Establishment of model mouse susceptible to human prion; Visualization of the molecular interaction of prion protein in vivo

我们试图建立对人类朊病毒高度敏感的模型小鼠，并在体内可视化朊病毒蛋白（PrP）的分子相互作用，特别是通过转基因技术将正常细胞PrP转化为异常朊病毒（PrPsc）。该构建体设计用于编码由小鼠的n端序列和人PrPc的主要ORF区与荧光蛋白（FP）组成的嵌合蛋白的融合蛋白。由于从人PrPc中缺失了c端序列，因此从该转基因中获得的融合蛋白可能为秘书型。获得4个（egfp -鼠/人嵌合PrP）和5个（egfp -鼠/人嵌合PrP）转基因系。转基因小鼠在一般脏器中均有表达，且在脑组织中有高表达。由于该基因的调控区域来源于小鼠基因组，因此预计其表达水平和基因产物的加工过程与内源性小鼠朊病毒相似。不幸的是，该项目被暂停，因为在我们最新的合作研究中，接种PrPsc显示携带转基因编码秘书鼠/人嵌合PrP的转基因小鼠对人类朊病毒不敏感[Kitamoto (Tohoku University), Mohri （Kyushu University）和Miyoshi，未发表的数据]。我们之前的合作研究表明，表达鼠/人嵌合PrP的小鼠对人类朊病毒高度敏感[Kitamoto (Tohoku University), Mohri （Kyushu University）和Miyoshi，未发表的数据]，然而，将分子修饰为秘书形式并不能有效提高易感性。

We attempted to establish the model mice, which were highly susceptible for human prion and enabled the visualization of molecular interaction of prion protein (PrP) in vivo, especially conversion of normal cellular PrP into abnormal prion (PrPsc) by transgenic techniques. The constructs were designed to encode the fusion protein composed of chimeric protein which was composed of N-terminal sequences from mouse and main ORF region from human PrPc and Fluorescent protein (FP). As C-terminal sequences were deleted from human PrPc, the fusion protein derived from the transgene was expected to be secretary form. Four (EGFP-mouse/human chimeric PrP) and five (EBFP-mouse/human chimeric PrP) transgenic lines were produced. The transgenic mice showed expression of the transgene in the general organs, and high expression in the brain. Both the level of transgene expression and 1he processing of gene products was expected to be similar to that of endogenous mouse prion, as the regulatory region of the transgene were derived from mouse genome. Unfortunately, this project was suspended as inoculation of PrPsc revealed that the transgenic mice carrying the transgene encoding secretary mouse/human chimeric PrP were not susceptible for human prion in our latest collaborative study [Kitamoto (Tohoku University), Mohri (Kyushu University) and Miyoshi, unpublished data]. Our previous collaborative study indicated the mice expressing mouse/human chimeric PrP was highly susceptible to human prion [Kitamoto (Tohoku University), Mohri (Kyushu University) and Miyoshi, unpublished data], however, modification of the molecule into secretary form was not effective to enhance the susceptibility.