Department of Biomedical Sciences, Baylor College of Dentistry, Texas A & M University System Health Science Center, Dallas, TX, USA.
Int J Oral Maxillofac Surg. 2010 Mar;39(3):272-81. doi: 10.1016/j.ijom.2009.12.017. Epub 2010 Jan 25.
The Small Integrin-Binding LIgand, N-linked Glycoprotein (SIBLING) family is one category of non-collagenous proteins closely related to osteogenesis. In this study, the authors systematically evaluated the presence and distribution of four SIBLING family members, dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), bone sialoprotein (BSP) and osteopontin (OPN), in rat mandibular condylar cartilage using protein chemistry and immunohistochemistry. For protein chemistry, SIBLING proteins in the dissected condylar cartilage were extracted with 4M guanidium-HCl, separated by ion-exchange chromatography, and analyzed by Western immunoblotting. Immunohistochemistry was employed to assess the distribution of these four SIBLING proteins in the condylar cartilage of 2-, 5- and 8-week-old rats. Results from both approaches showed that all four members are expressed in the condylar cartilage. DSPP, unlike that observed in dentin and bone, exists as a full-length form (uncleaved) in the condylar cartilage. The NH(2)-terminal fragment of DMP1 is mainly detected in the matrix of the cartilage while the COOH-terminal fragment is primarily localized in the nuclei of cells in the chondroblastic and hypertrophic layers. The data obtained in this investigation provide clues about the potential roles of these SIBLING proteins in chondrogenesis.
小整合素结合的 Ligand，N-连接糖蛋白（SIBLING）家族是一类与成骨密切相关的非胶原蛋白。在这项研究中，作者使用蛋白质化学和免疫组织化学方法系统地评估了四个 SIBLING 家族成员，牙本质涎磷蛋白（DSPP）、牙本质基质蛋白 1（DMP1）、骨涎蛋白（BSP）和骨桥蛋白（OPN）在大鼠下颌髁状突软骨中的存在和分布。对于蛋白质化学，用 4M 盐酸胍提取分离的髁状突软骨中的 SIBLING 蛋白，用离子交换色谱分离，并通过 Western 免疫印迹进行分析。免疫组织化学用于评估这四个 SIBLING 蛋白在 2、5 和 8 周龄大鼠髁状突软骨中的分布。两种方法的结果均表明，所有四个成员都在髁状突软骨中表达。与牙本质和骨中观察到的不同，DSPP 以全长形式（未切割）存在于髁状突软骨中。DMP1 的 NH2-末端片段主要存在于软骨基质中，而 COOH-末端片段主要定位于软骨细胞层和肥大层的细胞核中。本研究获得的数据为这些 SIBLING 蛋白在软骨发生中的潜在作用提供了线索。
