Genomic characterization of the MTUS1 gene. Schematic genomic organization of MTUS1 gene is presented in (A). Exons are indicated as boxes with corresponding sizes (bp) indicated above. Alternatively utilized gene promoters (P1, P1', P2, and P3) are indicated in the appropriated locations. 5'-RACE assays were carried out to characterize the 5' untranslated regions (5'-UTRs) corresponding to the long forms of transcription variants (variant 1, 2 and 3), and short forms of transcript variants (variant 4 and 5). The sequence alignments of the 5'-UTRs with human chromosome 8 reference sequence (NT_030737.9), which locate at exon -1a, -1b, -1c, 5 and 8 of the human MTUS1 gene are presented in (B) to (F), respectively. The corresponding GenBank accession numbers for exon -1a, -1b, -1c, 5, and 8 are FJ458439, FJ458440, FJ458441, FJ472826, and FJ472827, respectively.