The mouse slalom mutant demonstrates a role for Jagged1 in neuroepithelialpatterning in the organ of Corti

The Notch signalling pathway has recently been implicated in the developmen t and patterning of the sensory epithelium in the cochlea, the organ of Cor ti. As part of an ongoing large-scale mutagenesis programme to identify new deaf or vestibular mouse mutants, we have identified a novel mouse mutant, slalom, which shows abnormalities in the patterning of hair cells in the o rgan of Corti and missing ampullae, structures that house the sensory epith elia of the semicircular canals. We show that the slalom mutant carries a m utation in the Jagged1 gene, implicating a new ligand in the signalling pro cesses that pattern the inner ear neuro-epithelium.