乙型肝炎病毒蛋白对纤维介素基因的激活作用

Hepatitis B Virus Proteins Promote Transcription of Fibroleukin Gene

纤维介素基因(fgl2)在人和小鼠的重型肝炎的发病机制中发挥重要作用.为探讨乙型肝炎病毒(HBV)编码蛋白对人纤维介素基因(hfgl2)的激活作用,构建了HBV编码蛋白C、S和X的真核表达质粒pcDNA-HBc、pcDNA-HBs和pcDNA-HBx,分别与hfgl2启动子荧光素酶报告基因质粒及β半乳糖苷酶基因质粒(-βGal)共转染到CHO细胞和HepG2细胞,采用免疫组织化学和免疫印记方法(Western blotting)鉴定病毒蛋白的表达.通过检测报告基因荧光素酶(LUC)及β半乳糖苷酶的表达活性,反映病毒蛋白对hfgl2启动子的转录激活作用.结果显示,转染了真核表达质粒的细胞均能瞬时表达相应的肝炎病毒蛋白,在CHO细胞,转染pcDNA-HBc组和pcDNA-HBx组相对荧光素酶的活性是对照组的5.4和6倍,在hepG2细胞,转染pcDNA-HBc组和pcDNA-HBx组相对荧光素酶的活性是对照组的8.7和11倍.研究表明,CHO和HepG2细胞中表达的HBV C蛋白和X蛋白均具有激活hfgl2的功能,而S蛋白则不能激活.进一步揭示了HBV病毒蛋白与宿主基因的相互作用机制.

Fibrinogen-like protein 2/ fibroleukin （fgl2） plays a pivotal role in the pathogenesis of both experimental and human fulminant viral hepatitis. The aim of this study was to investigate the key factor（s） of hepatitis B virus （HBV） that induces transcription of human fgl2 （hfgl2）. Three eukaryotic expression vectors（ pcDNA-HBc, pcDNA-HBs and pcDNA-HBx ）harboring HBV structure genes, C, S and X were constructed, individually. Chinese hamster ovary （CHO） ceils and HepG2 ceils were cotransfected with constructs expression HBV C, S and X proteins respectively, a hfgl2 promoter construct upstream of the luciferase report gene and a β-galactosidase （β-Gal） plasmid. Expression of these genes in eukaryotic ceils was detected by immunohistochemistry and Western blotting. The transcriptional activity of hfgl2 gene induced by three HBV proteins was determined by luciferase and β-galactosidase activity, respectively. The results showed that CHO ceils transfected with eukaryotic expression plasmids of HBV proteins could express HBV encoding proteins transiently. Relative luciferase activity in CHO cells transfected with pcDNA-HBc or pcDNA-HBx was an average of 5.4-fold and 6-fold increasing compared with the control group, and 8.7-fold and 11-fold in HepG 2 ceils. These results indicate that HBV C protein and X protein but not S protein activate the transcription of hfgl2 gene. It provides new insights in understanding the interaction between virus and host gene expression.