Caracul-like 6, 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: Cal6

Mutation (allele) name: caracul-like 6

Gene symbol: Cal6

Strain of origin: B6.129S4 C4tm1Crr/J

Current strain name: B6.129S4 C4tm1Crr/J- Cal6/J

Stock #:005211  (Available as DNA only from the  Jackson  Laboratory DNA Resource)

Phenotypic categories: Hair

Abstract

A spontaneous, dominant, curly coat mutation resembling caracul (Krt2-6gCa) has been discovered and named caracul-like 6 (Cal6). This mutation maps to Chromosome 15 in the same region as Krt2-6gCa. Cal6 may be a remutation to Krt2-6gCa however a direct test for allelism was not performed because caracul is only available as frozen embryos.

Origin and Description

This spontaneous mutation was discovered in a production colony of  B6.129S4 C4tm1Crr/J mice at the Jackson Laboratory in May of 2001 by Serrena Lovley. Mice carrying the Cal6 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. The original caracul mutation has a very similar dominant phenotype showing wavy hair and curved vibrissae and the waves disappear with age, but the hair continues to have a plush look. (MGD 2004)

Genetic Analysis

To determine the mode of inheritance an affected (cal6/+) female was mated to an unrelated normal C57BL/6J male. In 2 litters produced, 7 progeny were affected and 4 were normal, thus proving the mutation  to be dominant.

Cal6 

maps between D15Mit76 and D15Mit16 and is non-recombinant with D15Mit44 in 21 animals typed. The Ensembl placement of these markers and KRT2-6gCa is D15Mit76 at 96.9 Mb, D15Mit44 at 101.0Mb,  Krt2-6gCa at 103.9, and D15Mit16 at 105 Mb. Consequently, it is likely that Cal6 is a remutation to Krt2-6gCa.

Pathology

Our standard pathology screen revealed no lesions in an 8-week  old  Cal6/+ mouse mutant and a +/+ control.

ABR (auditory brainstem response) testing revealed normal hearing in 2 +/Cal6  and 2 +/? controls.

Discussion

Based on it's phenotype and chromosomal location Cal6 may be a remutation to Krt2-6gCa.

Acknowledgements

The authors wish to thank Serrena Lovely  for discovery of the mutant, Heping Yu for ABR testing, 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/)