Takada S, Gotoh Y, Hayashi S, Yoshida M, Koike K
Department of Gene Research, Cancer Institute, Tokyo, Japan.
J Virol. 1990 Feb;64(2):822-8. doi: 10.1128/JVI.64.2.822-828.1990.
Cellular DNAs from human livers chronically infected with hepatitis B virus (HBV) were analyzed by Southern blot hybridization for the presence of integrated HBV DNA. In 15 of 16 chronically infected hepatic tissues, random HBV DNA integration was evident. By molecular cloning and structural analyses of 19 integrants from three chronically infected hepatic tissues, deletion of cellular flanking DNA in all cases and rearrangement of HBV DNA with inverted duplication or translocation of cellular flanking DNA at the virus-cell junction in some cases were noted. Thus, the rearrangement of HBV DNA or cellular flanking DNA is not a specific incident of hepatocellular carcinoma formation. Detailed analyses of various integrants bearing rearranged viral DNA failed to indicate any gross structural alteration in cellular DNA, except for a small deletion at the integration site, indicating that viral DNA rearrangement with inverted duplication possibly occurs before integration of HBV DNA. Based on nucleotide sequencing analyses of virus-virus junctions, a one- to three-nucleotide identity was found. A mechanism for this inverted duplication of HBV DNA is proposed in which illegitimate recombination between two complementary viral strands may take place by means of a nucleotide identity at the junction site in a weakly homologous region (patchy homology) on one side of adjoining viral sequences. For virus-cell junctions, the mechanism may be basically similar to that for virus-virus junctions.
采用Southern印迹杂交分析法，对慢性感染乙型肝炎病毒（HBV）的人肝脏细胞DNA进行分析，以检测整合型HBV DNA的存在情况。在16个慢性感染的肝组织样本中，有15个样本存在随机的HBV DNA整合现象。通过对来自三个慢性感染肝组织的19个整合体进行分子克隆和结构分析，发现所有病例中细胞侧翼DNA均有缺失，部分病例中HBV DNA发生重排，在病毒-细胞连接处出现细胞侧翼DNA的反向重复或易位。因此，HBV DNA或细胞侧翼DNA的重排并非肝细胞癌形成的特异性事件。对携带重排病毒DNA的各种整合体进行详细分析后发现，除整合位点有小的缺失外，细胞DNA未出现任何明显的结构改变，这表明HBV DNA反向重复的重排可能发生在HBV DNA整合之前。基于病毒-病毒连接处的核苷酸序列分析，发现有1至3个核苷酸的同源性。本文提出了一种HBV DNA反向重复的机制，即两条互补病毒链之间的非法重组可能通过相邻病毒序列一侧弱同源区域（局部同源性）连接处的核苷酸同源性发生。对于病毒-细胞连接处，其机制可能与病毒-病毒连接处基本相似。
