T_(1762)A_(1762)变异对乙型肝炎病毒C启动子活性影响

Effect of mutation (T_(I762)A_(1764)) on hepatitis B virus core promoter activity

国的乙型肝炎病毒（ＨＢＶ）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（ＣＰ）活性究竟起何作用。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（ＣＡＴ）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Ｔ１７６２Ａ１７６４变异在使ＣＰ活性下调中起主要作用。

Objective With the knowledge that the substituted mutation of T1762A1764 in hepatitis Bvirus (HBV) core promoter (CP) region was the most common variation during chronic HBV infection, weproceed to study the role that the mutation T1762A17bo plays in effecting the core promoter. MethodsSeven patients with fulminant hepatitis and one asymptomatic HBV carrier were investigated for screeningTi1762A1764 mutation by cloning and PCR products direct sequencing. PCR products containing HBVprecore/core gene regulatory sequences were directly cloned into chloramphenicol acetyltransferase (CAT)expressing plasmid. CAT assay was done to compare CAT expressing level after trans feeting into HepG2cell line and transient expression. Results Results reveal that T1762A1764 mutation was the main factorthat represses CAT expression in vitro. Conclusion Among the several other variations within hepatitis Bvirus core promoter region, T1762A1764 mutation has mainly affected tile down-regulating activity of corepromoter.