Lhx6 RNA is expressed in tangentially migrating cells that are immature cortical and striatal interneurons, as well as cell types that remain in the subpallium (Flandin et al., 2011; Lavdas et al., 1999; Liodis et al., 2007; Sussel et al., 1999; Zhao et al., 2008). In the Zfhx1b mutant, Lhx6+ cells failed to be detected in the pallium, whereas they continued to be densely located throughout the MGE, and as a scattered population in the LGE and CGE (Figures 1K-1M’). On the other hand, Lhx8 and Gbx2 RNA expression was not appreciably changed in the mutants (Figures S1H-S1J’). Thus, Zfhx1b mutants may have a selective defect in cells fated to become pallial interneurons, but not cholinergic striatal interneurons. To explore this hypothesis we studied the phenotype at later developmental stages.
