A new mouse insertional mutation that causes sensorineural deafness and vestibular defects.

This article describes a new recessive insertional mutation in the transgenic line TgN2742Rpw that causes deafness and circling behavior in mice. Histologic analysis revealed virtually complete loss of the cochlear neuroepithelium (the organ of Corti) in adult mutant mice. In association with the neuroepithelial changes, there is a dramatic reduction of the cochlear nerve supply. Adult mutants also show morphological defects of the vestibular apparatus, including degeneration of the saccular neuroepithelium and occasional malformation of utricular otoconia. Audiometric evaluations demonstrated that the mice displaying the circling phenotype are completely deaf. Molecular analysis of this mutant line revealed that the transgenic insertion occurred without creating a large deletion of the host DNA sequences. The mutant locus was mapped to a region on mouse chromosome 10, where other spontaneous, recessive mutations causing deafness in mice have been mapped.