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P.V. Rao, R. Maddala, J. Qiu, E. Riggs, A.M. Pendergast; A Role for the c–Abl Tyrosine Kinase Interacting Proteins in Lens Growth and Integrity . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1989.
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© ARVO (1962-2015); The Authors (2016-present)
The Abelson interacting proteins Abi–1 and Abi–2, have been reported to play a critical role in Rac GTPase–, WAVE– and ARP–2/3 complex– regulated actin cytoskeletal dynamics at the cell leading edges and at the cell–cell junctions. In this study we further characterized the ocular phenotype focusing on defective phenotypes in the developing lens in the Abi–2 null/Abi–1 heterozygous and Abi–2 knockout mice.
The distribution of Abi–2 was evaluated by immunofluorescence confocal imaging of the developing mouse lens and primary mouse lens epithelial cultures. Histological changes observed in developing lenses of Abi–2 null mice were compared with those from Abi–1 heterozygous, Abi–2 heterozygous and Abi–2 null /Abi–1 heterozygous lenses.
RT–PCR analysis confirmed the expression of both Abi–1 and Abi–2 in the mouse lenses. Immunofluorescence analysis of Abi–2 in mouse lens epithelial cells revealed localization to the lamellipodia, and cell–cell junctions. In postnatal day one mouse lens cryosections, Abi–2 was distributed along the cell–cell junctions of epithelial and fiber cells, similar to the pattern noted for beta–catenin distribution. Light microscopic histological analysis (H&E staining) of one day–old lenses revealed abnormal lens histology only in the Abi–2 null and in Abi–2 null/Abi–1 (–/+) mice, including failure of the primary lens fibers to reach and form cell attachments with the lens epithelium, an abnormal migration pattern associated with the secondary lens fibers, stunted lens fibers and ruptured posterior lens capsule. These histological changes were found to be much more pronounced in the Abi–2 null/Abi–1 (–/+) mice as compared to the Abi–2 null phenotype. Since the Abi–1 null was lethal at the embryonic stage, it was not included in this study. Among the proteins whose distribution profiles were evaluated in the Abi–2 null/Abi–1 (–/+) mouse lens, including actin, Aquaporin–0, beta–catenin, connexin–50, the organization of actin and the distribution of connexin–50 were noted to be abnormal as compared to the wild type.
Taken together, this data reveal a critical role for the Abi proteins in lens fiber cell migration and assembly of the fiber cell–cell junctions.
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