Molecular structure, chromosome assignment, and promoter organization of the human matrix Gla protein gene.
Molecular structure, chromosome assignment, and promoter organization of the human matrix Gla protein gene.
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DOI：
10.1016/s0021-9258(18)77221-9
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发表时间：
1990-09
期刊：
影响因子：
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通讯作者：
Leonor CancelaS;Chih-Lin Hsiehg;Uta Francket;Paul A. PriceSV
中科院分区：
文献类型：
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作者：
Leonor CancelaS;Chih-Lin Hsiehg;Uta Francket;Paul A. PriceSV
基质GLA蛋白(MGP)是一种最初从牛骨中分离出来的84个残基的维生素K依赖蛋白。MGP在心脏、肾脏和肺中也有高水平的表达，并在骨细胞中受到维生素D的上调。为了鉴定与该基因调控表达有关的基因组序列，我们使用MGP基因探针对人类基因组文库进行了筛选，获得了两个含有MGP基因的克隆。人类MGP基因全长3.9kb，由四个外显子组成，由三个大的插入序列隔开，占该基因的80%以上。对人类基因组DNA的Southern分析表明，MGP基因只有一个拷贝。将HMGP基因与一系列中国仓鼠×人杂交克隆杂交，将该基因定位于人12号染色体的短臂(12P)。已知的依赖维生素K的脊椎动物蛋白质的N-末端序列显示一个跨膜信号肽，紧随其后的是一个假定的伽玛-羧化识别位点和一个含有GLA的结构域。这些区域中的每一个都对应于MGP中的一个单独的外显子。MGP还含有第四个未知功能的外显子，它编码11个残基，位于跨膜信号肽和伽马-羧基酶的假定识别位点之间。这种四外显子结构与骨GLA蛋白的结构基本相同，与其他已知的维生素K依赖蛋白中编码这一区域的两个外显子组织有很大的不同。对MGP基因启动子的分析表明，除了典型的TATA和CAT盒外，还存在一些与先前发现的激素和转录因子反应元件同源的假定调控序列。特别是，描述了启动子的两个区域，其中包含可能与维甲酸和维生素D受体结合的位置。
Matrix Gla protein (MGP) is an 84-residue vitamin K-dependent protein initially isolated from bovine bone. MGP is also expressed at high levels in heart, kidney, and lung and is up-regulated by vitamin D in bone cells. To characterize the genomic sequences responsible for the regulated expression of this gene, we screened a human genomic library using a MGP cDNA probe and obtained two clones containing the MGP locus. The human MGP gene spans 3.9 kilobases of chromosomal DNA and consists of four exons separated by three large intervening sequences which account for more than 80% of the gene. Southern analysis of total human genomic DNA indicated the presence of a single copy of the MGP gene. Hybridization of the hMGP cDNA to a series of Chinese Hamster x human hybrid clones assigned this gene to the short arm of the human chromosome 12 (12p). The N-terminal sequences of the known vitamin K-dependent vertebrate proteins reveal a transmembrane signal peptide, followed by a putative gamma-carboxylation recognition site and a Gla-containing domain. Each of these regions correspond to a separate exon in MGP. MGP also contains a fourth exon of unknown function which codes for 11 residues and lies between the transmembrane signal peptide and the putative recognition site for the gamma-carboxylase. This four-exon organization is essentially identical to that of bone Gla protein and is quite different from the two exon organization encoding this region in the other known vitamin K-dependent proteins. Analysis of the MGP gene promoter revealed, in addition to the typical TATA and CAT boxes, the presence of a number of putative regulatory sequences homologous to previously identified hormone and transcription factor responsive elements. In particular, two regions of the promoter were delineated containing possible binding sites for retinoic acid and vitamin D receptors.