PRION PROTEIN-BIOSYNTHESIS IN SCRAPIE-INFECTED AND UNINFECTED NEURO-BLASTOMA CELLS
PRION PROTEIN-BIOSYNTHESIS IN SCRAPIE-INFECTED AND UNINFECTED NEURO-BLASTOMA CELLS
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DOI：
10.1128/jvi.63.1.175-181.1989
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发表时间：
1989-01-01
影响因子：
5.4
通讯作者：
CHESEBRO, B
中科院分区：
文献类型：
--
作者：
CAUGHEY, B;RACE, RE;CHESEBRO, B
大量研究表明，一种经过修饰的蛋白酶 K 抗性形式的内源性脑蛋白朊病毒蛋白 (PrP) 与动物的瘙痒病感染有关。这种与痒病相关的 PrP 修饰似乎发生在大脑中的翻译后，但其分子性质尚不清楚。为了了解正常的 PrP 生物合成以及体外是否会因瘙痒病感染而改变，我们对未感染和感染瘙痒病的小鼠神经母细胞瘤组织培养细胞进行了代谢标记实验。脉冲追踪标记实验表明，在两种细胞类型中，28 和 33 千道尔顿 (kDa) 的两种主要 PrP 前体被加工成成熟的 30-和 35-至 41-kDa 形式。糖苷内切酶 H、衣霉素和磷脂酶处理表明，28-和 33-kDa 前体是由将高甘露糖聚糖添加到含有磷脂酰肌醇部分的 25-kDa 多肽中产生的，并且前体的成熟涉及高甘露糖聚糖向杂合或复合聚糖的转化。用胰蛋白酶和磷脂酰肌醇特异性磷脂酶 C 处理活细胞表明成熟的 PrP 形式的半衰期为 3 至 6 小时。在感染痒病的神经母细胞瘤细胞与未感染的神经母细胞瘤细胞之间未观察到 PrP 生物合成存在差异。
Numerous studies have indicated that a modified proteinase K-resistant form of an endogenous brain protein, prion protein (PrP), is associated with scrapie infection in animals. This scrapie-associated PrP modification appears to occur posttranslationally in brain, but its molecular nature is not known. To learn about the normal PrP biosynthesis and whether it is altered by scrapie infection in vitro, we did metabolic labeling experiments with uninfected and scrapie-infected mouse neuroblastoma tissue culture cells. Pulse-chase labelling experiments indicated that, in both cell types, two major PrP precursors of 28 and 33 kilodaltons (kDa) were processed to mature 30- and 35- to 41-kDa forms. Endoglycosidase H, tunicamycin, and phospholipase treatments revealed that the 28- and 33-kDa precursors resulted from the addition of high-mannose glycans to a 25-kDa polypeptide containing a phosphatidylinositol moiety and that maturation of the precursors involved the conversion of the high-mannose glycans to hybrid or complex glycans. Treatments of the live cells with trypsin and phosphatidylinositol-specific phospholipase C indicated that the mature PrP forms had half-lives of 3 to 6 h. No differences in PrP biosynthesis were observed between the scrapie-infected versus uninfected neuroblastoma cells.