Bred with albino female mice to obtain the germ-line. F1 heterozygous Gclcfl/fl mice were bred with mice carrying a ubiquitously expressing Flp knockin mouse (the Jackson lab, stock No. 009086) on a C57BL/6 background to remove the Neo cassette. The resulting Gclcfl/fl mice were cross-bred to generate the homozygous Gclcfl/fl mouse line. The presence of a ML240 site floxed Gclc allele was identified by PCR using tail DNA with a primer pair (forward primer, 59CATGAGGAA CTGAACTGAAGGATTGA-39; reverse primer, 59-CAAGGAGGCTCACACATCCCAGAAC-39), which generated a 310-bp amplicon.Creation of Lens Conditional Knockout Mouse (Gclcfl/fl/ MRL10+/2)In order to delete Gclc specifically from the lens epithelium and fibers, we crossed the Gclcfl/fl mice with MRL10-Cre mice (FVB background) that express Cre recombinase in lens epithelium and fibers [17]. F1 mice (Gclcfl/wt/MRL10+/2) were backcrossed to Gclcfl/fl mice to generate homozygous lens conditional knockout mice (Gclcfl/fl/MRL10+/2). All the data provide in this paper is based on B6/FVB mixed background. Mice conditionally lacking Gclc in lens (Gclcfl/fl/MRL10+/2), hereafter called LEGSKO, were identified by PCR using both conditional allele (Gclcfl/fl) genotype primer pair and primers pair that amplifies a 190-bp fragment 
of Cre recombinase coding region (forward primer, 59-AATTTGCCTGCATTACCGGTCGATGCAACG-39 and reverse primer 59CCATTTCCGGTTATTCAACTTGCACCATGC-39). Mice were housed under diurnal lighting conditions and allowed free access to food 
and water. All animals were used in accordance with the guidelines of the Association for Research in Vision and Ophthalmology for the Use of Animals in Ophthalmology and Vision Research, and experimental protocols for this study were approved by the Institutional Animal Care and Use Committee (IACUC) of Case Western Reserve University.Materials and Methods Creation of Gclc Floxed MouseGclc conditional knockout (Gclcfl/fl) target ES cells with C57BL/6 genetic background were obtained from the European Conditional Knockout Mouse Program (EUCOMM). The Gclcfl/ fl exon 2 is flanked by two loxP sites, and the Neo cassette is flanked by two FRT sites. Microinjection of ES cells into C57BL/Age-Related Nuclear Cataract Animal ModelFigure 3. Comparison of lens anterior surfaces of 6 mos wild type and Homo-LEGSKO mouse lenses vitally stained for DNA and ROS. Fresh lenses were stained with both Hoechst 33342 and Dihydrorhodamine 123 (DHR). The Lens anterior was scanned using 10X objective, and 65 mm deep into the cortex and 0.8 mm 1326631 layer Z-scan was performed and projection image was obtained with same method for both WT and LEGSKO lenses. (A) and (C). Comparison of DNA staining with Hoechst 33342 (blue) of the anterior surface of Wt and LEGSKO lenses. (B) and (D). Comparison of vital staining for ROS fluorescence with DHR stain (green) of the same surface areas. doi:10.1371/journal.pone.0050832.gQuantitative purchase Tubastatin-A Determination of Reduced Glutathione (GSH) and Oxidized Glutathione (GSSG)Eyes were removed immediately after sacrifice. Lenses were homogenized in 200 ml ice-cold 5 metaphosphoric acid and 0.6 sulfosalicylic acid mixture in 0.1 M potassium phosphate buffer and 5 mM EDTA buffer (pH 7.5). The supernatant was analyzed for GSH and GSSG using glutathione reductase (GR) and b-NADPH enzymatic recycle method followed by colorimetric assay after derivatization with 5,59-dithio-bis(2-nitrobenzoic acid) (DTNB) as described [37]. Commercially available GSH (G6529, Sigma, St. Louis).Bred with albino female mice to obtain the germ-line. F1 heterozygous Gclcfl/fl mice were bred with mice carrying a ubiquitously expressing Flp knockin mouse (the Jackson lab, stock No. 009086) on a C57BL/6 background to remove the Neo cassette. The resulting Gclcfl/fl mice were cross-bred to generate the homozygous Gclcfl/fl mouse line. The presence of a floxed Gclc allele was identified by PCR using tail DNA with a primer pair (forward primer, 59CATGAGGAA CTGAACTGAAGGATTGA-39; reverse primer, 59-CAAGGAGGCTCACACATCCCAGAAC-39), which generated a 310-bp amplicon.Creation of Lens Conditional Knockout Mouse (Gclcfl/fl/ MRL10+/2)In order to delete Gclc specifically from the lens epithelium and fibers, we crossed the Gclcfl/fl mice with MRL10-Cre mice (FVB background) that express Cre recombinase in lens epithelium and fibers [17]. F1 mice (Gclcfl/wt/MRL10+/2) were backcrossed to Gclcfl/fl mice to generate homozygous lens conditional knockout mice (Gclcfl/fl/MRL10+/2). All the data provide in this paper is based on B6/FVB mixed background. Mice conditionally lacking Gclc in lens (Gclcfl/fl/MRL10+/2), hereafter called LEGSKO, were identified by PCR using both conditional allele (Gclcfl/fl) genotype primer pair and primers pair that amplifies a 190-bp fragment of Cre recombinase coding region (forward primer, 59-AATTTGCCTGCATTACCGGTCGATGCAACG-39 and reverse primer 59CCATTTCCGGTTATTCAACTTGCACCATGC-39). Mice were housed under diurnal lighting conditions and allowed free access to food and water. All animals were used in accordance with the guidelines of the Association for Research in Vision and Ophthalmology for the Use of Animals in Ophthalmology and Vision Research, and experimental protocols for this study were approved by the Institutional Animal Care and Use Committee (IACUC) of Case Western Reserve University.Materials and Methods Creation of Gclc Floxed MouseGclc conditional knockout (Gclcfl/fl) target ES cells with C57BL/6 genetic background were obtained from the European Conditional Knockout Mouse Program (EUCOMM). The Gclcfl/ fl exon 2 is flanked by two loxP sites, and the Neo cassette is flanked by two FRT sites. Microinjection of ES cells into C57BL/Age-Related Nuclear Cataract Animal ModelFigure 3. Comparison of lens anterior surfaces of 6 mos wild type and Homo-LEGSKO mouse lenses vitally stained for DNA and ROS. Fresh lenses were stained with both Hoechst 33342 and Dihydrorhodamine 123 (DHR). The Lens anterior was scanned using 10X objective, and 65 mm deep into the cortex and 0.8 mm 1326631 layer Z-scan was performed and projection image was obtained with same method for both WT and LEGSKO lenses. (A) and (C). Comparison of DNA staining with Hoechst 33342 (blue) of the anterior surface of Wt and LEGSKO lenses. (B) and (D). Comparison of vital staining for ROS fluorescence with DHR stain (green) of the same surface areas. doi:10.1371/journal.pone.0050832.gQuantitative Determination of Reduced Glutathione (GSH) and Oxidized Glutathione (GSSG)Eyes were removed immediately after sacrifice. Lenses were homogenized in 200 ml ice-cold 5 metaphosphoric acid and 0.6 sulfosalicylic acid mixture in 0.1 M potassium phosphate buffer and 5 mM EDTA buffer (pH 7.5). The supernatant was analyzed for GSH and GSSG using glutathione reductase (GR) and b-NADPH enzymatic recycle method followed by colorimetric assay after derivatization with 5,59-dithio-bis(2-nitrobenzoic acid) (DTNB) as described [37]. Commercially available GSH (G6529, Sigma, St. Louis).