Abstract
Abstract: :
Purpose:Dramatic reductions of the corneal ALDH3A1 enzymatic activities associated with eye pathology were previously reported in C57BL/6J mice subjected to ultraviolet radiation (UVR). The aim of this study was to examine whether UVR diminishes the corneal ALDH3A1 expression through modifications at transcriptional and/or translational level. Methods:Adult C57BL/6J mice were subjected to UVR exposure (302-nm peak wavelength) for various periods of time and corneal ALDH3A1 mRNA and protein levels were monitored by Western and Northern blot analysis, respectively. In addition ALDH3A1 catalytic activities were monitored. Results:Significant reductions of ALDH3A1 protein levels and enzymatic activities were detected 2-4 days post exposure in mice exposed to 0.021 J/cm2 of radiation. No significant changes were observed in the ALDH3A1 mRNA levels in the above animals. However, when mice were exposed to 0.42 J/cm2 radiation a dramatic decrease (about 90%) of the ALDH3A1 mRNA and protein level was detected. Conclusion:It appears that UVR down-regulates the corneal ALDH3A1 expression through transcriptional and/or translational and maybe posttranslational modifications depending on the UVR dose. Reduction in gene transcription requires doses above the threshold, whereas posttranslational protein modifications occur at lower levels.
Keywords: 372 cornea: epithelium • 399 enzymes/enzyme inhibitors • 604 transcription