Propagation of RML prions in mice expressing PrP devoid of GPI anchor leads to formation of a novel, stable prion strain.
Propagation of RML prions in mice expressing PrP devoid of GPI anchor leads to formation of a novel, stable prion strain.
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DOI：
10.1371/journal.ppat.1002746
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发表时间：
2012
期刊：
影响因子：
6.7
通讯作者：
Weissmann C
中科院分区：
文献类型：
--
作者：
Mahal SP;Jablonski J;Suponitsky-Kroyter I;Oelschlegel AM;Herva ME;Oldstone M;Weissmann C
PrPC是一种宿主蛋白，在朊病毒感染的动物体内转化为PrPSc，通过GPI锚点连接到细胞膜上。表达无GPI锚定PrPC的小鼠（tgGPI-小鼠）易受朊病毒感染，但在细胞外而不是细胞内积累无锚定PrPSc。我们研究了尽管锚定PrPSc的结构和位置偏离，tgGPI -小鼠是否能忠实地传播朊病毒菌株。我们发现RML和ME7，而不是22L朊病毒在tgGPI−大脑中传播，通过细胞面板试验（CPA）确定了新的细胞倾向。令人惊讶的是，在RML-或me7感染的tgGPI -脑组织中，蛋白酶k抗性PrPSc （PrPres）水平比野生型脑组织高25-50倍。当ME7朊病毒返回野生型小鼠大脑时，ME7朊病毒恢复了其原有的特性，而RML朊病毒产生了一种新的朊病毒株，称为SFL，即使在野生型小鼠中传代三次也没有改变。由于RML PrPSc和SFL PrPSc在野生型小鼠中都能稳定地传播，我们认为这两种构象被一个高活化能垒分开，而在tgGPI -小鼠中则被消除了。引起传染性海绵状脑病的朊病毒主要由PrPSc （PrPC的聚集构象变体）组成。PrPC是一种宿主特有的糖蛋白，通过糖基磷脂酰肌醇（GPI）锚点附着在质膜的外表面。PrPSc被认为是通过种子转化传播的，在种子转化中，PrPC聚集成PrPSc的集合体，从而具有其构象。朊病毒以不同的菌株出现，它们具有相同的PrP序列，但PrPSc构象不同。许多菌株非常稳定，但有些可能“突变”，特别是在另一动物物种中短暂繁殖后。这里的“突变”归因于潜在的PrPSc蛋白的构象变化，而不是基因核苷酸序列的变化。在表达无锚定PrP的转基因小鼠中，向PrPSc的转化发生在细胞外，而不是在细胞相关的隔室中。令人惊讶的是，RML是一种非常稳定的朊病毒菌株，当在tgGPI -小鼠中传播并返回到野生型小鼠时，它被恢复为一种新的菌株，称为SFL，它在许多传播中都是稳定的。因此，由于修饰的PrP或由于tgGPI -脑细胞外区不同的复制模式，忠实的菌株繁殖被取消。
PrPC, a host protein which in prion-infected animals is converted to PrPSc, is linked to the cell membrane by a GPI anchor. Mice expressing PrPC without GPI anchor (tgGPI- mice), are susceptible to prion infection but accumulate anchorless PrPSc extra-, rather than intracellularly. We investigated whether tgGPI− mice could faithfully propagate prion strains despite the deviant structure and location of anchorless PrPSc. We found that RML and ME7, but not 22L prions propagated in tgGPI− brain developed novel cell tropisms, as determined by the Cell Panel Assay (CPA). Surprisingly, the levels of proteinase K-resistant PrPSc (PrPres) in RML- or ME7-infected tgGPI− brain were 25–50 times higher than in wild-type brain. When returned to wild-type brain, ME7 prions recovered their original properties, however RML prions had given rise to a novel prion strain, designated SFL, which remained unchanged even after three passages in wild-type mice. Because both RML PrPSc and SFL PrPSc are stably propagated in wild-type mice we propose that the two conformations are separated by a high activation energy barrier which is abrogated in tgGPI− mice. The agent causing transmissible spongiform encephalopathies, the prion, consists mainly if not entirely of PrPSc, an aggregated conformational variant of PrPC. PrPC is a host-specified glycoprotein which is attached to the outer surface of the plasma membrane by a glycosylphosphatidylinositol (GPI) anchor. PrPSc is thought to propagate by seeded conversion, in which PrPC accretes to an aggregate of PrPSc and thereby assumes its conformation. Prions occur as distinct strains, which have the same PrP sequence but different PrPSc conformations. Many strains are very stable but some can “mutate”, especially after transient propagation in another animal species. Here “mutation” is attributed to a conformational change of the underlying PrPSc protein rather than a change in the nucleotide sequence of a gene. In transgenic mice that express anchorless PrP, conversion to PrPSc occurs extracellularly rather than in a cell-associated compartment. Surprisingly, RML, a very stable prion strain, when propagated in tgGPI− mice and then returned to wild-type mice, was recovered as a novel strain, designated SFL, which was stable over many transmissions. Thus, faithful strain propagation was abrogated either as a consequence of the modified PrP or because of a different replication mode in the extracellular compartment of tgGPI− brain.
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影响因子：
5.4
作者：
Cancellotti, Enrico;Bradford, Barry M.;Manson, Jean C.
通讯作者：
Manson, Jean C.
影响因子：
0.8
作者：
FRASER, H;DICKINSON, AG
通讯作者：
DICKINSON, AG
影响因子：
6.7
作者：
Chesebro B;Race B;Meade-White K;Lacasse R;Race R;Klingeborn M;Striebel J;Dorward D;McGovern G;Jeffrey M
通讯作者：
Jeffrey M
DOI：
10.1038/nrmicro2650
发表时间：
2011-09-26
期刊：
Nature reviews. Microbiology
影响因子：
--
作者：
通讯作者：
--
影响因子：
5.4
作者：
Bosque, PJ;Prusiner, SB
通讯作者：
Prusiner, SB