Characterization of the mouse aldose reductase gene and promoter in a lens epithelial cell line.

Laboratory of Mechanisms of Ocular Diseases, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.

PURPOSE: To clone and characterize the mouse aldose reductase (AR) gene and evaluate the functional promoter under basal and hypertonic conditions in mouse lens epithelial cells. METHODS: The mouse AR gene structure was determined by DNA sequencing, and its chromosomal localization was determined by fluorescent in situ hybridization. A luciferase reporter gene was utilized to assess promoter activities of mouse, rat, and human AR deletion constructs as well as mouse site-directed mutants containing specific deletions of an aldose reductase enhancer element (AEE) or a tonicity response element (TonE). Electrophoretic mobility shift assays were performed to evaluate binding of trans-acting factors to mouse AEE and TonE. RESULTS: The mouse AR gene (14.2 Kb) is located on chromosome 6. The basal AR promoter activity was greatest for the rat followed by mouse and human. All 3 species demonstrated increased promoter activity under hypertonic conditions. Deletion of TonE decreased mouse AR basal activity 2.5-fold and substantially reduced the osmotic response. Deletion of AEE had only a slight effect on AR promoter activity. Nevertheless, AEE strongly bound multiple trans-acting factors under nonstressed and stressed conditions, while weaker binding was evident for TonE. CONCLUSIONS: Species-specific differences in AR promoter activities suggest the presence of unique regulatory cis-acting elements. The effects of AEE or TonE on AR transcription appear to involve complex transcriptional regulatory mechanisms.

PMID: 9485485 [PubMed - indexed for MEDLINE]