title: Constitutive expression of class 3 aldehyde dehydrogenase in cultured rat corneal epithelium.
abstract: Mammalian Class 3 aldehyde dehydrogenase (ALDH) is normally associated with neoplastic transformation or xenobiotic induction by aromatic hydrocarbons in liver. However, Class 3 ALDH is constitutively expressed at it's highest specific activity in corneal epithelium. Tissue-specific, differential gene expression is often controlled by alternative, independent molecular pathways. We report here the development of an in vitro corneal epithelium culture system that retains constitutive high expression of the ALDH3 gene. This model system was used to establish, by enzymatic assays, Western and Northern analyses, histochemical and immunocytochemical staining, and 5'3' RACE methodologies that constitutive and xenobiotic induction of Class 3 ALDHs occurs from a single gene. Our results also provide a plausible explanation for the very high Class 3 ALDH activity in mammalian cornea, as the primary mechanism of oxidation of lipid peroxidation-derived aldehydes. Further studies with corneal epithelium suggest the presence of additional mechanisms, other than Ah-receptor-mediated, by which the ALDH3 gene can be differentially regulated in a tissue-specific manner.
authors.affiliation: Department of Biochemistry, University of South Dakota School of Medicine, Vermillion, 57069, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Boesch
authors.forename: C
authors.initials: C
authors.lastname: Lee
authors.forename: R G
authors.initials: RG
authors.lastname: Lindahl
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000032:analysis / Q000096:biosynthesis*; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002455:Cell Division; D002478:Cells, Cultured; D003315:Cornea / Q000166:cytology / Q000201:enzymology*; D017931:DNA Primers; D004847:Epithelial Cells; D004848:Epithelium / Q000201:enzymology; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis / Q000096:biosynthesis; D007700:Kinetics; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid; D013347:Subcellular Fractions / Q000201:enzymology; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D017931:DNA Primers; D007633:Keratins; D000444:Aldehyde Dehydrogenase