Altered glycosylated PrP proteins can have different neuronal trafficking in brain but do not acquire scrapie-like properties
Altered glycosylated PrP proteins can have different neuronal trafficking in brain but do not acquire scrapie-like properties
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DOI：
10.1074/jbc.m509557200
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发表时间：
2005-12-30
影响因子：
4.8
通讯作者：
Manson, JC
中科院分区：
文献类型：
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作者：
Cancellotti, E;Wiseman, F;Manson, JC
n -链聚糖已被证明在多种细胞表面糖蛋白（包括PrP蛋白）的细胞生物学中具有重要作用。有人认为，PrP的糖基化可以影响对传染性海绵状脑病的易感性，并决定在这种特殊类型的疾病中观察到的许多不同菌株的特征。为了了解碳水化合物在影响PrP成熟、稳定性和细胞生物学中的作用，我们制作并分析了表达差异糖基化PrP的基因靶向小鼠模型。通过双置换基因靶向，分别产生了去除第一个、第二个和两个糖基化位点的PrP替代苏氨酸代替天冬酰胺180 （G1）或苏氨酸代替天冬酰胺196 （G2）或两种突变组合（G3）的转基因小鼠。我们在转基因小鼠大脑中对改变后的PrP进行了体内分析，我们的数据表明，缺乏聚糖并不影响PrP的成熟和稳定性。一条糖链的存在足以运输到细胞膜，而未糖基化的PrP定位主要在细胞内。然而，这种PrP的细胞定位改变不会导致G3转基因小鼠出现任何明显的表型。最重要的是，我们发现，在体内，未糖基化的PrP没有获得异常致病形式（PrPSc）的特征，正如之前在体外模型中报道的那样。
N-Linked glycans have been shown to have an important role in the cell biology of a variety of cell surface glycoproteins, including PrP protein. It has been suggested that glycosylation of PrP can influence the susceptibility to transmissible spongiform encephalopathy and determine the characteristics of the many different strains observed in this particular type of disease. To understand the role of carbohydrates in influencing the PrP maturation, stability, and cell biology, we have produced and analyzed gene-targeted murine models expressing differentially glycosylated PrP. Transgenic mice carrying the PrP substitution threonine for asparagine 180 (G1) or threonine for asparagine 196 (G2) or both mutations combined (G3), which eliminate the first, second, and both glycosylation sites, respectively, have been generated by double replacement gene targeting. An in vivo analysis of altered PrP has been carried out in transgenic mouse brains, and our data show that the lack of glycans does not influence PrP maturation and stability. The presence of one chain of sugar is sufficient for the trafficking to the cell membrane, whereas the unglycosylated PrP localization is mainly intracellular. However, this altered cellular localization of PrP does not lead to any overt phenotype in the G3 transgenic mice. Most importantly, we found that, in vivo, unglycosylated PrP does not acquire the characteristics of the aberrant pathogenic form (PrPSc), as was previously reported using in vitro models.