Identification of potential co-factors for Ngn2 and Mash1 using bioinformatics approaches in comparative genomics. (a) Putative Ngn2 and Mash1 bindings sites were identified in ECRs in a 500 kb region surrounding 34 Ngn2 and Mash1 target genes (list of target genes analyzed in Additional file 8). Other TFBSs were identified within 30 bp of the putative Ngn2 or Mash1 binding site. (b) TRANSFAC TFBSs that co-occurred with Ngn2 binding sites versus Mash1 binding sites surrounding Ngn2 target genes versus Mash 1 and common target genes, respectively. A total of 58 Ngn2 sites and 56 Mash1 binding sites were analyzed. A * denotes significantly enriched TFBSs in the sequence surrounding Ngn2 sites versus Mash1 sites (Fisher's exact two-sided test with p ≤ 0.05). (c) Comparison of microarray gene expression values of potential Ngn2 and Mash1 co-factors in wild-type dorsal and ventral telencephalon tissues where column three presents results using a 1.5-fold change cut-off value for categorizing gene expression as either preferentially dorsal, ventral, or both (common).