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PrP高度敏感的小鼠模型，并在体内可视化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PrPsc。构建了小鼠N端与人PrPc主要ORF区的融合蛋白与荧光蛋白(FP)的融合蛋白。由于人PrPc的C末端序列缺失，转基因融合蛋白可能是分泌型的。获得了4株(EGFP-鼠/人嵌合PrP)和5株(EBFP-鼠/人嵌合PrP)转基因株。转基因小鼠在全身器官中均有表达，在脑中也有高表达。由于转基因的调控区来自小鼠基因组，因此转基因表达水平和基因产物的加工过程可能与内源性鼠普恩相似。不幸的是，由于PrPsc接种显示，在我们最新的合作研究中[Kitamoto(东北大学)、Mohri(九州大学)和Miyoshi，未发表的数据]中，携带编码秘书鼠/人嵌合PrP的转基因小鼠对人类PrP不敏感，该项目被搁置。我们以前的合作研究表明，表达人/鼠嵌合PrP的小鼠对人PrP高度敏感[Kitamoto(东北大学)、Mohri(九州大学)和Miyoshi，未发表的数据]，然而，将分子修饰为分泌型并不能有效地增强敏感性。

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for human prion in our latest collaborative study [Kitamoto (Tohoku University), Mohri (Kyushu University) and Miyoshi, unpublished data].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PrP was highly susceptible to human prion [Kitamoto (Tohoku University), Mohri (Kyushu University) and Miyoshi, unpublished data], however, modification of the molecule into secretary form was not effective to enhance the susceptibility.