Gene structure of the human DDX3 and chromosome mapping of its related sequences

The human DDX3 gene (GenBank accession No. U50553) is the human homologue of the mouse Ddx3 gene and is a member of the gene family that contains DEAD motifs. Previously, we mapped the gene to the Xp11.3-11.23 [Park et al. (1998)]. In this report, we describe the structural organization of the human DDX3 gene. It consisted of 17 exons that span approximately 16 kb. An Alu element was present in the intron 13. Its organization was the same as that of the human DBY gene, a closely related sequence present on the Y chromosome. We also identified two processed pseudogenes (DDX3) with a sequence that is highly homologous to those of DDX3 cDNAs, but contain a translation termination codon within its open-reading frame. Pseudogenes are mapped on human chromosomes 4 and X, respectively. In this paper, we discuss the relationships between DDX3 and its related sequences that have been isolated.