Towards identifying the molecular mechanisms underlying the Zfhx1b mutant phenotype we used an RNA expression microarray analysis. We compared gene expression from the E12.5 MGE of Nkx2.1-Cre; Zfhx1bF/- mutants to that of Nkx2.1-Cre; Zfhx1bF/+ control littermates. Table S1 (see Table S3 for an extended version) lists the most highly up-regulated and down-regulated genes. Overall, a larger number of genes were found to be significantly up-regulated than down-regulated in Zfhx1b mutants, which may reflect Zfhx1b's function as a recruiter of repressive transcriptional complexes (van Grunsven et al., 2003; Verschueren et al., 1999; Verstappen et al., 2008). We verified the results for many of the genes by performing in situ RNA hybridization on E12.5 control and mutant brains (Figure S6 and data not shown).
