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Characterization of a mutation in the lens-specific MP70 encoding gene of the mouse leading to a dominant cataract

Item Type:Article
Title:Characterization of a mutation in the lens-specific MP70 encoding gene of the mouse leading to a dominant cataract
Creators Name:Graw, J. and Loster, J. and Soewarto, D. and Fuchs, H. and Meyer, B. and Reis, A. and Wolf, E. and Balling, R. and de Angelis, M.H.
Abstract:During an ethylnitrosourea mutagenesis screen. Aey5, a new mouse mutation exhibiting an autosomal dominant congenital cataract was isolated. The cataractous phenotype is visible at the eye opening and progresses to a nuclear and zonular cataract at 2 months of age with no difference in onset or severity between heterozygous and homozygous mutants. Histological analysis revealed that fiber cell differentiation continues at the lens bow region, but the cell nuclei do not degrade normally and remain in the deeper cortex. Further, the lens nucleus has clefts of various sizes while the remainder of the eye was morphologically normal. The mutation was mapped to chromosome 3 between the markers D3Mit101 and D3Mit77 near the connexin encoding genes Gja5 and Gja8. Sequence analysis revealed no differences in the Gja5 gene, but identified a T→C mutation at position 191 in the Gja8 gene, which was confirmed by an additional Mva12691 restriction site in the genomic DNA of homozygous mutants. This mutation results in Val→Ala substitution at codon 64 of connexin50 (Cx50) also known as lens membrane protein 70 (MP70). Aey5 represents the second dominant mouse cataract mutant affecting Cx50, a membrane protein preferentially expressed in the lens. Since both mutations affect similar regions in the first extracellular domain this region appears to be critically important for its function in lens transparency.
Keywords:Cataract, Connexin50, DNA, Gja8, MP70, Sequence Analysis, Animals, Mice
Source:Experimental Eye Research
Publisher:Academic Press
Page Range:867-876
Date:1 January 2001
Official Publication:https://doi.org/10.1006/exer.2001.1096
PubMed:View item in PubMed

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