Cloning and characterization of the gene encoding mouse mitochondrial aldehyde dehydrogenase

The mitochondrial (mt) aldehyde dehydrogenase (ALDH2) in liver has been considered to play a major role in the detoxification of alcohol in humans. Using the human ALDH2 cDNA and synthetic oligodeoxyribonucleotides (oligos) as probes, the mouse ALDH2 (mALDH2) gene was isolated and characterized. Nucleotide (nt) sequence analysis revealed an open reading frame (ORF) of 1560 bp encoding a protein of 519 amino acid (aa) residues. The gene is composed of 13 exons and 12 introns and spans approx. 26 kb of the mouse genome. The deduced aa sequence, when compared to the mtALDH2 of human, rat, horse and bovine, revealed 95.8, 99.0, 95.6 and 93.6% aa identity, respectively. Primer extension and rapid amplification of cDNA ends (RACE) experiments showed that the transcription start point (tsp) was 105 bp upstream from the start codon. The promoter region of mALDH2 is devoid of a TATA consensus sequence motif, but putative regulatory elements, including a CAAT box, Sp1-binding site and glucocorticoid-response element (GRE), are present in the promoter region. Northern blot hybridization demonstrated the existence of a high level of mALDH2 mRNA in mouse liver and a low level in mouse kidney.