Figure 2

Genomic organization of Tetraodon nigroviridis TnT genes; Genomic organization of Tetraodon fTnTtn (A), AfTnTtn (B) and sTnT2tn (C). Open rectangles represent untranslated regions, while shading represents coding exons. The striped rectangles represent alternatively spliced exons. The arrowheads pointing upwards depict the ATG translational start codon. The three Tetraodon TnT genes have a very similar genomic organizations with exon I containing the start of the 5'UTR, the ATG start site is located in exon II and the last exon codes for the last C-terminal amino acids as well as the entire 3'UTR. In the fTnT gene exons IV and V are alternatively spliced both in Tetraodon and halibut. In the AfTnT gene exon VI is alternatively spliced in Tetraodon but seems to be constitutive in halibut (see Discussion).