Pearl 14 Jackson, a remutation of the Ap3b1 gene
Richard M. Samples, Patricia F. Ward-Bailey, Leah Rae Donahue, Roderick T. Bronson, and Muriel T. Davisson
Source of Support: The research was supported by NIH/NCRR grant RR01183 to the Mouse Mutant Resource (M.T. Davisson, PI) and Cancer Center Core Grant CA34196.
Mutation (allele) symbol: Ap3b1pe-14J
Mutation (allele) name: pearl 14 Jackson
Gene symbol: Ap3b1
Strain of origin: B6;129S2-Seletm1Hyn/J
Current strain name: B6;129S2-Seletm1Hyn/J-Ap3b1pe-14J /J
Stock #:005532 (Note: as of July 27,2006 available as DNA only from the DNA Resource at theJacksonLaboratory).
Phenotype categories: Coat colorOrigin and Description
The Ap3b1pe-14J remutation was discovered by Ralph Bernaquer in a production colony of B6,129Sele<tm1Hyn>/J mice in Annex 1 at The Jackson Laboratory on June 6, 2001. Mice homozygous for this spontaneous, recessive remutation are recognizable by a diluted gray coat color similar to, but slightly darker than the original pearl allele (MGD 2005). The slight darkening of color is most noticeable in the tail and ears when compared to mice homozygous for pearl 11 Jackson (pe-11J). Both homozygous males and females breed and live a normal lifespan. The breeding levels of mice carrying the Ap3b1pe-14J mutation are below normal, but are comparable to the breeding levels of the B10.R111H2+H2T18b/(7INS)Sn-Ap3b1pe-11J/+ /J strain.
Genetic Analysis
In order to determine the mode of inheritance, a female, homozygous for this new mutation, was mated to an unrelated C56BL/6J male. No affected offspring were observed in the F1 generation produced from this mating. Mice from this F1 generation were then mated together to produce F2s and in this cross both affected and unaffected animals were produced showing that the mutation is recessive.
A direct test for allelism was set up by mating a female homozygous for the new mutation to a male homozygous for Ap3b1-pe-11J. This mating produced 2 litters in which all offspring were affected (13/13 animals), proving the new mutation to be an allele of Ap3b1-pe. The Ap3b1pe gene is located at the 47 cM position on Mouse Chromosome 13 (MGD).
Pathology
A routine pathological screen done on one homozygous and one heterozygous mouse showed no lesions. The results of auditory brainstem response (ABR) tests showed that a 4 week-old homozygous mutant mouse and a heterozygous littermate both had normal hearing.
The eyes of one homozygous mutant showed severe pigment loss in the peripheral retina, both, when examined by an opthalamscope, and by histological examination. However, the results of a test on the same animal with an electroretinagram (ERG) were normal. The pigment loss in the retina is not unexpected, since pe-14J is a pigment loss mutation.
Acknowledgements
The authors wish to thank Ralph Bernaquer for the discovery of the mutant, Coleen Marden for her excellent technical assistance, and Babette Gwynn for providing the results of the direct test for allelism.
References
Mouse Genome Database (MGD) Mouse Genome Informatics Project, The Jackson Laboratory, Bar Harbor, Maine. World Wide Web
