Figure 2

Genomic Organization of rat ENaC α, β, and γ subunits. At the genomic level, ENaC α, β, and γ subunits are encoded by three different genes located on separate chromosomes. The gene encoding the α ENaC subunit [Scnn1a] is located on chromosome 4q42, while the β and γ genes [Scnn1b and g] are located at a close proximity from each other on chromosome 1q36-q41 [RGD: Rat Genome Database]. α ENaC is composed of 12 exons, whereas each of the β and γ ENaC genes are composed of 13 exons. Translation starts in exon 1 for α ENaC and starts in exon 2 for β and γ ENaC. Translation ends in exon 12 for α ENaC and in exon 13 for β and γ ENaC. Therefore the 5'untranslated region [UTR] is included in exon 1 of α ENaC and in exons 1 and 2 of β and γ ENaC genes, while the 3'UTR is included in exon 12 of α ENaC and exon 13 in each of β and γ ENaC. Light shaded boxes represent the translated regions, while the black boxes represent the 3' and 5' UTR.