Ses (without MLR10 transgene) and lenses of wild-type mice (data not shown). The lens Gclc protein expression was completely abolished in HOMLEGSKO lenses compared to wild type lenses based on westernblot analysis (Fig.1B). This was also confirmed by immunohistochemistry analysis using monoclonal Gclc antibody (data not shown). The deletion of Gclc gene had no impact on glutamatecysteine ligase, modifier subunit (Gclm) protein level (Fig. 1B). Most importantly, the Gclc activity determined by monobromobimane derivatization and HPLC analysis with fluorescence detection clearly demonstrated no detectable activity in HOMLEGSKO lenses (Fig.1C). Interestingly, however, there was only 20 reduction of Gclc activity in HET-LEGSKO lenses compared to wild type lenses. HET-LEGSKO lenses had a ,50 reduction of Gclc mRNA (Fig.1A) and 25 lowerImpact of Suppressed GSH Levels on Lens TransparencyAbout 20 of the homozygous mice developed nuclear opacification starting at 3 months of age based on the sensitivity of Slit-lamp detection, which progressed into severe nuclear cataract at 9 months age. In this report, we define opacity as a white area the size of at least 0.3 micrometer diameter. A typical cataract image (Fig. 4A) shows the same lens at 4 and 9 months of age, whereby the nuclear cataract was found to progress from a small opacity at 4 months to severe nuclear cataract at 9 months. The LEGSKO lenses have relative similar size and weight compared to wild type lenses. The GSH level in the lens nucleus was MNS web barely detectable and GSH level in the lens cortex dropped over 60 compared to age matched wild type lenses (Table 1). The kinetics of the cataract formation was assessed quantitatively using Slit-lamp (Fig. 4B). 50 of HOM-LEGSKO mice had mature cataracts by 4 months compared to age matched wild type mice.Age-Related Nuclear Cataract Animal ModelAge-Related Nuclear Cataract Animal ModelFigure 1. Charaterization of the GSH genotype and phenotype of LEGSKO mouse. 3mos old LEGSKO mouse lens (without cataract) total RNA was extracted and Gclc mRNA was determined by real-time PCR. The data was calculated relative to age matched wild type lenses. Gclc enzyme activity 
was determined by HPLC by monobromobimane fluorescent derivatization. Gclc protein expression was determined by Western-blot. (A). Gclc mRNA 23727046 was reduced 50 in heterozygous mouse lenses and completely abolished in homozygous mouse lenses (n = 6). (B). Gclc protein level was reduced in heterozygous mouse lenses and abolished in homozygous lenses. Mouse liver protein extract was used as PLV-2 positive control. (C). Gclc activity was mildly reduced in heterozygous mouse lenses and quasi no detectable in homozygous mouse lenses (n = 6). (D). Fresh lenses (n = 6) were snap frozen, thaw at room temperature for 1 min and dissected immediately. The protein was precipitated, and the supernatant was subjected to GSH analysis by glutathione reductase (GR) and b-NADPH enzymatic recycling method. (E). the percentage of GSSG vs. GSH was significantly (p,0.0001) elevated in homozygous mouse lenses vs. wild type/heterozygous lenses. (F). Methionine sulfoxide was significantly (p,0.001) elevated in homozygous vs. wild type/heterozygous lenses, and also significantly increased with age (P,0.05). (G). Glutathione reductase (GR) activity, expressed as unit per milligram of protein, was mildly but significantly (P,0.01) reduced in homozygous lenses vs. wild type, and also significantly reduced with age. (H).Ses (without MLR10 transgene) and lenses of wild-type mice (data not shown). The lens Gclc protein expression was completely abolished in HOMLEGSKO lenses compared to wild type lenses based on westernblot analysis (Fig.1B). This was also confirmed by immunohistochemistry analysis using monoclonal Gclc antibody (data not shown). The deletion of Gclc gene had no impact on glutamatecysteine ligase, modifier subunit (Gclm) protein level (Fig. 1B). Most importantly, the Gclc activity determined by monobromobimane derivatization and HPLC analysis with fluorescence detection clearly demonstrated no detectable activity in HOMLEGSKO lenses (Fig.1C). Interestingly, however, there was only 20 reduction of Gclc activity in HET-LEGSKO lenses compared to wild type lenses. HET-LEGSKO lenses had a ,50 reduction of Gclc mRNA (Fig.1A) and 25 lowerImpact of Suppressed GSH Levels on Lens TransparencyAbout 20 of the homozygous mice developed nuclear opacification starting at 3 months of age based on the sensitivity of Slit-lamp detection, which progressed into severe nuclear cataract at 9 months age. In this report, we define opacity as a white area the size of at least 0.3 micrometer diameter. A typical cataract image (Fig. 4A) shows the same lens at 4 and 9 months of age, whereby the nuclear cataract was found to progress from a small opacity at 4 months to severe nuclear cataract at 9 months. The LEGSKO lenses have relative similar size and weight compared to wild type lenses. The GSH level in the lens nucleus was barely detectable and GSH level in the lens cortex dropped over 60 compared to age matched wild type lenses (Table 1). The kinetics of the cataract formation was assessed quantitatively using Slit-lamp (Fig. 4B). 50 of HOM-LEGSKO mice had mature cataracts by 4 months compared to age matched wild type mice.Age-Related Nuclear Cataract Animal ModelAge-Related Nuclear Cataract Animal ModelFigure 1. Charaterization of the GSH genotype and phenotype of LEGSKO mouse. 3mos old LEGSKO mouse lens (without cataract) total RNA was extracted and Gclc mRNA was determined by real-time PCR. The data was calculated relative to age matched wild type lenses. Gclc enzyme activity was determined by HPLC by monobromobimane fluorescent derivatization. Gclc protein expression was determined by Western-blot. (A). Gclc mRNA 23727046 was reduced 50 in heterozygous mouse lenses and completely abolished in homozygous mouse lenses (n = 6). (B). Gclc protein level was reduced in heterozygous mouse lenses and abolished in homozygous lenses. Mouse liver protein extract was used as positive control. (C). Gclc activity was mildly reduced in heterozygous mouse lenses and quasi no detectable in homozygous mouse lenses (n = 6). (D). Fresh lenses (n = 6) were snap frozen, thaw at room temperature for 1 min and dissected immediately. The protein was precipitated, and the supernatant was subjected to GSH analysis by glutathione reductase (GR) and b-NADPH enzymatic recycling method. (E). the percentage 
of GSSG vs. GSH was significantly (p,0.0001) elevated in homozygous mouse lenses vs. wild type/heterozygous lenses. (F). Methionine sulfoxide was significantly (p,0.001) elevated in homozygous vs. wild type/heterozygous lenses, and also significantly increased with age (P,0.05). (G). Glutathione reductase (GR) activity, expressed as unit per milligram of protein, was mildly but significantly (P,0.01) reduced in homozygous lenses vs. wild type, and also significantly reduced with age. (H).
