These mice carry the spontaneous, semidominant MipCat-Fr mutation and are characterized by pyknosis of the lens fibers followed by cytoplasmic abnormalities eventually leading to anterior polar cataracts.Read More +
Mice carrying the mutation “Shrivelled,” also known as “Cataract-Fraser” or “Cataracta hereditaria subcapsularis,” invariably develop lens opacities which are visible when the animals open their eyes on the fourteenth postnatal day.
Lens development in normal and mutant embryos is the same until day 14 of gestation. At this stage the nuclei of the lens fibers in the controls are large and vesicular with prominent nucleoli. In the mutants the centrally located nuclei are smaller and darker with indistinct nucleoli. The nuclei of normal fibers remain large and open even after birth; those in the mutants continue to undergo pyknosis after passing through the equatorial zone in the regular fashion. The nuclear degeneration is followed, with a delay of about 24-48 hours, by swelling and vacuolization of the fibers concerned. In the adult the lens core forms an amorphous eosinophilic mass or may partly be resorbed. The cortical fibers remain normal. Anterior polar cataracts develop: the epithelial cells proliferate to form multiple layers of atypical cells, surrounded by lens capsule-like material. (from: Zwaan and Williams, 1968, J. Exp. Zool., 169:407-422)
The dominant cataract Frasier mutation arose spontaneously in the A/J strain, but was subsequently bred to Swiss Webster for several years in the laboratory of Dr. Martin Breitman at The University of Toronto. In 1993 heterozygotes that were albino (Tyrc) on a background that might have included one outcross to C57BL/6 (a/a) were rederived into The Jackson Laboratory by crossing with C57BL/6J and the offspring were intercrossed and subsequently maintained by intercrossing homozygotes. Embryos were generated for cryopreservation in 1995 by intercrossing homozygotes, which were black. Because the recessive albino allele was still segregating in these black mice some cryo-recovered pups may be white.
|Allele Name||dominant cataract Fraser|
|Allele Synonym(s)||Cat60; shrivelled; Svl|
|Gene Symbol and Name||Mip, major intrinsic protein of lens fiber|
|Strain of Origin||A/J|
|General Note||In chimeric embryos formed between a strain of mice homozygous for MipCat-Fr and the DBA/2 strain, homozygous for the wild-type Mip allele, the lens is histologically, cellularly, and biochemically normal (J:35863).A study of the lens crystallins shows a decrease in the proportion of a-crystallins and an increase in the proportion of a-crystallins (J:6987). At birth, a-crystallin mRNAs are present in nearly normal amounts and functional capacity but are selectively lost by 40 days of age. The effect is more severe in homozygotes than in heterozygotes. The a-crystallin cellular DNA does not differ from normal (J:7668).|
|Molecular Note||A transposon-induced error in splicing introduces a long terminal repeat sequence replacing the normal carboxy terminus in mutant mice.|
When using the dominant cataract Fraser mouse strain in a publication, please cite the originating article(s) and include JAX stock #002352 in your Materials and Methods section.