Bogomolski-Yahalom V, Klein A, Greenblat I, Haviv Y, Tur-Kaspa R
Department of Medicine, Hadassah University Hospital, Jerusalem, Israel.
Virus Res. 1997 May;49(1):1-7. doi: 10.1016/s0168-1702(96)01429-3.
The surface antigen (S) gene promoter, one of the major hepatitis B virus (HBV) promoters, directs the synthesis of a 2.1 kb mRNA which encodes the preS2 and S polypeptides. The preS2/S promoter does not contain a classical TATA box, and transcription regulation of the preS2/S gene has not been fully elucidated. We analysed two regions involved in preS2/S gene transcription of the HBV adw subtype: the diverged TATA box and a putative initiator element. We demonstrated sequence specific promoter activity of the putative TATA-like sequences in the preS2/S gene promoter (-25 to -32 bp). Using end labeled synthetic oligonucleotides we observed specific binding of nuclear extracts to the diverged TATA sequence, that was significantly reduced using a mutated oligonucleotide. Specific binding of yeast TBP to the diverged TATA sequence was shown which was increased in the mutant containing a classical TATA box. We analysed the proposed initiator (Inr) sequence of the preS2/S promoter region (-13 to -16 bp). Deletion of the inr element markedly reduced promoter activity as assessed by CAT expression. Gel shift assays showed specific binding of nuclear extracts to wild type but not to mutant Inr. Expression studies with double mutants of the diverged TATA and the Inr element established that both elements are active in transcription regulation.
表面抗原（S）基因启动子是乙型肝炎病毒（HBV）的主要启动子之一，它指导合成一种2.1 kb的mRNA，该mRNA编码前S2和S多肽。前S2/S启动子不包含典型的TATA盒，前S2/S基因的转录调控尚未完全阐明。我们分析了HBV adw亚型前S2/S基因转录涉及的两个区域：分歧的TATA盒和一个假定的起始元件。我们证明了前S2/S基因启动子（-25至-32 bp）中假定的类TATA序列的序列特异性启动子活性。使用末端标记的合成寡核苷酸，我们观察到核提取物与分歧的TATA序列的特异性结合，使用突变的寡核苷酸时这种结合显著减少。显示酵母TBP与分歧的TATA序列特异性结合，在含有经典TATA盒的突变体中这种结合增加。我们分析了前S2/S启动子区域（-13至-16 bp）的假定起始子（Inr）序列。通过CAT表达评估，Inr元件的缺失显著降低了启动子活性。凝胶迁移试验显示核提取物与野生型而非突变型Inr特异性结合。对分歧的TATA和Inr元件双突变体的表达研究表明，这两个元件在转录调控中均有活性。
