Different behavior toward bovine spongiform encephalopathy infection of bovine prion protein transgenic mice with one extra repeat octapeptide insert mutation
Different behavior toward bovine spongiform encephalopathy infection of bovine prion protein transgenic mice with one extra repeat octapeptide insert mutation
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DOI：
10.1523/jneurosci.3811-03.2004
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发表时间：
2004-03-03
影响因子：
5.3
通讯作者：
Torres, JM
中科院分区：
文献类型：
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作者：
Castilla, J;Gutiérrez-Adán, A;Torres, JM
在人类中，Prion蛋白基因(PRNP)重复八肽区域的插入突变经常与家族性海绵状脑病有关。在这项研究中，表达牛PrP的转基因小鼠(boTg小鼠)携带额外的八肽插入到野生型(7个而不是6个)中，表现出牛海绵状脑病(BSE)感染过程的改变，反映为与表达类似水平的野生型六个八肽蛋白的boTg小鼠相比，孵育时间缩短。在两个boTg小鼠品系(bo60RTg和bo70RTg)中，孵化时间受到转基因表达水平和所使用的接种物的极大影响。针对BSE感染缺乏种间屏障的情况，我们通过组织病理学分析检测到典型的CNS海绵状变性征象，并通过Western印迹或免疫组织化学分析检测到牛PrPres的存在。当7or-PrPres在bo70rtg小鼠体内繁殖时，与bo60rtg小鼠相比，观察到类似的更早的临床体征。含有7个八肽(7or-PrPC和7or-PrPres)的蛋白质PrPC和PrPres对同源的6or-PrPC和6or-PrPres在非变性洗涤剂中表现出相似的蛋白酶敏感性和不溶性。此外，在常规生化技术诊断为阴性的标本中，bo70rtg小鼠比bo60rtg小鼠表现出更高的敏感性。在无临床症状的情况下，免疫组织化学和免疫印迹分析最早可在接种后120d检测到7or-PrPres。这些发现可能有助于我们改进目前的小鼠生物测定，并了解八肽重复区域在疾病易感性中的作用。
In humans, insert mutations within the repetitive octapeptide region of the prion protein gene (Prnp) are often associated with familial spongiform encephalopathies. In this study, transgenic mice expressing bovine PrP (boTg mice) bearing an additional octapeptide insertion to the wild type (seven octapeptide repeats instead of six) showed an altered course of bovine spongiform encephalopathy (BSE) infection, reflected as reduced incubation times when compared with boTg mice expressing similar levels of the wild-type six-octapeptide protein. In both boTg mouse lines (bo6ORTg and bo7ORTg), incubation times were affected drastically depending on transgene expression levels and the inoculum used. In accordance with the lack of an interspecies barrier to BSE infection, we detected the typical signs of CNS spongiform degeneration by histopathological analysis and the presence of the bovine prion PrPres by Western blot or immunohistochemical analyses. When 7OR-PrPres was propagated in bo7ORTg mice, a similar earlier onset of clinical signs was observed compared with bo6ORTg mice. Proteins PrPC and PrPres containing seven octapeptides (7OR-PrPC and 7OR-PrPres) showed similar protease sensitivity and insolubility in nondenaturing detergents to homologous 6OR-PrPC and 6OR-PrPres. In addition, bo7ORTg mice showed a higher sensitivity than bo6ORTg mice for detecting prion infection in specimens previously diagnosed as negative by conventional biochemical techniques. In the absence of clinical signs of disease, 7OR-PrPres could be detected as early as 120 d after inoculation by immunohistochemical and Western blot analyses. These findings may help us improve the current mouse bioassays and understand the role of the octapeptide repeat region in susceptibility to disease.