Heterozygotes and homozygotes have microphthalmia with normal ocular structures except for the lens. Homozygotes are viable and fertile. At embryonic day 12 there is poor elongation of the basal cytoplasm of the central lens fibers and the lens cavity remains open. At embryonic day 13 the elongation of the lens fiber and the convex nuclear arrangement shows poor progression, the central lens fibers are deranged, and the lens fibers are detached from the capsule at the basal surface. At birth the lens is approximately half the normal size and is deformed, with the lens cavity remaining open. In heterozygotes and homozygotes the lens degenerates by 30 days of age.
The eye lens obsolescence mutation arose spontaneously in 1969 in the 4th inbreeding generation of a cross between C57BL/6JNga and a pink-eyed dilution mouse originating from the Japanese fancy mice. An F6 heterozygote was outcrossed to C3Hf/He repeatedly, reaching N18 by 1979. In 1991 congenic homozygous cryopreserved embryos at generation F16 were imported into The Jackson Laboratory from Dr. Loren Skow at Texas A&M and cryorecovered for Dr. Tom Roderick. In 2006 the remaining cryopreserved embryos were recovered to replenish the frozen embryo population and embryos were generated for cryopreservation from their homozygous offspring at generation F17.
|Allele Name||eye lens obsolescence|
|Allele Type||Spontaneous (Dominant negative)|
|Allele Synonym(s)||CrygeCat2-Elo; ELO|
|Gene Symbol and Name||Cryge, crystallin, gamma E|
|Strain of Origin||(C57BL/6JNga x Japanese fancy mouse (Oca2p))F4|
|Molecular Note||A single base (G) deletion at nucleotide position 403 (codon 135) in the fourth ""Greek key"" motif of the Cryge gene product, causes a frameshift mutation that can translate for another 11 amino acids before prematurely terminating (codon 146). The truncated peptide lacking the fourth ""Greek key"" probably leads to misfolding of the crystallin gene product and may act as a dominant negative.|