Molecular cloning and characterization of rat Pomt1 and Pomt2.
Molecular cloning and characterization of rat Pomt1 and Pomt2.
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DOI：
10.1093/glycob/cwl002
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发表时间：
2006-09
期刊：
影响因子：
4.3
通讯作者：
H. Manya;A. Chiba;R. U. Margolis;T. Endo
中科院分区：
文献类型：
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作者：
H. Manya;A. Chiba;R. U. Margolis;T. Endo
哺乳动物的O-甘露糖化虽然是一种不常见的蛋白质修饰，但对正常的大脑和肌肉发育是必不可少的。O-甘露醇合成缺陷导致先天性肌营养不良伴神经元异常迁移[Walker-Warburg综合征(WWS)]。在此，我们鉴定并克隆了大鼠POMT1和POMT2，它们是人POMT1和POMT2的同源物，在氨基酸水平上的同源性分别为86%和90%。研究发现，这两个基因的共同表达对于酶的活性是必要的，就像人类POMT1和POMT2一样。Northern印迹和逆转录聚合酶链式反应(RT-PCR)分析表明，大鼠Pomt1和Pomt2在所有组织中都有表达，但以睾丸表达最强。大鼠脑的原位杂交组织化学显示，Pomt1和Pomt2在神经元(海马齿状回、CA1-CA3区和小脑浦肯野细胞)中共表达。在大鼠Pomt2中观察到两个转录起始点，导致两种形式：睾丸形式和体细胞形式。当两种形式与大鼠Pomt1共表达时，具有相同的蛋白O-甘露糖基转移酶活性。共表达研究还表明，人和大鼠的蛋白O-甘露糖基转移酶是可以互换的，这为它们的结构接近提供了进一步的证据。
Mammalian O-mannosylation, although an uncommon type of protein modification, is essential for normal brain and muscle development. Defective O-mannosylation causes congenital muscular dystrophy with abnormal neuronal migration [Walker-Warburg syndrome (WWS)]. Here, we have identified and cloned rat Pomt1 and Pomt2, which are homologues of human POMT1 and POMT2, with identities of 86 and 90%, respectively, at the amino acid level. Coexpression of both genes was found to be necessary for enzymatic activity, as is the case with human POMT1 and POMT2. Northern blot and reverse transcriptase polymerase chain reaction (RT-PCR) analyses revealed that rat Pomt1 and Pomt2 are expressed in all tissues but most strongly in testis. In situ hybridization histochemistry of rat brain revealed that Pomt1 and Pomt2 mRNA are coexpressed in neurons (dentate gyrus and CA1-CA3 region of the hippocampus and cerebellar Purkinje cells). Two transcription-initiation sites were observed in rat Pomt2, resulting in two forms: a testis form and a somatic form. The two forms had equal protein O-mannosyltransferase activity when coexpressed with rat Pomt1. Coexpression studies also showed that the human and rat protein O-mannosyltransferases are interchangeable, providing further evidence for the closeness of their structures.