Interactions of the transcription factors MIBP1 and RFX1 with the EP element of the hepatitis B virus enhancer
Interactions of the transcription factors MIBP1 and RFX1 with the EP element of the hepatitis B virus enhancer
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DOI：
10.1128/jvi.70.9.6060-6066.1996
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发表时间：
1996-09-01
影响因子：
5.4
通讯作者：
Zajac-Kaye, M
中科院分区：
文献类型：
--
作者：
Blake, M;Niklinski, J;Zajac-Kaye, M
我们以前证明，MIBP 1和RFX 1多肽在体内结合形成一个复合物，结合到c-myc基因中的MIF-1元件和主要组织相容性复合物II类X盒识别序列。我们现在表明，EP元件，一个关键的调控序列内的肝炎B病毒增强子I，也与MIBP 1和RFX 1。使用多克隆抗血清直接针对任何一个利福昔肽纯化的MIBP 1或来自主要组织相容性复合体II类启动子结合蛋白RFX 1的肽，我们表明，MIBP 1和RFX 1都存在于DNA-蛋白质复合物在EP网站。此外，虽然EP元件可以与几个相邻的元件协同作用，以反式激活B型肝炎病毒的表达，我们证明，EP网站单独可以抑制猿猴病毒40启动子的转录在一个位置和方向独立的方式，这表明沉默器在肝癌细胞中的功能。
We previously demonstrated that MIBP1 and RFX1 polypeptides associate in vivo to form a complex that binds to the MIF-1 element in the c-myc gene and the major histocompatibility complex class II X-box recognition sequence. We now show that the EP element, a key regulatory sequence within hepatitis B virus enhancer I, also associates with MIBP1 and RFX1. Using polyclonal antisera directed against either oligonucleotide-purified MIBP1 or a peptide derived from the major histocompatibility complex class II promoter-binding protein RFX1, we showed that MIBP1 and RFX1 are both present in the DNA-protein complexes at the EP site. In addition, while the EP element can act cooperatively with several adjacent elements to transactivate hepatitis B virus expression, we demonstrated that the EP site alone can repress transcription of simian virus 40 promoter in a position- and orientation-independent manner, suggesting a silencer function in hepatocarcinoma cells.