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

This article describes a new recessive insertional mutation in the transgen ic line TgN2742Rpw that causes deafness and circling behavior in mice. Hist ologic analysis revealed virtually complete loss of the cochlear neuroepith elium (the organ of Corti) in adult mutant mice. In association with the ne uroepithelial changes, there is a dramatic reduction of the cochlear nerve supply. Adult mutants also show morphological defects of the vestibular app aratus, including degeneration of the saccular neuroepithelium and occasion al malformation of utricular otoconia. Audiometric evaluations demonstrated that the mice displaying the circling phenotype are completely deaf. Molec ular analysis of this mutant line revealed that the transgenic insertion oc curred without creating a large deletion of the host DNA sequences. The mut ant locus was mapped to a region on mouse chromosome 10, where other sponta neous, recessive mutations causing deafness in mice have been mapped.