Immunohistochemical study of calpain-mediated alpha-crystallin proteolysis in the UPL rat hereditary cataract.
The UPL (Upjohn Pharmaceutical Limited) rat is a dominant hereditary cataract model that develops early-onset cataracts (E-type) in rats homozygous for the trait, and late-onset cataracts (L-type) in heterozygous rats. Using antibodies specific to the calpain-proteolyzed forms of alpha-crystallin, we determined their immunohistochemical localization of the L- and E-rat lenses. Immunoreactivity indicating the proteolyzed forms was detected and found restricted to degenerated lens fibers of the mature stage of the L-rat cataract. Lenses from E-rats, which have abnormally elongated lens fibers during the fetal period, had proteolyzed alpha-crystallin forms at 1 week of age. The results of this present study indicate that calpain-mediated proteolysis of alpha-crystallin occurred in the UPL rat lenses during cataract formation and that calpain may be an important factor in the development of complete lens opacification.
Tomohiro
M
M
Pharmacia and Upjohn, Tsukuba Research Laboratories, Ibaraki, Japan.
Aida
Y
Y
Inomata
M
M
Ito
Y
Y
Mizuno
A
A
Sakuma
S
S
D000818:Animals; D002154:Calpain / Q000494:pharmacology*; D002386:Cataract / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D003459:Crystallins / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D007124:Immunoenzyme Techniques; D007908:Lens, Crystalline / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D011922:Rats, Mutant Strains
D003459:Crystallins; D002154:Calpain