Tezuka K, Tezuka Y, Maejima A, Sato T, Nemoto K, Kamioka H, Hakeda Y, Kumegawa M
Department of Oral Anatomy, Meikai University School of Dentistry, Saitama, Japan.
J Biol Chem. 1994 Jan 14;269(2):1106-9.
Osteoclasts are multinucleate giant cells playing key roles in bone resorption. These cells solubilize mineralized bone matrix by means of acid and protease action; however, the precise mechanism of this process is not well known. Recently, we succeeded in the isolation of pure osteoclasts from rabbit bones and constructed a cDNA library. Using a differential screening procedure, two genes expressed predominantly in osteoclasts compared with spleen cells were isolated (Tezuka, K., Sato, T., Kamioka, H., Nijweide, P. J., Tanaka, K., Matsuo, T., Ohta, M., Kurihara, N., Hakeda, Y., and Kumegawa, M. (1992) Biochem. Biophys. Res. Commun. 186, 911-917). One of them, OC-2, was found to encode a possible cysteine proteinase structurally related to cathepsins L and S. By in situ hybridization, OC-2 was confirmed to be expressed in osteoclasts in vivo. By Northern blot analysis, OC-2 was highly and preferentially expressed in osteoclasts compared with other tissues such as kidney, liver, spleen, and lung. The predominant expression of OC-2 in osteoclasts may suggest that OC-2 encodes a protein, possibly a cysteine proteinase, that plays an important role in osteoclastic bone resorption.
破骨细胞是在骨吸收中起关键作用的多核巨细胞。这些细胞通过酸和蛋白酶的作用使矿化的骨基质溶解；然而，这一过程的确切机制尚不清楚。最近，我们成功地从兔骨中分离出了纯破骨细胞，并构建了一个cDNA文库。通过差异筛选程序，分离出了两个与脾细胞相比在破骨细胞中主要表达的基因（手冢，K.，佐藤，T.，神冈，H.，尼杰维德，P.J.，田中，K.，松尾，T.，太田，M.，栗原，N.，哈克达，Y.，和久米川，M.（1992年）生物化学与生物物理研究通讯186，911 - 917）。其中一个基因，OC - 2，被发现编码一种可能的半胱氨酸蛋白酶，其结构与组织蛋白酶L和S相关。通过原位杂交，证实OC - 2在体内破骨细胞中表达。通过Northern印迹分析，与肾、肝、脾和肺等其他组织相比，OC - 2在破骨细胞中高度且优先表达。OC - 2在破骨细胞中的主要表达可能表明OC - 2编码一种蛋白质，可能是一种半胱氨酸蛋白酶，在破骨细胞性骨吸收中起重要作用。
