Lens-specific regulation of the thioredoxin-1 gene, but not thioredoxin-2,upon in vivo photochemical oxidative stress in the emery mouse

Thioredoxin (TRX)-1 and TRX-8 redox-regulatory genes were analyzed in the l ens and some other tissues of the Emery mouse, a model for age-related huma n cataract. The cDNA transcripts of mRNAs encoding TRX-1 and TRX-8 genes we re isolated and cloned by RT-PCR from the lens, liver, kidney, and tail, an d the cDNA sequences were similar to the reported sequences of murine TRX-1 and TRX-8 genes. In vivo photochemical oxidative stress to the Emery mice resulted in fivefold upregulation of the lens TRX-1 gene at 3 weeks and dec lined thereafter. Western blot analysis revealed a fourfold increase of TRX -1 protein in the lens at 3 weeks after oxidative stress. The TRX-2 gene in the lens was not changed up to 5 weeks and decreased by 50% thereafter. Ho wever, the expressions of these genes in the liver, kidney, and tail were n ot changed. Fluorescent light or riboflavin alone did not affect the expres sions of TRX-1 and TRX-2 genes in the lens. Thus, we show the expressions o f TRX-1 and TRX-8 genes in the lens, liver, kidney, and tail and lens-speci fic upregulation of the TRX-1 gene and protein expressions, possibly as a p rotective response to the altered redox state of the lens after in vivo oxi dative stress to the Emery mouse. (C) 1999 Academic Press.