Molecular analysis of two closely related mouse aldehyde dehydrogenase genes: identification of a role for Aldh1, but not Aldh-pb, in the biosynthesis of retinoic acid

Abstract

Mammalian class I aldehyde dehydrogenase (ALDH1) has been implicated as a retinal dehydrogenase in the biosynthesis of retinoic acid, a modulator of gene expression and cell differentiation. As the first step towards studying the regulation of ALDH1 and its physiological role in the biosynthesis of retinoic acid, mouse ALDH1 cDNA and genomic clones have been characterized. During the cloning process, an additional closely related gene was also isolated and named Aldh-pb, owing to its high amino acid sequence identity (92%) with the rat phenobarbitol-inducible ALDH protein (ALDH-PB). Aldh1 spans about 45 kb in length, whereas Aldh-pb spans about 35 kb. Both genes are composed of 13 exons, and the positions of all the exon/intron boundaries are conserved with those of human ALDH1. The promoter regions of Aldh1 and Aldh-pb demonstrate high sequence similarity with those of human ALDH1 and rat ALDH-PB. Expression of Aldh1 and Aldh-pb is tissue-specific, with mRNAs for both genes being found in the liver, lung and testis, but not in the heart, spleen or muscle. Expression of Aldh-pb, but not Aldh1, was also detected at high levels in the kidney. Aldh1 and Aldh-pb encode proteins of 501 amino acids with 90% positional identity. To examine the relative roles of these two enzymes in retinoic acid synthesis in vivo, Xenopus embryos were injected with mRNAs encoding these enzymes to assay the effect on conversion of endogenous retinal into retinoic acid. Injection of ALDH1, but not ALDH-PB, mRNA stimulated retinoic acid synthesis in Xenopus embryos at the blastula stage. Thus our results indicate that Aldh1 can function in retinoic acid synthesis under physiological conditions, but that the closely related Aldh-pb does not share this property.

Distinct functions forAldh1 andRaldh2 in the control of ligand production for embryonic retinoid signaling pathways

“…Our distribution of ALDH1 protein agrees with the expression pattern of Aldh1 mRNA, which has previously been observed in mouse liver, intestine, lung, and testis, but not in kidney, brain or heart [López-Fernández and Del Mazo, 1997;Hsu et al, 1999]. The specificity of the ALDH1 antibody is also shown by the presence of a strong signal in the lung, liver, and testis, but a complete absence of a signal in the kidney (Fig.…”

“…A full-length cDNA for mouse Aldh1 (originally known as Ahd2) has been previously described [Hsu et al, 1999]. A full-length cDNA for human ALDH3 has also been described .…”

“…Mouse ALDH1 and RALDH2 proteins were expressed in the E. coli strain BL-21 as Nterminal fusions to Schistosoma glutathione-S-transferase (GST) using pGEX expression vectors (Pharmacia Biotech, Uppsala, Sweden). A 1.6 kb full-length cDNA for mouse Aldh1 [Hsu et al, 1999] was cloned downstream of GST in the EcoRI site of pGEX-4T-2. Likewise, a 1.6 kb full length cDNA for mouse Raldh2 (described above) was cloned into the EcoRI site of pGEX-4T-3.…”

High and complementary expression patterns of alcohol and aldehyde dehydrogenases in the gastrointestinal tract

“…In addition to adult rodents, Adh1 and Adh4 have also been identified in various embryonic tissues [30,31]. Upon entering the body, toxins may also become enzymatically degraded in the liver, which expresses high levels of both Adh [32] and Aldh [33,34].…”

Retinoic acid modulates retinaldehyde dehydrogenase 1 gene expression through the induction of GADD153–C/EBPβ interaction

“…RARα and RXRβ antibodies were purchased from Affinity Bioreagents (Golden, CO). Raldh1 cDNA was provided by Gregg Duester (Burnham Institute, La Jolla, CA) [21] and the type II transglutaminase (TG-II) and RARα cDNA were provided by Ronald M. Evans (Howard Hughes Medical Institute, San Diego, CA) [22]. …”