Identification of full-length dentin matrix protein 1 in dentin and bone
Identification of full-length dentin matrix protein 1 in dentin and bone
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DOI：
10.1007/s00223-008-9140-7
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发表时间：
2008-05-01
影响因子：
4.2
通讯作者：
Qin, Chunlin
中科院分区：
文献类型：
--
作者：
Huang, Bingzhen;Maciejewska, Izabela;Qin, Chunlin
牙本质基质蛋白1 （DMP1）在牙本质和骨的细胞外基质（ECM）中被鉴定为加工过的nh2末端和cooh末端片段。然而，在这些组织中尚未发现DMP1的全长形式。本研究的重点是在牙本质和骨中寻找完整的全长DMP1。我们使用两种类型的抗DMP1抗体来鉴定DMP1：一种类型特异性识别nh2末端区域，另一种类型仅对DMP1氨基酸序列的cooh末端区域起反应。从大鼠牙本质和骨的ECM中提取的一种类似于105-kDa的蛋白被两种抗体识别；该蛋白的迁移速率与真核细胞中制备的重组小鼠全长DMP1相同。我们得出结论，这种类似于105-kDa的蛋白是DMP1的全长形式，其在牙本质和骨的ECM中的丰度远远低于其加工片段。我们还在大鼠牙髓/成牙细胞复合体提取物中检测到DMP1的全长形式及其加工片段。此外，免疫荧光分析显示，在MC3T3-E1细胞中，DMP1的nh2端和cooh端片段分布不同。我们的研究结果表明，大多数DMP1必须在合成它的细胞内被切割，少量未被切割的DMP1分子被分泌到牙本质和骨的ECM中。
Dentin matrix protein 1 (DMP1) has been identified in the extracellular matrix (ECM) of dentin and bone as the processed NH2-terminal and COOH-terminal fragment. However, the full-length form of DMP1 has not been identified in these tissues. The focus of this investigation was to search for the intact full-length DMP1 in dentin and bone. We used two types of anti-DMP1 antibodies to identify DMP1: one type specifically recognizes the NH2-terminal region and the other type is only reactive to the COOH-terminal region of the DMP1 amino acid sequence. An similar to 105-kDa protein, extracted from the ECM of rat dentin and bone, was recognized by both types of antibodies; and the migration rate of this protein was identical to the recombinant mouse full-length DMP1 made in eukaryotic cells. We concluded that this similar to 105-kDa protein is the full-length form of DMP1, which is considerably less abundant than its processed fragments in the ECM of dentin and bone. We also detected the full-length form of DMP1 and its processed fragments in the extract of dental pulp/odontoblast complex dissected from rat teeth. In addition, immunofluorescence analysis showed that in MC3T3-E1 cells the NH2-terminal and COOH-terminal fragments of DMP1 are distributed differently. Our findings indicate that the majority of DMP1 must be cleaved within the cells that synthesize it and that minor amounts of uncleaved DMP1 molecules are secreted into the ECM of dentin and bone.