Constitutive Expression of Class 3 Aldehyde Dehydrogenase in Cultured Rat Corneal Epithelium (*)
- From the (1)Departments of Biochemistry and Molecular Biology and
- (2)Anatomy and Structural Biology, The University of South Dakota School of Medicine, Vermillion, South Dakota 57069
- § To whom correspondence should be addressed. Tel.: 605-677-5237; Fax: 605-677-5781.
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.
Footnotes
-
↵* The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
-
↵1 The abbreviations used are:
- ALDH
-
aldehyde dehydrogenase
- kb
-
kilobase pair(s)
- PBS
-
phosphate-buffered saline
- 3-MC
-
3-methylcholanthrene
- bp
-
base pair(s)
- UTR
-
untranslated region
- PCR
-
polymerase chain reaction.
-
- Received November 2, 1995.
- Revision received December 18, 1995.
- © 1996 by The American Society for Biochemistry and Molecular Biology, Inc.
