Comparative proteomic analysis identifies age-dependent increases in the abundance of specific proteins after deletion of the small heat shock proteins ?A- and ?B-crystallin.
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ABSTRACT: Mice with deletion of genes for small heat shock proteins ?A- and ?B-crystallin (?A/?B(-/-)) develop cataracts. We used proteomic analysis to identify lens proteins that change in abundance after deletion of these ?-crystallin genes. Wild-type (WT) and ?A/?B(-/-) knockout (DKO) mice were compared using two-dimensional difference gel electrophoresis and mass spectrometric analysis, and protein identifications were validated by Mascot proteomic software. The abundance of histones H2A, H4, and H2B fragment, and a low molecular weight ?1-catenin increased 2-3-fold in postnatal day 2 lenses of DKO lenses compared with WT lenses. Additional major increases were observed in abundance of ?B2-crystallin and vimentin in 30-day-old lenses of DKO animals compared with WT animals. Lenses of DKO mice were comprised of nine protein spots containing ?B2-crystallin at 10-40-fold higher abundance and three protein spots containing vimentin at ?2-fold higher abundance than in WT lenses. Gel permeation chromatography identified a unique 328 kDa protein in DKO lenses, containing ?-crystallin, demonstrating aggregation of ?-crystallin in the absence of ?-crystallins. Together, these changes provide biochemical evidence for possible functions of specific cell adhesion proteins, cytoskeletal proteins, and crystallins in lens opacities caused by the absence of the major chaperones, ?A- and ?B-crystallins.
SUBMITTER: Andley UP
PROVIDER: S-EPMC3690595 | biostudies-literature | 2013 Apr
REPOSITORIES: biostudies-literature
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