[Application of non-radioisotopic in situ hybridization to the inner ear--expression of osteopontin].
Osteopontin (OPN) is considered to be a non-collagenous bone matrix protein which is involved in the ossification process. However, OPN has recently been observed in ectopic sites such as the kidney and nervous tissues. In the present study, expression of OPN mRNA was examined in the rat inner ear by non-radioisotopic in situ hybridization. Signals of OPN mRNA were observed in the marginal cells of the stria vascularis, spiral ganglions, vestibular sensory hair cells and vestibular dark cells. OPN protein was detected only in otoliths by immunohistochemistry. The reasons for the presence of OPN mRNA in the cochlea and dark cells of the vestibulum were unclear. On the other hand, findings of the sacculus and utriculus suggest that OPN is one of the protein components of rat otoliths and that vestibular sensory hair cells are involved in the production of otoliths.
Sakagami
M
M
Department of Otolaryngology, Osaka University Medical School.
Takemura
T
T
Umemoto
M
M
Kubo
T
T
D000818:Animals; D007758:Ear, Inner / Q000737:chemistry*; D017403:In Situ Hybridization / Q000379:methods*; D053495:Osteopontin; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D012795:Sialoglycoproteins / Q000032:analysis* / Q000235:genetics
D012333:RNA, Messenger; D012795:Sialoglycoproteins; C506897:Spp1 protein, rat; D053495:Osteopontin