Mimecan, the 25-kDa corneal keratan sulfate proteoglycan, is a product of the gene producing osteoglycin
Mimecan, the 25-kDa corneal keratan sulfate proteoglycan, is a product of the gene producing osteoglycin
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DOI：
10.1074/jbc.272.44.28089
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发表时间：
1997-10-31
影响因子：
4.8
通讯作者：
Conrad, GW
中科院分区：
文献类型：
--
作者：
Funderburgh, JL;Corpuz, LM;Conrad, GW
牛角膜含有三种独特的硫酸角质素蛋白聚糖（KSPG），其中两种第三种蛋白质（KSPG 25）的基因尚未鉴定。本研究检测了KSPG 25蛋白质与骨甘氨酸基因之间的关系，骨甘氨酸是一种12-kDa的骨糖蛋白，KSPG 25的N端氨基酸序列存在于从牛角膜克隆的骨甘素cDNA中，骨甘素氨基酸序列占KSPG 25蛋白的C端推导序列的47%，骨甘素抗体与完整的角膜KSPG反应，在几种结缔组织中也检测到KSPG 25蛋白和与Lumican和keratocan不同的36-kDa蛋白，未用硫酸角质素修饰的KSPG 25相关蛋白，北方印迹分析显示在许多组织中2.4、2.5和2.6 β-淀粉酶的mRNA转录物，其中2.4 β-淀粉酶转录物在眼组织中富集，核糖核酸酶保护分析检测到几个受保护的KSPG 25 mRNA片段，表明KSPG 25转录物的选择性剪接。我们得出结论，产生骨甘素的基因的全长翻译产物是角膜硫酸角质素蛋白聚糖，也存在于许多不含硫酸角质素链的非角膜组织中，该基因的多种大小的蛋白质产物似乎是由mRNA的原位蛋白水解加工和/或选择性剪接引起的，该基因及其产物被命名为mimecan。
Bovine cornea contains three unique keratan sulfate proteoglycans (KSPGs), of which two (lumican and keratocan) have been characterized using molecular cloning, The gene for the third protein (KSPG25) has not been identified, This study examined the relationship between the KSPG25 protein and the gene for osteoglycin, a 12-kDa bone glycoprotein, The N-terminal amino acid sequence of KSPG25 occurs in osteoglycin cDNA cloned from bovine cornea, The osteoglycin amino acid sequence makes up the C-terminal 47% of the deduced sequence of the KSPG25 protein, Antibodies to osteoglycin reacted with intact corneal KSPG, with KSPG25 protein, and with a 36-kDa protein, distinct from lumican and keratocan, KSPG25-related proteins, not modified with keratan sulfate, were also detected in several connective tissues, Northern blot analysis showed mRNA transcripts of 2.4, 2.5, and 2.6 kilobases in numerous tissues with the 2.4-kilobase transcript enriched in ocular tissues, Ribonuclease protection analysis detected several protected KSPG25 mRNA fragments, suggesting alternate splicing of KSPG25 transcripts, We conclude that the full-length translation product of the gene producing osteoglycin is a corneal keratan sulfate proteoglycan, also present in many non-corneal tissues without keratan sulfate chains, The multiple size protein products of this gene appear to result from ia situ proteolytic processing and/or alternative splicing of mRNA, The name mimecan is proposed for this gene and its products.