含不同长度前C序列的乙型肝炎病毒核心抗原基因在重组痘苗病毒中的表达

核酸序列分析表明,乙型肝炎(乙肝)病毒核心抗原基因(C基因)编码区内存在两个ATG。目前认为第二个ATG为乙肝病毒C抗原的起始密码子,两个ATG之间的序列称为前C序列,共87bp。Uy、Rutter、Roossinck及景新等的研究表明,含前C序列时,C基因在大肠杆菌中的表达是形成具有HBeAg活性的P25~e膜蛋白,在哺乳动物细胞中的表达则是形成分泌性的HBeAg;不含前C序列时,在大肠杆菌和哺乳动物细胞中均形成P21~e

STUDIES ON EXPRESSION OF HEPATITIS B VIRUS C GENE WITH DIFFERENT LENGTH OF PRE-CORE SEQUENCE BY RECOMBINANT VACCINIA VIRUSES

The chimeric plasmid pPC-5,P5-C26 were constructed by cloning individually the fragments of HBcAg gene with the entire pre-core sequence or with partial pre-core sequence ( 27bp before second ATG ) into the transfer vector pGJP-5 under the control of P7.5 promoter. The different C gene fragments were separately inserted into the region of vaccinia virus TK gene using homologous recombination technique in vivo. The TK-phenotype recombinant viruses, designated V-PC and V-C26 were assayed for the activities of HBeAg and HBcAg using ELISA method. Further studies indicated that the recombinant virus V-PC could secret only HBeAg into medium both in human TK--143 cells and chick embryo fibroblast cells and no HBcAg activity was found even in supernatants concentrated by 100 folds. Both HBeAg and HBcAg activities could be detected in cells lysates. The recombinant virus VMC-1 ( containing C gene with 12 bp before second ATG) and V-C26 could express both HBeAg and HBcAg activities in TK--143 cells, but not secreted into the medium. The above results implied that the entire pre-core sequence probably plays an important role in the secretion of HBeAg.