Disruption of lens fiber cell architecture in mice expressing a chimeric AQP0-LTR protein

Aquaporin-0 (AQP0) is the major intrinsic protein of lens fiber cells and t he founder member of the water channel gene family. Here we show that disru ption of the AQP0 gene by an early transposon (ETn) element results in expr ession of a chimeric protein, comprised of similar to 75% AQP0 and similar to 25% ETn long terminal repeat (LTR) sequence, in the cataract Eraser (Cat (Fr)) mouse lens, Immunoblot analysis showed that mutant AQP0-LTR was simil ar in mass to wild-type AQP0, However, immunofluorescence microscopy reveal ed that AQP0-LTR was localized to intracellular membranes rather than to pl asma membranes of lens fiber cells. Heterozygous Cat(Fr) lenses were simila r in size to wild-type but displayed abnormal regions of translucence and l ight scattering, Scanning electron microscopy further revealed that mature fiber cells within the core of the heterozygous Cat(Fr) lens failed to stra tify into uniform, concentric growth shells, suggesting that the AQP0 water channel facilitates the development of the unique cellular architecture of the crystalline lens.