Expression of basigin, a member of the immunoglobulin superfamily, in the mouse cochlea.

To elucidate the function of basigin (Bsg) in the mouse cochlea, its expression was investigated by reverse-transcription polymerase chain reaction (RT-PCR) and immunohistochemical staining. Amplification by RT-PCR of Bsg-specific primer pairs in total RNA extracted from the mouse cochlea revealed chain reaction products of the expected sizes. Sequence analysis confirmed that the product sequences were identical to sequences in known Bsg fragments. Although Bsg was negative in the capillaries within the cochlea, positive Bsg immunoreactivity was found in the capillaries of the auditory nerve and in the basal cells of the stria vascularis. These findings suggest that Bsg may play an important role in the maintenance of homeostasis, not only of the neural environment in the auditory nerve but also of cochlear fluid.