T1762A1764变异对乙型肝炎病毒C启动子活性影响

目的 乙型肝炎病毒Ｃ基因调节序列存在较多变异，为探讨在诸多变异中，Ｔ１７６２Ａ１７６４变异对Ｃ区启动子活性空间起何作用。方法 用克隆及ＰＣＲ产物直接测序，检测Ｔ１７６２Ａ１７６４变异；并将含调节序列的ＰＣＲ产物插入到氯霉素乙酰转移酶表达质粒中，转染ＨｅｐＧ２细胞并瞬时表达。结果 通过比较野生株及变异株在ＣＰ区序列及ＣＡＴ表达水平显示，Ｔ１７６２Ａ１７６４变异在使ＣＡＴ表达下调中起主要作用。结论Ｔ１

Effect of mutation (T1762A1764) on hepatitis B virus core promoter activity]

OBJECTIVE: With the knowledge that the substituted mutation of T1762A1764 in hepatitis B virus (HBV) core promoter (CP) region was the most common variation during chronic HBV infection, we proceed to study the role that the mutation T1762A1764 plays in effecting the core promoter. METHODS: Seven patients with fulminant hepatitis and one asymptomatic HBV carrier were investigated for screening T1762A1764 mutation by cloning and PCR products direct sequencing. PCR products containing HBV precore/core gene regulatory sequences were directly cloned into chloramphenicol acetyltransferase (CAT) expressing plasmid. CAT assay was done to compare CAT expressing level after transfecting into HepG2 cell line and transient expression. RESULTS: Results reveal that T1762A1764 mutation was the main factor that represses CAT expression in vitro. CONCLUSION: Among the several other variations within hepatitis B virus' core promoter region, T1762A1764 mutation has mainly affected the down-regulating activity of core promoter.