| Primary Identifier | MGI:1855980 | Allele Type | Radiation induced |
| Gene | Tyr | Inheritance Mode | Recessive |
| Strain of Origin | (C3H/HeH x 101/H)F1 | Is Recombinase | false |
| Is Wild Type | false |
| description | This mutation was found in the progeny of a neutron-irradiated male at Harwell. Homozygotes and Tyrc-m/Tyrc-ch heterozygotes have patches of chinchilla-type fur and patches of lighter fur similar to that of Tyrc/Tyrc-ch heterozygotes. The two genotypes are distinguishable by the whiter belly of Tyrc-m homozygous mice (J:13502). Coding regions of the Tyrc-m gene are normal, but upstream sequences are rearranged. Low-level transcription of tyrosinase and reduced sensitivity to DNAase I was found in clones from light pigmenting melanocytes of homozygotes, while in clones from dark pigmenting cells, tyrosinase transcription was higher (though still less than wild-type) and DNAase sensitivity greater. The upstream rearrangement may separate the Tyr structural gene from cis-acting control elements, and the resulting variability of expression cause the light and dark fur patches (J:997). The triple homozygote Tyrc-m/Tyrc-m Mchm1/Mchm1 Mchm2/Mchm2 is essentially a black-eyed white mouse (J:13834). |
| molecularNote | Coding regions of the Tyrc-m gene are normal, but there is a rearrangement of 5'-upstream regulatory sequences including the locus control region of the Tyr gene. Low-level transcription of tyrosinase and reduced sensitivity to DNAase I was found in clones from light pigmenting melanocytes of homozygotes, while in clones from dark pigmenting cells, tyrosinase transcription was higher (though still less than wild-type) and DNAase sensitivity greater. The upstream rearrangement may separate the Tyr structural gene from cis-acting control elements. |
