乙型肝炎病毒毒株X基因/C基因启动子的热点变异

目的ＨＢＶ／Ｘ基因存在调控ＨＢＶ复制的调节序列,Ｘ基因变异将影响这些调节序列功能,研究中国ＨＢＶ毒株Ｘ基因／Ｃ基因启动子（ＢＣＰ）区的变异情况。方法设计ＢＣＰ下游反义链错配引物,将点突变附近的一个碱基（ｎｔ１７６７）由Ａ→Ｔ,则正好可在ＢＣＰ变异株中引进一个ＢｃｌＩ（Ｔ↓ＧＡＴＣＡ）酶切位点,结合限制性片段长度多态性分析（ＲＦＬＰ）筛检１４３例中国人感染的ＨＢＶ毒株ＢＣＰ区变异,并与前Ｃ区变异比较。结果１１４例血清ＨＢＶＤＮＡ阳性慢性ＨＢＶ感染者,ＢＣＰ区和／或前Ｃ区变异者４９例（４３％）,ＢＣＰ变异者３７例（３２％）。ＢＣＰ变异无论在ＨＢｅＡｇ阳性或阴性慢性肝炎病例的发生率均显著高于慢性ＨＢＶ无症状感染者。ＢＣＰ可与前Ｃ终码变异共存或单独出现。结论在中国ＨＢＶ毒株ＢＣＰ区存在热点变异。ＨＢＶ毒株ＢＣＰ变异可能影响ＨＢＶ前Ｃ基因组ｍＲＮＡ转录,是ＨＢＶ感染持续和肝病变进展的原因之一。

Mismatched PCR combined with restriction fragment length polymorphism assay for identification of hot spot for mutation in core promoter sequence of hepatitis B virus in Chinese isolates

Objectives To investigate the prevalence of the core promoter variant in Chinese HBV carriers and to explore the clinical and epidemiological problems of the variant. Methods A novel method for detecting the double mutation in core promoter was developed. By using an antisense primer that starts at nt 1765 and bears a mismatch at nt 1767, we introduced an artificially created Bcl I cleavage site if the double mutation was present. The prevalence and clinical significance of mutation in the core promoter were investigated in 114 Chinese individuals infected with HBV. Results Serum samples from 37 asymptomatic carriers and patients harbored core promoter mutant, some with precore mutation. The prevalence was higher in carriers and patients without HBeAg than those with HBeAg. The results in the PCR RFLP assay perfectly agreed with the data from direct sequencing. Conclusion The presumed core promoter mutations resulting in decreased HBeAg synthesis might be one of the factors leading to persistence of HBV infection and active liver disease.