New strain highlight

Newly characterized spontaneous mutants 

The Mouse Mutant Resource (MMR) isolates exceptional mice with rare genetic conditions as they arise in colonies at JAX and identifies altered underlying causative genes. We develop strains from these spontaneous mutants that may serve as animal models for corresponding human genetic illnesses. Recently characterized mutants provide promising disease models for autoimmune and dermatologic conditions, as well as dental and skin diseases. 

The buttery ruffled fur (burf) mutant strain represents the first spontaneously arising mutant allele of the mouse (and corresponding human) gene known as Elovl3/ELOVL3. These genes are known to play a role in the synthesis of long-chain fatty acids. JAX burf mice exhibit abnormal ruffled cream-colored fur and hair with abnormally high levels of eicosenoic-acid (a long chain fatty-acid). The skin of burf mice (and presumably also humans) lacks a normal and vital function as a water barrier. 

The dwss mouse is a model of autoimmune and dermatologic disorders. Shown are two male littermates, 35 days of age. The mouse on the left is mildly affected, exhibiting tufted fur and reddened skin (dwss/dwss). The mouse on the right is unaffected.

The dermatitis with small size (dwss) mutant strain represents the first known mutant form of the mouse gene Gm15448. JAX dwss mice have rough tufted hair and reddened skin with chronic ulceration. Interestingly, the mouse gene has similarity to the human LILRB3 gene, one member of a large family of immune system suppressors. One reasonable hypothesis is that when Gm15448 is defective, as it is in the dwss strain, some facets of the immune system may run rampant and result in the observed skin condition. Further understanding the abnormalities of the dwss strain may provide useful insights for unraveling and treating some human autoimmune and dermatologic conditions. 

The dense incisors (din) mutant strain identifies an important gene function where none may have been previously suspected. The din mutation arose in a JAX mouse on Chromosome 16, in a poorly characterized gene impersonally named 4930453N24Rik. The corresponding human gene on Chromosome 3, C3ORF38, does not yet have any associated disease phenotypes. Although 13 mouse embryonic stem cell lines exist in the scientific community with engineered din mutations, none has yet been developed into mice, presumably because any possibly interesting health condition remained unknown. The din strain has provided some insights. JAX din mice have light underfur, unusual white ears, delayed growth and perhaps most important, non-erupting lower incisors. Thus, the din strain offers the first clues to the functions of the mouse and human genes and provides an immediate candidate for any human dental or pigmentary syndrome associated with the corresponding region of human Chromosome 3.