Homozygous mice are viable and fertile. The donating investigator reports a dramatic loss of fecundity after 5-6 months of age. The targeting vector contains an endoplasmic reticulum (ER) retention signal (KDEL), which is reported to sequester the potential truncated mRNA product in the ER. The vector also contains an IRES-PLAP reporter gene, allowing extracellular antibody staining/chromogenic development tracking of cells normally expressing the endogenous gene. Homozygous mice display behavioral deficits in response to mustard oil, cold, and punctate mechanical stimuli. These mice have a normal startle reflex to loud noise, a normal sense of balance, a normal auditory brainstem response, and normal transduction currents in vestibular hair cells. These mutants may be useful in neurobiological studies involving dorsal root ganglion neurons and cells of the inner ear, as well as for auditory, temperature, or chemical irritant trials. The Jackson Laboratory 2024, used with permission.