目的检测肝脏X受体(Liver X receptor alpha,LXRα)在HBV阳性肝硬化组织及原发性肝癌中的表达情况及临床意义。方法收集20例揭阳市人民医院及汕头大学医学院第一附属医院手术切除的HBV阳性肝硬化原发性肝癌组织标本,应用免疫组化染色检测LXRα表达。Huh7细胞中分别过表达小鼠mLXRα,及共过表达HBx(HBV X protein)和mLXRα,并检测mLXRα及HBx对内源性LXRα信号通路下游靶基因SREBP-1(Sterol regulatory element-binding protein 1)的影响;双荧光素酶报告系统检测人肝癌Huh7细胞中HBx对LXRα转录活性的影响。结果 LXRα在肝硬化组织中阳性表达率为95%,高于癌组织的25%。HBx上调SREBP-1的表达可能与HBx调控LXRα的转录活性有关。结论 HBx通过调节癌前高表达的LXRα的转录活性,并影响其信号通路可能与HCC发生相关。
Tomato yellow leaf curl virus （TYLCV）, belonging to the genus Begomovirus of the family Geminiviridae, is emerging as the most destructive pathogen of tomato plants. Since the first report of TYLCV in Shanghai, China in 2006, TYLCV has spread rapidly to 13 provinces or autonomous regions of China. In this study, the molecular varia- bility and evolution of TYLCV were monitored in Shanghai from its first upsurge in 2006 until 2010. Full-length genomic sequences of 26 isolates were obtained by rolling circle amplification. Sequence analysis showed that the intergenic region was the most variable, with a mean mutation rate of 4.81×10-3 nucleotide substitutions per site per year. Ge- netic differentiation was found within isolates obtained from 2006, 2009, and 2010, though a linear increase in genetic diversity over time was not evident. Whilst significant parts of TYLCV genes were under negative selection, the C4 gene embedded entirely within the C1 gene had a tendency to undergo positive selection. Our results indicate that a mechanism of independent evolution of overlapping regions could apply to the natural population of TYLCV in Shanghai, China.
