Fig. 4. The DYT1 gene structure and annotated conserved domain. (A) The genomic region of the DYT1 gene. The dyt1 insertion is flanked by a direct repeat of 6 bp ACTTCT, which correspond to nucleotides 109-104 upstream of the annotated ATG (nucleotides 1-3) codon. The DYT1 gene has three exons represented as white boxes. (B) The annotated amino acid sequence of the DYT1 protein, with 207 amino acid residues. From Phe₂₉ to the Gln₇₈ is the conserved bHLH domain, which corresponds to the black region in the schematic box image and is underlined in the amino acid sequence. (C) An unrooted neighbor-joining tree of Arabidopsis, rice, and Poplar bHLH genes in the same subfamily as DYT1. Gene ID numbers starting with `At' indicate genes from Arabidopsis thaliana; names of genes with functional information are given after the gene ID numbers. Gene ID numbers starting with `Os' indicates genes from rice (Oryza sativa); UDT1 is shown as OsUDT1. `Pt' indicates genes from poplar (Populus trichocarpa), with temporary names given according to gene ID from the Floral Genome Project. Bootstrap values are shown near the relevant nodes.