Caracul-like 5, a dominant mutation resembling Krt2-6gCa (caracul) and mapping to the same chromosomal location.

Richard M Samples, Patricia F. Ward-Bailey, Leah Rae Donahue, Roderick T. Bronson and Muriel T. Davisson

Source of Support: This research was supported by grants RR01183 to the Mouse Mutant Resource (M.T. Davisson, PI) and Cancer Core Grant CA34196.

Mutation (allele) symbol: Cal5

Mutation (allele) name: caracul-like 5

Gene symbol: Cal5

Strain of origin: SWR/J

Current strain name: SWR/J- Cal5/J

Stock #:00 5131  (Available as DNA only from the  Jackson  Laboratory DNA Resource)

Phenotype categories: Hair

Abstract

A spontaneous, dominant, curly coat mutation resembling caracul (Krt2-6gCa) has been discovered and named caracul-like 5 (Cal5). This mutation maps to Chromosome 15 in the same region as Krt2-6gCa. Cal5 may be a remutation to Krt2-6gCa however a direct test for allelism was not performed.

Origin and Description

This spontaneous mutation was discovered in a production colony of SWR/J mice at the Jackson Laboratory in August of 2001 by Dawn Martin. Mice carrying the Cal5 mutation are easily recognizable at 3 weeks of age by their very curly coat and kinked vibrissae. With age, the coat of mutant mice straightens some and appears to be rubbed the wrong way, while the vibrissae are kinked to a lesser degree.

Genetic Analysis

To determine the mode of inheritance an affected  female was mated to an unrelated normal C57BL/6J male. In 2 litters produced, 8 progeny were affected and 7 were normal, thus proving the mutation  to be dominant.

Cal5

maps between D15Mit76 and D15Mit263 and is non-recombinant with D15Mit44 in 21 animals typed. The Ensembl placement of these markers and KRT2Ca is D15Mit76 at 96.9 Mb, D15Mit44 at 101.0Mb, D15Mit263 at 101.3 Mb, Krt2Ca at 103.9. Consequently, it is likely that Cal5 is a remutation to Krt2Ca.

Pathology

Our standard pathology screen revealed dyskeratosis of the follicles and hyperplasia of the skin in a 4-week old Cal5/+ mutant mouse.  At 8-weeks of age a different Cal5/+ mouse mutant and a +/+ control had no lesions.

ABR (auditory brainstem response) testing revealed no significant hearing loss in 2 +/Cal5  and 2 +/? controls tested at 4 weeks of age.

Discussion

Based on it's phenotype and chromosomal location Cal5 may be a remutation to Krt2Ca.

Acknowledgements

The authors wish to thank Dawn Martin for discovery of the mutant, and Coleen Marden for excellent technical assistance.

References

Mouse Genome Database (MGD) Mouse Genome Informatics Project, The Jackson Laboratory, Bar Harbor, Maine. World Wide Web

(URL:http://www.informatics.jax.org)

MGSC19.32.2., Mouse Genome Sequencing Consortium

(URL: http://www.ensembl.org/Mus_musculus/)