Wollersheim M, Debelka U, Hofschneider P H
Max-Planck-Institut für Biochemie, München, Federal Republic of Germany.
Oncogene. 1988 Nov;3(5):545-52.
Recently we have shown that the hepatitis B virus (HBV) X gene encodes a transactivating factor. Here we report on the construction of a series of HBx expression plasmids which were tested for a transactivating function by cotransfections with a plasmid expressing the CAT gene under control of the SV40 early promoter. One of the plasmids, expressing a HBx specific protein, is shown to transiently transactivate CAT gene expression after cotransfection into the human cell line CC113. Furthermore, a cloned integrated HBV DNA sequence is also shown to transactivate several viral promoters and LTRs. By sequence analyses we can demonstrate that only the HBx ORF is intact and that it is fused to an ORF of at least 228 bp in the flanking cellular DNA. The HBx gene is cotranscribed with the flanking cellular DNA, resulting in a RNA of approximately 10 kb. By subcloning of the integrate we can demonstrate that the presence of the HBx gene and its expression by the HBV enhancer and/or the HBx promoter is required for the transactivating function of the integrated HBV DNA.
最近我们发现乙肝病毒（HBV）X基因编码一种反式激活因子。在此我们报告一系列HBx表达质粒的构建，这些质粒通过与在SV40早期启动子控制下表达CAT基因的质粒共转染来检测其反式激活功能。其中一个表达HBx特异性蛋白的质粒，在共转染入人细胞系CC113后，显示能瞬时反式激活CAT基因表达。此外，一个克隆的整合HBV DNA序列也显示能反式激活多个病毒启动子和长末端重复序列（LTR）。通过序列分析我们可以证明只有HBx开放阅读框（ORF）是完整的，并且它与侧翼细胞DNA中至少228 bp的一个ORF融合。HBx基因与侧翼细胞DNA共转录，产生一个约10 kb的RNA。通过对整合体的亚克隆我们可以证明，整合的HBV DNA的反式激活功能需要HBx基因的存在及其由HBV增强子和/或HBx启动子的表达。
