中文摘要：

目的：观察乙型肝炎病毒x蛋白（HBx）截短突变体在细胞内的定位及其对Wnt／βcatenin信号通路转录活性的影响。方法：采用PCR克隆全长野生型HBx基因，在此基础上，分别构建融合增强型绿色荧光蛋白（EGFP）基因和缺失HBx基因C端49-154aft,、C端85-154aa、N端1-57aa＋C端141～154aa、N端1-57aa或N端1-84aa截短突变体的表达载体；激光共聚焦显微镜下观察HBx截短突变体在HEK293细胞中的定位；采用萤光素酶报告系统检测HBx截短突变体对Wnt／[3-catenin信号通路转录活性的影响。结果：（1）成功构建了HBx截短突变体与EGFP基因融合的表达载体。（2）野生型HBx及截短突变体在HEK293细胞中具有不同的定位，其中N端缺失突变体主要定位于细胞核周胞质；c端缺失突变体在胞质胞核中呈均匀分布；N端＋C端缺失突变体的定位类似于野生型HBx，主要定位于胞质，呈不均一的粗大颗粒，胞核中也有少量表达。（3）与野生型HBx相比，HBxc端49～154aa、C端85-154Off,、N端1-57aa＋c端141～154aa、N端1-57aa和N端1-84aa缺失突变体在Huh7细胞中均使Wnt／β-catenin信号通路的转录活性明显下降，分别下降了78．7％、84．7％、75．7％、93．8％和95,5％。结论：HBx不同截短突变体的细胞定位及对Wnt／β-catenin信号通路转录活性不同，提示HBx的不同功能区对Wnt信号的转录激活发挥着不同的作用。

英文摘要：

AIM： To observe the intracellular location of hepatitis B virus X protein （HBx） truncated mutants and their impacts on the transcriptional activity of 13-catenin/T-cell factor 4 （TCF4） in Wnt signaling pathway. METHODS： The full length of wild-type HBx gene was cloned by PCR. The C-terminal of 49-154 aa （HBxI ）, C-termi- nal of 85 - 154 aa （ HBx2 ）, N-terminal of 1 - 57 aa and C-terminal 141 - 154 aa （ HBx3 ）, N-terminal of 1 - 57 aa （ HBx4 ）, and N-terminal of 1 - 84 aa （ HBx5 ） deletion mutants of HBx gene fused with enhanced green fluorescent protein （EGFP） gene （fl-IBxl, fHBx2, fHBx3, fHBx4 and fHBxs, respectively） were constructed. The intracellnlar locations of HBx truncated mutations were observed under confocal laser scanning microscope. Moreover, the effects of HBx truncated mutants on 13-eatenin/TGF4 transcriptional activity in Wnt signaling pathway were detected by luciferase reporter system. RESULTS ： The expression vectors of HBx truncated mutants fused with EGFP gene were successfully constructed. Expres- sion of wild-type HBx and its truncated mutants in HEK293 cells had distinct dual intracellular localizations. N-terminal deletion mutants localized mainly in perinuclear cytoplasm of transfected HEK293 cells. C-terminal deletion mutants were distributed evenly both in the nucleus and cytoplasm. Similar to the cellular localization of wild-type HBx, N-terminal and C-terminal deletion mutant localized mainly in the cytoplasm in a manner of heterogeneous coarse particles, and was alsoexpressed a little in the nucleus. Compared with wild-type HBx, either N-terminal or C-terminal truncated HBx mutants in- hibited 13-catenin/TCF4 transcriptional activity, with the inhibitory rate of 78.7% （fHBxI ）, 84.7% （fI-IBx2 ）, 75.7% （fHBx3 ）, 93.8% （fHBx4 ） and 95.5% （fHBx5 ）, respectively. CONCLUSION： HBx truncated mutants show discre- pant intracellular locations and different impacts on ~-catenin/TCF transcriptional activity in Wnt signaling pathwa