Summary of regulatory regions required for Ntng1 and Ntng2 expression. Genomic organization and genomic segments I–VI along with Ntng2 (A) and Ntng1 (B) gene organization are shown. Brain regions positively regulated by the genomic segments are indicated within the designated colored boxes at the bottom. The locations of Ntng1 and Ntng2 enhancers identified are indicated by pink triangles. The combinations of cis-elements that locate distantly and widely from the TSS determine differential expression patterns of the vertebrate-specific paralogs, Ntng1 and Ntng2.