Corneal and stomach expression of aldehyde dehydrogenases: from fish to mammals

We have studied the distribution of the ALDH3Al, ALDH1Al and ALDH2 proteins in the cornea and stomach of several animal species, including mammals (C57BL/6J and SWR/J mice, rat and pig), birds (chicken and turkey), amphibians (frog) and fish (trout and zebrafish). High ALDH3Al protein levels and catalytic activities were detected in C57BL/6J mouse, rat and pig. We found complete absence of the ALDH3Al protein in SWR/J mice, which carry the Aldh3al(c) allele characterized by four amino acid substitutions (G88R, I154N, H305R and I352V) and lack of enzymatic activity. This indicates that the SWR/J mouse strain is a natural gene knockout model for ALDH3Al. Traces of ALDH3Al were detected in rabbit, whereas expression was absent from chicken, turkey, frog, trout, and zebrafish. Interestingly, significant levels of the cytosolic ALDH1Al and mitochondrial ALDH2 proteins were detected by immunoblot analysis in all examined species that are deficient in ALDH3Al expression. In contrast, no ALDH1Al or ALDH2 protein was detected in the species expressing ALDH3A1. It can, therefore, be concluded that corneal expression of ALDH3Al or ALDH1Al/ALDH2 occurs in a taxon-specific manner, supporting the protective role of these ALDHs in cornea against the W-induced oxidative damage. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.