Steel 22 Jackson KitlSl-22J; a new remutation in the Kitl gene.

Steel 22 Jackson Kitl^Sl-22J; a new remutation in the Kitl gene.

Authors: Richard Samples, Louise Dionne, Patricia Ward-Bailey, Roderick Bronson, and Kenneth R. Johnson

Source of Support:The research was supported by NIH/NCRR grant RR01183 to the Mouse Mutant Resources (M. T. Davisson PI) and Cancer Center Core Grant CA34196

Mutation (allele) symbol: Kitl^Sl-22J

Mutation (allele) name: Steel 22 Jackson

Gene symbol: Kitl

Strain of origin: C57BL/6-Ins2^Akita/J

Current strain name: C57BL/6J-Kitl^Sl-22J/J

Stock #: 006839 (view JAX® Mice Data Sheet for additional information including Price and Supply Information). Note: As of October 21,2008 available as DNA only from the Jackson Laboratory DNA Resource. interested parties may also refer to Stock # 003252, #000160, and # 000693.

Phenotype categories: coat color

Abstract

A spontaneous, dominant coat color mutation that maps to the same region as Kitl on Chromosome 10 has been characterized and named steel 22 Jackson (Kitl^Sl-22J).

Origin and Description

The steel 22 Jackson (Kitl^Sl-22J) mutation was discovered by Kristy Martin in a production colony of C57BL/6-Ins2^Akita/J mice (Stock #003548) at The Jackson Laboratory. Like the previously described Kitl^Sl, mice heterozygous for the new spontaneous, dominant Kitl^Sl-22J mutation are recognized by a slightly diluted coat color that also lightens the ears, tail and feet (See photo). All affected animals have a belly spot of variable size (See photo).

Genetic Analysis

In order to determine the mode of inheritance for this new remutation, a mouse carrying the Kitl^Sl-22Jmutation was mated to an unrelated +/+ C57BL/6J mouse. This mating produced a litter of 6 progeny of which 3 were affected by the mutant phenotype and 3 were unaffected, proving that the mutation is dominant.

Using our standard mapping procedures two females, homozygous for the Kitl^Sl-^22J mutation were mated to a CAST/Ei male mouse. The progeny from this previous cross were then backcrossed to three +/+ C57BL/6-Ins2^Akita/J mice and they produced 58 offspring that were utilized for linkage analysis. The new Kitl^Sl-22J remutation was mapped to Chromosome 10 and is distal to D10Mit96 (NCBIm36 position 98.9 Mb) and proximal to D10Mit70 (NCBIm36 position 103.5 Mb) and non-recombinant with D10Mit178 (NCBIm36 position 99.6 Mb). The previously described Kitl^Sl is at (NCBIm36 position 99.4-99.5 Mb).

Pathology

A routine pathological screen of two mutant and two littermate controls at 8 weeks of age showed no gross abnormalities.

Hearing as assessed by auditory brainstem response (ABR) testing of two heterozygous mutants and 2 controls at 4 weeks of age revealed no hearing loss.

The eyes of one mutant and one control at 33 weeks of age were examined with an opthalamascope and the mutant had areas of pigment loss in peripheral retina. This same mutant and control were ERG tested and both were normal.

Discussion

Based on phenotype and map position, this new remutation was determined to be an allele of the Kitl gene. A direct test for allelism was not performed as both Kitl and the new Kitl^Sl-22J have dominant inheritance.

Acknowledgements

The authors thank Kristy Martin for discovery of the new remutation, Norm Hawes for the eye examination, Heping Yu for the hearing assessments, ad Coleen Marden for histological skills.

The Jackson Laboratory