Cirhin up-regulates a canonical NF-κB element through strong interaction with Cirip/HIVEP1
Cirhin up-regulates a canonical NF-κB element through strong interaction with Cirip/HIVEP1
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DOI：
10.1016/j.yexcr.2009.08.017
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发表时间：
2009-11-01
影响因子：
3.7
通讯作者：
Richter, Andrea
中科院分区：
文献类型：
--
作者：
Yu, Bin;Mitchell, Grant A.;Richter, Andrea
北美印第安儿童肝硬化（NAIC/CIRH 1A）是一种严重的常染色体隐性遗传性肝内胆汁淤积症。所有NAIC患者在CIRH 1A中都有一个纯合突变，该突变将Cirhin中保守的Arg 565改变为Trp（R565 W），Cirhin是一种功能未知的核仁蛋白。亚细胞定位不受突变的影响。酵母双杂交筛选鉴定了Cirip（Cirhin相互作用蛋白），发现Cirip与R565 W-Cirhin的相互作用减弱。从HeLa细胞核提取物的两种蛋白质的免疫共沉淀强烈支持酵母双杂交的结果。Cirip与HIVEP 1的C末端具有基本相同的序列，HIVEP 1是典型NF-κ B序列的调节因子。由于Cirip具有这种相互作用所需的锌指，我们开发了一种基于哺乳动物细胞中该元件的体外测定，以证明功能性Cirhin-Cirip相互作用。Cirip对NF-κ B序列的强正效应被Cirhin和R565 W-Cirhin进一步增加。重要的是，R565 W-Cirhin的作用弱于野生型蛋白。我们观察到在存在该NF-κ B序列的情况下，核提取物中Cirhin-Cirip复合物的水平增加。我们的假设是，Cirhin是该NF-κ B B序列的转录调节因子，并且可能参与调节具有NF-κ B B应答元件的其他基因。由于通过NF-κ B B反应元件调控的基因活动在发育过程中特别重要，这种相互作用可能是解释NAIC围产期出现的关键。(C)2009 Elsevier Inc. All rights reserved.
North American Indian childhood cirrhosis (NAIC/CIRH1A) is a severe autosomal recessive intrahepatic cholestasis. All NAIC patients have a homozygous mutation in CIRH1A that changes conserved Arg565 to Trp (R565W) in Cirhin, a nucleolar protein of unknown function. Subcellular localization is unaffected by the mutation. Yeast two-hybrid screening identified Cirip (Cirhin interaction protein) and found that interaction between Cirip and R565W-Cirhin was weakened. Co-immunoprecipitation of the two proteins from nuclear extracts of HeLa cells strongly supports the yeast two hybrid results. Cirip has essentially the same sequence as the C-terminal of HIVEP1, a regulator of a canonical NF-kappa B sequence. Since Cirip has the zinc fingers required for this interaction, we developed an in vitro assay based on this element in mammalian cells to demonstrate functional Cirhin-Cirip interaction. The strong positive effect of Cirip on the NF-kappa B sequence was further increased by both Cirhin and R565W-Cirhin. Importantly, the effect of R565W-Cirhin was weaker than that of the wild type protein. We observed increased levels of Cirhin-Cirip complex in nuclear extracts in the presence of this NF-kappa B sequence. Our hypothesis is that Cirhin is a transcriptional regulatory factor of this NF-kappa B sequence and could be a participant in the regulation of other genes with NF-kappa B responsive elements. Since the activities of genes regulated through NF-kappa B responsive elements are especially important during development, this interaction may be a key to explain the perinatal appearance of NAIC. (C) 2009 Elsevier Inc. All rights reserved.