Immunochemical comparison of the major intrinsic protein of eye-lens fibre cell membranes in mice with hereditary cataracts

Expression of the major intrinsic protein (MIP) of eye-lens fibre cell membranes was compared in normal (DBA), cataractous (CAT, LOP, NCT) and chimaeric (CBA-LOP) mice at different stages of development using immunofluorescence microscopy and immunoblotting techniques. MIP of apparent molecular mass 26 kDa was detected in extracts of adult DBA, LOP and CBA-LOP lenses, but only low molecular mass (less than 26 kDa) immunoreactive proteins were detected in similar extracts from adult CAT and NCT lenses. The corresponding MIP distribution patterns confirmed the highly organised fibre-cell histology in embryonic DBA and adult CBA-LOP lenses and also highlighted the severe fibre-cell degeneration in the LOP lens. In contrast, however, no immunoreactive MIP was detected in situ in embryonic CAT and NCT lenses. These results suggest that a structural alteration of MIP occurs during embryonic lens development in the cataractous CAT (dominant) and NCT (recessive) mutant mice.