Vertigo 4 Jackson, a new spontaneous mouse mutation in the Kcnq1 gene.
Leona Gagnon, Leah Davis* and Kenneth R Johnson
Source of Support: This research was supported by NIH/NCRR grant RR01183 to the Mouse Mutant Resource (M.T. Davisson, PI) and NIH/NIDCD grant DC04301 (K.R. Johnson, PI). *Summer Student internship program supported by the National Science Foundation, the Barbara H. Sanford Endowed Scholarship Fund, and the Horace W. Goldsmith
Mutation (allele) symbol: vtg-4J
Mutation (allele) name: vertigo 4 Jackson
Gene symbol: Kcnq1
Strain of origin: NOD/LtJ
Current strain name: B6.NOD-Kcnq1vtg-4J/J
Stock # 006344
Phenotype categories: neurological/behavioral: motor capabilities/coordination/movement anomalies/deafness/head bobbing
Origin and Description
The vertigo 4 Jackson mutation arose spontaneously in the NOD/LtJ inbred strain in 1999. Since mice of the NOD/LtJ inbred strain have significantly elevated auditory brainstem response (ABR) thresholds before three months of age (Zheng et al., 1999), a C57BL/6J congenic line was developed (N=8) creating the current strain, B6.NOD-Kcnq1vtg-4J/J. Mutant mice display head tossing and circling behavior indicative of vestibular dysfunction, and often associated with hearing loss. Four mutant mice and two littermate controls from the congenic line were assessed for hearing by ABR. All mutants from 2-5 months of age were deaf (no response at the highest stimulus presented,100dB) while their control littermates retained good hearing (normal ABR threshold).
Genetic Analysis
An intercross was performed with CAST/Ei and 55 F2 animals were analyzed. Using our standard mapping practice, the mutation was mapped to a region of chromosome 7 where the Kcnq1 gene is located. A complementation test was performed to test for allelism between the new mutation and a known mutation in the Kcnq1 gene, vertigo 2 Jackson (vtg-2J). A heterozygous (+/vtg-2J) female was mated with a mouse homozygous for the new mutation, producing litters yielding a total of 7 pups, 3 of which were mutant, confirming allelism.
Acknowledgements
We thank Bill McKenna for identification of the original mutant mouse and the Deviant Search program at The Jackson Laboratory for bringing the original mutant to our attention. We also thank Chantal Longo-Guess for ABR testing and analysis and Sandra Gray for mouse colony development and maintenance.
References
Zheng QY, Johnson KR, Erway LC (1999) Assessment of hearing in 80 inbred strains of mice by ABR threshold analyses. Hear Res 130: 94-107.
