Tyr^c
Spontaneous Allele Detail

Summary

• Symbol: Tyr^c
• Name: tyrosinase; albino
• MGI ID: MGI:1855976
• Synonyms: c
• Gene: Tyr Location: Chr7:87073979-87142637 bp, - strand Genetic Position: Chr7, 49.01 cM
• Alliance: Tyr^c page

Tyr^c/Tyr^c and Tyr^c/Tyr^c-ch Oca2^p/ Oca2^p

Show the 4 phenotype image(s) involving this allele.

Mutation origin

• Strain of Origin: old mutant of the mouse fancy

Mutation description

• Allele Type: Spontaneous
• Mutation: Single point mutation
• Mutation details: The specific mutation in the albino allele is a G-to-C transversion causing an amino acid change from cysteine to serine at position 103 or 85 (p.C103S for pre-protein, p.C85S for mature protein). This mutation introduces a DdeI enzyme restriction site. (J:10889, J:40223)
• Inheritance: Recessive

Expression

In Mice Carrying this Mutation:	85 assay results
In Structures Affected by this Mutation:	5 anatomical structure(s)

Find Mice (IMSR)

• Mouse strains and cell lines available from the International Mouse Strain Resource (IMSR)
• Carrying this Mutation: Mouse Strains: 79 strains available Cell Lines: 0 lines available
• Carrying any Tyr Mutation: 375 strains or lines available

Notes

Tyr^c, albino. This very old mutant was already known in Greek and Roman times. Hair and eyes are completely devoid of pigment (J:5436, J:5001, J:30725). The albino mutation affects the amount of tyrosinase, and thus of melanin, in pigment cells, but does not interfere with the production of pigment cells themselves (J:12173, J:13092). Melanocytes with melanosomes showing normal fine structure occur in the retina and hair follicles. Pigment granules are smaller and fewer than normal and completely lack melanin (J:5346, J:5001, J:30725). Tyrosinase is almost absent (J:12173). Although Tyr is the structural gene for tyrosinase, some albino mutations may affect tyrosinase enzyme regulation rather than structure (J:6611), suggesting that these mutations affect tyrosinase inhibition (J:5346), presumably via control regions of the gene. All the mutant alleles are recessive to wild-type in phenotype, but heterozygotes with wild-type produce intermediate amounts of tyrosinase (J:12173). Albino-locus mutants with lightly pigmented eyes have a reduced number of fibers of the optic nerve going to the ipsilateral lateral geniculate nucleus of the brain. This is probably a secondary effect of reduced tyrosinase activity or amount of pigment in the pigment epithelium, since genes at other loci that reduce eye pigmentation also cause the same anomaly (J:5436, J:6064). Abnormal retinal pathways disrupted at the optic chiasm that occur in albinism can be corrected with a Tyr normal transgene (J:22320). Lipofuscin is a terminal oxidation product pigment that accumulates with age. In a cross of C57BL/6J and BALB/cJ, which differ in cardiac deposition of the pigment, this trait segregated with albinism, and is controlled by the Tyr locus (J:15460). Tyrc homozygotes do not perform as well as normal in a number of behavioral tests. It is likely that this effect is mediated, at least in part, by defective vision resulting from lack of retinal pigment (J:5470, J:5360, J:5378).

References

• Original: J:34484 Detlefsen JA, A new mutation in the house mouse. Am Naturalist. 1921 Sep-Oct;55:469-73
• All: 44 reference(s)