Identification of a novel isoform of mouse dentin matrix protein 1: Spatial expression in mineralized tissues
Identification of a novel isoform of mouse dentin matrix protein 1: Spatial expression in mineralized tissues
复制标题
DOI：
10.1359/jbmr.1998.13.3.422
复制
发表时间：
1998-03-01
影响因子：
6.2
通讯作者：
Chen, JK
中科院分区：
文献类型：
--
作者：
MacDougall, M;Gu, TT;Chen, JK
牙本质基质蛋白1（Dentin matrix protein 1，Dmp 1）是一种酸性磷酸化蛋白，首次从大鼠牙体文库中克隆得到，北方印迹杂交显示Dmp 1仅在成牙本质细胞中表达，提示Dmp 1是成牙本质细胞特异性的。原位杂交研究表明Dmp 1在成牙本质细胞中表达，在分泌型成釉细胞中瞬时表达。本研究的目的是分离和鉴定小鼠Dmp 1 cDNA，并确定其与其他矿化组织相关的空间表达模式。对最大的小鼠Dmp 1 cDNA（2802个碱基对[bp]）的DNA序列分析揭示了1509个核苷酸的开放阅读框架，其编码具有单个多聚腺苷酸化信号的503个氨基酸的蛋白质。与大鼠和牛的Dmp 1序列比较，同源性较高，通过对小鼠基因组Dmp 1克隆的DNA分析，显示该45 bp片段代表小外显子。原位杂交研究显示Dmp 1组织表达模式比以前报道的广泛得多，在成牙本质细胞和成釉细胞、成骨细胞和成牙骨质细胞中检测到dmp 1转录本。我们的数据表明，Dmp 1是选择性剪接，和主要的全长转录包含一个45 bp的插入，这是由一个小的外显子编码，因此，Dmp 1不是牙齿特异性蛋白，而是在许多矿化组织，包括牙釉质，骨，牙骨质中表达。
Dentin matrix protein 1 (Dmp1) is apr acidic phosphoprotein first identified by cDNA cloning from a rat tooth library, Northern blot hybridization of a variety of tissues detected Dmp1 mRNAs only in odontoblasts, suggesting that this protein was odontoblast specific. In situ hybridization studies showed expression of Dmp1 in odontoblasts with transient expression in secretory ameloblasts, The purpose of this study was to isolate and characterize a mouse Dmp1 cDNA and determine its spatial expression pattern related to other mineralizing tissues, A mouse molar cDNA library was screened with a P-32-labeled Dmp1 polymerase chain reaction amplification product in order to isolate a full-length clone, DNA sequence analysis of the largest mouse Dmp1 cDNA (2802 base pairs [bp]) revealed an open reading frame of 1509 nucleotides encoding a 503 amino acid protein with a single polyadenylation signal. Comparison with rat and bovine Dmp1 sequence showed high homolog and the identification of a 45 bp (15 amino acid) insert, representing an alternative spliced mRNA, This 45 bp segment was shown to represent a small exon by DNA analysis of a mouse genomic Dmp1 clone, In situ hybridization studies revealed a much broader Dmp1 tissue expression pattern than previously reported, Dmp1 transcripts were detected in the odontoblast and ameloblasts, osteoblasts, and cementoblasts. Our data indicate that Dmp1 is alternatively spliced, and the primary full-length transcript contains a 45 bp insert which is encoded by a small exon, Therefore, Dmp1 is not a tooth-specific protein but rather is expressed in a number of mineralizing tissues including enamel, bone, and cementum.