Fig. 9

Conditional knock out of Tcf3/12 using Olig1^cre/+results in similar oligodendrocyte defects, without the MGE phenotype observed in Tcf3/12 dcKOs generated with  Olig2^Cre/+. Fate map of Olig2^Cre/+using Rosa^tom/+as a reporter of Cre activation shows recombination throughout the MGE and LGE and cells migrating to the cortex (A). Fate map of Olig1^Cre/+using Rosa^tom/+ shows later recombination in the ventral progenitors and is enriched in OPCs (B). Olig1^Cre/+ driven conditional knockout Tcf3/12 preserves MGE size in the dcKOs, as marked by Nkx2.1 expression (C-E). Similar to Tcf3/12 dcKOs generated with Olig2^Cre/+, Tcf3/12 dcKOs generated with Olig1^Cre/+have a reduction of Olig2 expression in the parenchyma compared to controls at E15.5 (F-H). Tcf3/12 dcKOs generated with Olig1^Cre/+also have a dramatic reduction in Pdgfrα+ and Sox10+ OPCs compared to controls at E15.5 (I-K and L-N, respectively) and reduced numbers of Plp+ cells compared to controls at P21, (O-Q).Scale bars M= 500 μm (for A-M) and P= 1 mm (for O-P)