We analyzed the effect of deleting Zfhx1b, using Nkx2.1-Cre at multiple developmental stages, including E12.5, E15.5 and P0. To track the fate of Zfhx1b mutant cells, we used the CAG:CAT-EGFP Cre reporter allele (Kawamoto et al., 2000). Mutant brains had the following genotype: Nkx2.1-Cre;Zfhx1bF/-;CAG:CAT-EGFP; whereas controls had the following genotype: Nkx2.1-Cre;Zfhx1bF/+;CAG:CAT-EGFP (on occasion, some were: Nkx2.1-Cre; Zfhx1bF/+). At E12.5, while the control brain showed a robust stream of EGFP+ cells migrating into the cortex, the mutant's EGFP+ MGE derivatives failed to migrate to the cortex, and many were detected in the LGE mantle (Figures 1D-1G’).
