Previous studies suggested that Nkx2-1 promotes interneuron integration into the striatum via repression of Npn2/Sema3-dependent repulsion (Marín et al., 2001; Nóbrega-Pereira et al., 2008). We did not detect a change in Npn2 and Npn1 RNA expression in migrating immature Zfhx1b mutant interneurons at E12.5. On the other hand, van den Berghe et al (in press) present evidence that Zfhx1b regulates interneuron migration through the netrin receptor Unc5b.
