Purification of neuronal inclusions of patients with Huntington's disease reveals a broad range of N-terminal fragments of expanded huntingtin and insoluble polymers
Purification of neuronal inclusions of patients with Huntington's disease reveals a broad range of N-terminal fragments of expanded huntingtin and insoluble polymers
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DOI：
10.1111/j.1471-4159.2005.03348.x
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发表时间：
2005-10-01
影响因子：
4.7
通讯作者：
Djian, P
中科院分区：
文献类型：
--
作者：
Hoffner, G;Island, ML;Djian, P
由含有扩增的多聚谷氨酰胺的亨廷顿蛋白引起的亨廷顿病与主要局限于神经元内含物的聚集体和神经元死亡有关。包涵体被认为来源于由特异性内肽酶产生的扩展亨廷顿蛋白的离散N-末端片段。我们现在已经纯化了亨廷顿病脑的神经元内含物。当在浓甲酸中孵育时，纯化的包涵体释放出一种聚合物、一种寡聚物和广泛的扩展亨廷顿蛋白的N-末端片段。片段和聚合物形式通过非共价键彼此连接，因为它们都被甲酸释放，而聚合物形式本身可能通过共价键稳定，因为它们对甲酸具有抗性。我们还证明了存在于大脑的受影响区域，但不是在未受影响的地区的广泛的可溶性N-末端片段的扩展亨廷顿蛋白尚未与夹杂物，这是可能的夹杂物的前体。在亨廷顿病中，扩增的亨廷顿蛋白的片段化必定是由于具有很少特异性的多种蛋白水解活性的作用，而不是由于特定的内肽酶的作用;随后通过共价键和非共价键的片段的聚集导致内含物的形成。
Huntington's disease resulting from huntingtin containing an expanded polyglutamine is associated with aggregates largely confined to neuronal inclusions, and with neuronal death. Inclusions are thought to originate from discrete N-terminal fragments of expanded huntingtin produced by specific endopeptidases. We have now purified the neuronal inclusions of Huntington's disease brain. When incubated in concentrated formic acid, purified inclusions release a polymer, an oligomer and a broad range of N-terminal fragments of expanded huntingtin. The fragments and the polymeric forms are linked to each other by non-covalent bonds as they are both released by formic acid, whereas the polymeric forms themselves are presumably stabilized by covalent bonds, as they are resistant to formic acid. We also demonstrate the presence in affected areas of the brain but not in unaffected areas of a broad range of soluble N-terminal fragments of expanded huntingtin not yet associated with the inclusions and which are likely to be the precursors of the inclusions. Fragmentation of expanded huntingtin in Huntington's disease must result from the operation of multiple proteolytic activities with little specificity and not from that of a specific endopeptidase; subsequent aggregation of the fragments by covalent and non-covalent bonds leads to the formation of the inclusions.