在西安地区HBeAg阴性患者中检出乙型肝炎病毒前C区基因突变株

作用ＨＢｅＡｇ阴性，抗ＨＢｅ阳性患血清提取ＨＢＶ ＤＮＡ作为模板，用前Ｃ区引物进行聚合酶链反应（ＰＣＲ），选择３份ＰＣＲ扩增阳性产物，用ＥｃｏＲＩ酶切获得长为３１２ｂｐ的基因片段。将其克至ＰＵＣ１８质粒中，转化大肠杆菌ＪＭ１０９，提取质粒，经ＰＣＲ扩增及酶切鉴定后，用双脱氧末端标记法进行基因序列测定。结果发现，在２例患ＨＢＶ ＤＮＡ克隆中存在有前Ｃ区基因突变，即１８９６位的鸟嘌呤为腺嘌呤...

Detection of pre-C region mutants in hepatitis B virus from HBeAg-negative patients in Xi''''an area of China

HBV DNA extracted from the sera of HBeAg-negative and anti-HBe positive patients was amplified in polymerase chain reaction (PCR) with pre-C region primer. Positive products of PCR from 3 patients were chosen and digested with EcoR I. After purified from 1% low melting point agarose gel, we obtained the resulting fragment of 312 base pairs (bp) representing nt 1653 to 1964 and containing the pre-C region (nt 1814 to 1900); then they were cloned into plasmid PUC18 and transformated into E. coli JM109. Gene sequence was determined by didoxy chain termination method. The results showed that the gene mutation in 1896 site of HBV pre-C region was found in the clones of two patients. In that place, Guanine was replaced by Adenine. It, therefer, converted Trp-28 (TGG) into a stop codon (TAG) inhibiting the synthesis and secretion of HBeAg. This is the first report about the infection of mutants in HBV pre-C region detected in Xi'an area of China and it would play an important role in studying the pathogenesis of hepatitis B.