# Skinbase

##### Mouse Skin and Hair Database

## Matted (ma) and Flaky Tail (ft) Mutant Mice Chr3

- Scanning electron micrograph of scales on the tail of a young flaky tail mutant mouse at 20X magnification.
- Scanning electron micrograph of normal tail skin for a C57BL/6J control mouse. There are no epidermal scales on the surface compared with the age and gender matched flaky tail mouse above.
- Scanning electron micrograph of a hair fiber from a matted mutant mouse. Note the lack of scales on the surface (no cuticle) and the perpendicular black line, part of the region used for focusing which resulting in damaging the fragile fiber.
- Plucked hair from a matted mutant mouse. The fiber is very fragile and ruptures easily.

The matted mutation arose spontaneously in 1952 in the CBA/Gr strain at the University College of London. Mutant mice were imported to The Jackson Laboratory in 1957 and a congenic C57BL/6J strain created. Flaky tail arose spontaneously in 1958 at The Jackson Laboratory in progeny of crosses between heterogeneous stocks. Both mutations map closely on mouse Chr. 3 within the epidermal differentiation gene cluster. They are maintained as a compound mutant as they are tightly linked and their phenotypes do not appear to overlap. The flaky tail mice develop scaling on their tails and feet as early as 2-4 days of age. By 5-14 days of age the tail develops prominent scaling and circumferential constrictions. Autoamputation at these constriction sites can occur resulting in short tails. Lesions begin to resolve at 3-4 weeks of age and are no longer apparent by 5 weeks of age. Mice usually go through puberty around 6 weeks of age so with the exception of the short tails, it can be almost impossible to differentiate wildtype from mutant mice. To circumvent this problem, the matted mutation is maintained on this stock. Matted mutant mice can be identified between 2-4 weeks of age because their truncal hairs stand up and stick together.
Initially, the flaky tail mutant mouse was considered to be a potential model for Vohlwinkle’s Syndrome in humans that was originally thought to be due to a mutation in the loricrin gene. Although the connection was made, the human cases were subsequently classified as pseudVolwinkle’s syndrome. While flaky tail had features resembling this human disease, no mutations in loricrin were found. Subsequently, and adjacent gene, profilaggrin, was considered since flaky tail mutant mice have a marked reduction in the thickness of the stratum granulosum where this protein is found. Immunofluorescence and protein studies revealed marked downregulation of profilaggrin compared to wildtype controls. While the specific profilaggrin repeat has yet to be defined that is abnormal in this gene, similar molecular and clinical features also involving profilaggrin are found in the ichthiosis vulgaris with an agranular layer in human patients.
The matted mutation is currently being cloned. Morphologic studies have been limited but indicate there are defects in the hair follicle matrix and root sheaths. Hair fibers are extremely fragile and lack cuticles. Studies are in progress to define the specific anatomical abnormalities.

### References

Searle AG; Spearman R, Matted (symbol ma), Mouse News Lett 1954;11():29
Searle AG; Spearman RI, 'Matted', a new hair-mutant in the house-mouse: genetics and morphology., J Embryol Exp Morphol 1957;5(1):93-102
Jarrett A; Spearman RI, The keratin defect and hair-cycle of a new mutant (matted) in the house-mouse., J Embryol Exp Morphol 1957;5(1):103-110
Lane PW; Green MC, ft - flaky tail, Mouse News Lett 1962;27():38
Lane PW, Two new mutations in linkage group XVI of the house mouse. Flaky tail and varitint-waddler-J., J Hered 1972 May-Jun;63(3):135-40
Lane PW, Chromosome 12., Mouse News Lett 1975;53():35
Taylor BA, Linkage of the cadmium resistance locus to loci on mouse chromosome 12., J Hered 1976 Nov-Dec;67(6):389-90
Lane PW; Eicher EM, Gene order in linkage group XVI of the house mouse., J Hered 1979 Jul-Aug;70(4):239-44
Eicher EM; Lane PW, Assignment of LH XVI to chromosome 3 in the mouse., J Hered 1980 Sep-Oct;71(5):315-8
Mobraaten LE; Bunker HP; DeMaeyer-Guignard J; DeMaeyer E; Bailey DW, Location of histocompatibility and interferon loci on chromosome 3 of the mouse., J Hered 1984 May-Jun;75(3):233-4
Rothnagel JA; Longley MA; Bundman DS; Naylor SL; Lalley PA; Jenkins NA; Gilbert DJ; Copeland NG; Roop DR, Characterization of the mouse loricrin gene: linkage with profilaggrin and the flaky tail and soft coat mutant loci on chromosome 3., Genomics 1994 Sep 15;23(2):450-6
Sundberg JP, The Flaky Tail (ft) Mutation, Chromosome 3, In: Handbook of Mouse Mutations with Skin and Hair Abnormalities: Animal Models and Biomedical Tools. Sundberg, JP (ed.), CRC Press, Boca Raton, FL, pp 269-273, 1994.
Sundberg JP, The Matted (ma) Mutation, Chromosome 3, In: Handbook of Mouse Mutations with Skin and Hair Abnormalities: Animal Models and Biomedical Tools. Sundberg, JP (ed.), CRC Press, Boca Raton, FL, pp 345-349, 1994
Steele EC Jr; Lyon MF; Favor J; Guillot PV; Boyd Y; Church RL, A mutation in the connexin 50 (Cx50) gene is a candidate for the No2 mouse cataract., Curr Eye Res 1998 Sep;17(9):883-9
Presland RB; Boggess D; Lewis SP; Hull C; Fleckman P; Sundberg JP, Loss of normal profilaggrin and filaggrin in flaky tail (ft/ft) mice: an animal model for the filaggrin-deficient skin disease ichthyosis vulgaris., J Invest Dermatol 2000 Dec;115(6):1072-81
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