Tezuka K, Sato T, Kamioka H, Nijweide P J, Tanaka K, Matsuo T, Ohta M, Kurihara N, Hakeda Y, Kumegawa M
Department of Oral Anatomy, Meikai University School of Dentistry, Sakado, Japan.
Biochem Biophys Res Commun. 1992 Jul 31;186(2):911-7. doi: 10.1016/0006-291x(92)90832-6.
Bone remodeling is a complex process coupling bone formation and resorption. Osteoblasts, the bone-forming cells, are known to produce various bone matrix proteins and cytokines; however, little is known about protein factors produced by osteoclasts or bone-resorbing cells. A method utilizing the high affinity of osteoclasts for tissue culture dishes was developed to isolate a large number of pure osteoclasts from rabbit long bones. A cDNA library was then constructed from these isolated osteoclasts, and differential cDNA screening was performed between osteoclasts and spleen cells. Two clones representing osteoclast-specific clones, named OC-1 and OC-2, were isolated. By Northern blot analysis, OC-1 was expressed in osteoclasts and in kidneys, whereas OC-2 was specific for osteoclasts. OC-1 was found to encode osteopontin from its nucleotide sequence, and therefore, osteopontin may have other functions for osteoclastic bone resorption besides osteoclast attachment to bone.
