B6;129S4-Ush1c^dfcr-2J/J

Stock number: 004768
Product name: deaf circler 2 Jackson
Research areas: Mouse/Human Gene Homologs, Neurobiology Research, Sensorineural Research

Description

These mice carry a spontaneous mutation at the Ush1c locus characterized by head tossing, hyperactive circling, and disorientation in water.

Detailed description

Mice homozygous for either Ush1c^dfcr or Ush1c^dfcr-2J display head tossing and hyperactive circling. They are unable to orient themselves in water to swim at the surface. Despite these behavioral traits, these mice are able to breed and have normal life spans. Adult homozygotes have no auditory-evoked brainstem response. This complete deafness was found in an Ush1c^dfcr homozygote as early as 21 days of age. Scanning electron micrographs of the organ of Corti at 3 weeks of age reveal disorganized and splayed stereocilia of outer hair cells and, less severely, of inner hair cells along with degeneration of hair cells that yields a disorganized hair cell pattern. While progressive loss of hair cells and a secondary loss of spiral ganglion cells are found and are severe by 8 months of age, no gross morphological abnormalities were discerned in whole mounts of inner ears. At 9 months of age a slight peripheral retinal degeneration is found in mice homozygous for Ush1c^dfcr but not Ush1c^dfcr-2J. These phenotypes have not been identified in mice heterozygous for either allele. (Johnson et al., 2003.)

Development

The dfcr-2J allele of Ush1c arose spontaneously on a mixed background of C57BL/6J and 129S4 in which a targeted mutation of adducin 2 was segregating. The adducin 2 mutation has been bred out of this strain.

Allele

Symbol: Ush1c^dfcr-2J
Name: deaf circler 2 Jackson
MGI accession ID: MGI:2651859
Generation method: Spontaneous
Attributes: Modified isoform(s)
Marker symbol: Ush1c
Marker name: USH1 protein network component harmonin
Chromosome: 7
Strain of origin: B6;129S4-Add2^tm1Llp
Molecular note: The dfcr-2J mutation has been identified as the deletion of a single base pair, the fourth nucleotide in the inner ear-specific exon C of the 28-exon Ush1c gene. This shifts the translational reading frame shift so that 38 incorrect amino acids are incorporated before a premature stop codon is encountered.