Dlk1 expression was strongly increased in the VZ and SVZ of the MGE in the Nkx2.1-Cre mutant, and increased weakly only in the SVZ of the MGE in the DlxI12b-Cre mutant. (Figures S6J-S6L’ and S6HH-S6JJ”). Given that Zfhx1b's function was required in the SVZ of the MGE, the increase in Dlk1 expression could play a role in the phenotype. Dlk1 encodes a secreted delta-like ligand (Ferrón et al., 2011; Moon et al., 2002) that could alter Notch signaling. We used electroporation to increase Dlk1 expression in wild type MGE, but failed to identify a change in interneuron migration (data not shown).
