Cloning and characterization of human and mouse DDA3 genes

We have previously reported the identification of the mouse DDA3 as a p53- and p73-inducible gene that encodes a protein capable of suppressing cell growth when ectopically expressed. We now report the cloning of the DDA3 cDNA of human as well as the genomic DDA3 DNA of human and mouse. Human DDA3 contains a 1002-bp open reading frame encoding a protein of 333 amino acids that shares 68.2% identity in amino acid sequence to the mouse protein. Expression of the human DDA3 transcript was detectable in various adult and fetal tissues examined, and was most abundantly expressed in the adult brain and fetal thymus. The DDA3 genes for human (7.7 kb) and mouse (6.7 kb) were sequenced; both contained eight exons, the genomic organization and the exon-intron junction sequences were highly conserved. The human DDA3 is located on chromosome 1p13.1, and the mouse gene is mapped to a syntenic region of chromosome 3. Analysis of a 300-kb genomic regions surrounding the mouse and human DDA3 genes revealed that the composition and orders for flanking genes were identical. Together, these results indicate that the newly cloned human gene is an orthologue of the mouse DDA3.