乙肝病毒基因上一个新的维甲素受体反应元件的发现

The Identification of A New Retinoid Responsive Element on HBV Gene

在对人乙肝病毒ADR - 1进行计算机序列检索时 ,发现在BamHI和HincII酶切位点内存在一保守的维甲素受体反应元件序列。用构建好的包含这一片段的乙肝病毒基因亚克隆 pBamHI -HincII -CAT2 与人维甲素A受体hRARα或人维甲素X受体hRXRα共转染人特异性肝癌细胞HepG2 ,通过相应配体ATRA或 9-cisRA的刺激 ,使细胞内氯霉素乙酰基转移酶活力较不加配体刺激的对照细胞明显增强。为了排除HepG2细胞染色体上整合的乙肝病毒的影响 ,将上述实验在人非特异性肝癌细胞Hela中重复 ,所得结果一致。进一步的体外蛋白阻滞分析 ,发现转染pBamHI -HincII -CAT2 及hRARα并加以ATRA刺激的Hela细胞核抽提物与含已知RARE的DNA结合最强。这一结合在有竟争结合物存在时条带消失。从而确证在该亚克隆上含有一新的维甲素受体反应元件。此元件序列极端保守 ,由重复序列 5’ -AGGTCT - 3’相隔 6个基构成。

The constructed subclone of HBV (ADR-1) gene p BamHI-HincII-CAT 2 was transfected into the two human hepatoblastoma cell lines Hep G2 and Hela, together with either human retonoid receptor A plasmid o r human retonoid receptor X plasmid and treated with corresponding ligand. The C AT activity of the cells is found to increase significantly after treatment. Fur ther gel retardation assay confirmed that there is a new retonoid acid responsiv e element in the fragment of HBV gene between the restruction enzyme digestion s ite between BamHI and HincII. This element is highly conserved, formed b y two direct repeat sequences 5'-AGGTGT-3' separated by 6 bases.