in the dcKOs compared to controls (black arrow for MGE remnant, L-M, R). Pdgfrα and Sox10 remain severely decreased in dcKOs compared to controls at E18.5 (N-R). Quantification of markers at E15.5 in the parenchyma (K) and E18.5 in the striatum (R). Scale bar in J = 500 μm (for A-J) and Q = 1 mm (for L-Q). LGE = lateral ganglionic eminence, MGE = medial ganglionic eminence, CTX = cortex, STM = striatum