Biochemical and functional properties of a palindromic sequence motif within the hepatitis B virus enhancer 1.
Biochemical and functional properties of a palindromic sequence motif within the hepatitis B virus enhancer 1.
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乙型肝炎病毒增强子 1 内回文序列基序的生化和功能特性。
DOI：
10.1006/viro.1999.9776
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Siddiqui,A
中科院分区：
文献类型：
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作者：
Kosovsky,MJ;Siddiqui,A
B型肝炎病毒（HBV）增强子1是一种转录元件，有助于HBV基因表达的肝脏特异性调节。我们以前确定了一个新的蛋白质结合位点的增强子，包含一个8 bp的回文序列基序。该基序与核因子1和肝细胞核因子3β（HNF 3 β）的结合位点部分重叠。此外，我们证明了这个新的位点被一种或多种蛋白质识别，暂时命名为回文结合因子（PBF），与HNF 3 β协同相互作用。在目前的工作中，我们进一步研究了PBF的生化和功能属性。蛋白质-DNA相互作用研究表明，位于回文序列基序3′-末端的三个胸苷残基对于最大PBF结合活性是重要的。当蛋白质-DNA复合物通过暴露于紫外线（UV）光进行光交联时，发现具有50 kDa的表观分子量的突出多肽与PBF结合位点相关联。此外，瞬时转染研究支持PBF通过涉及至少一个其他顺式作用序列基序（HNF 3 β结合位点）的组合机制促进增强子1活性的假设。
The hepatitis B virus (HBV) enhancer 1 is a transcriptional element that contributes to the liver-specific regulation of HBV gene expression. We previously identified a novel protein binding site within the enhancer that contains an 8-bp palindromic sequence motif. This motif partially overlaps the binding sites for nuclear factor 1 and hepatocyte nuclear factor 3β (HNF3β). Moreover, we demonstrated that this novel site is recognized by a protein or proteins, tentatively designated as palindrome-binding factor (PBF), that cooperatively interact with HNF3β. In the present work, we have further examined the biochemical and functional attributes of PBF. Protein–DNA interaction studies indicate that three thymidine residues located at the 3′-end of the palindromic sequence motif are important for maximal PBF-binding activity. When protein–DNA complexes were photocrosslinked by exposure to ultraviolet (UV) light, a prominent polypeptide with an apparent molecular mass of 50 kDa was found to associate with the PBF-binding site. Furthermore, transient transfection studies support the hypothesis that PBF contributes to enhancer 1 activity by a combinatorial mechanism that involves at least one other cis-acting sequence motif, the HNF3β-binding site.