| First Author | Graw J | Year | 1986 |
| Journal | Mouse News Lett | Volume | 76 |
| Pages | 56 | Mgi Jnum | J:30759 |
| Mgi Id | MGI:78298 | Citation | Graw J, et al. (1986) Nop-cataract in mice: altered gene expression of crystallins. Mouse News Lett 76:56 |
| abstractText | Full text of MNL contribution: Nop-CATARACT IN MICE: ALTERED GENE EXPRESSION OF CRYSTALLINS. Graw J., Werner T. Institut fur Saugetiergenetik, Gesellschaft fur Strahlen- und Umweltforschung, Ingolstadter Landstr. 1, D-8042 Neuherberg, FRG. A spontaneous mutation causing a nuclear opacity of the eye lens was detected among (101/ElxC3H/El)F1 hybrid mice. The nuclear opacity, gene symbol Nop, is inherited as an autosomal dominant gene. The mutant can be characterized histologically by an altered differentiation of lens epithelial cell to fiber cells indicated by the presence of cell nuclei throughout the whole lens. Biochemically, the altered differentiation corresponds to a reduced transcription of beta- and gamma-crystallins, which are described as marker proteins for the fiber cells. The reduced concentration of the proteins which is due to a reduced transcription was confirmed by isoelectric focusing of water soluble lens proteins from the living mouse and from cultured lenses. A cell free translation system using lens mRNA yielded comparable results. A more than 50% reduction of beta- and gamma-crystallin mRNA in the cataractous lenses (compared to the wildtype) could be demonstrated by dot blot hybridization with cDNA clones coding for different crystallins (kindly provided by Dr. J. Piatigorsky, NIH, Bethesda, MD, USA). Northern blot hybridization indicates that the size of the mRNA coding for gamma-crystallins is equal both in wildtype and cataractous lenses. Additional biochemical differences between the Nop-cataract and the wlldtype is related to the redox-cycle in the lens. The increased concentration of oxidized glutathione and the enhanced specific activity of the enzyme superoxide dismutase (SOD) in the cataractous lens are indicators for alteration in the redox state, which might be caused by the lowered concentration of the free SH-groups coming from the gamma-crystallins. These observations can be explained by an altered regulation of the expression of beta- and gamma-crystallins. Southern blot hybridizations (Eco RI, Pst I, Nco I) with gamma crystallin specific probes revealed no differences between wildtype and the Nop mutant. More restriction enzymes will be used; Hpa II and Msp I will be included to compare the methylation patterns. Dot blot hybridizations using cDNA for SOD and oncogene probes (fos, myc, myb) are in progress to investigate the cell status of the mutant lens cells. Two genomic libraries from wildtype and homozygous Nop-mutant will provide the molecular basis for the isolation of regulatory sequences of the gamma-crystallins. Footprint assays will be performed to localize trans acting factors influencing the expression of the gamma-crystallins. This work was supported by contract no BI6-156-D of the Commission of the European Communities. |
