Characterization of polypeptides from human nuclear cataracts by Western blot analysis.

Water-soluble and water-insoluble polypeptides from nuclei of clear vs. opaque and brunescent human lenses were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrophoretically transferred to nitrocellulose paper. Treatment of the nitrocellulose blots with monospecific antisera to human alpha and beta crystallin and to antisera against the Major Intrinsic Polypeptide (MIP26) of lens membrane demonstrated no difference in binding between microdissected sections of clear vs. opaque (and brunescent) nuclei. In contrast, treatment of nitrocellulose blots with monospecific antisera to human gamma crystallin demonstrated little or no binding to polypeptides from opaque (and brunescent) nuclei as compared with age-matched clear nuclei. These results demonstrate the selective involvement of gamma crystallins in opacification (and brunescence) in the human lens nucleus, and strongly suggest the presence of covalent changes of the gamma crystallin molecule during development of the human nuclear cataract.