The role of c-Jun phosphorylation in EpRE activation of phase II genes.
The role of c-Jun phosphorylation in EpRE activation of phase II genes.
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DOI：
10.1016/j.freeradbiomed.2009.07.036
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发表时间：
2009-10-15
影响因子：
7.4
通讯作者：
Forman, Henry Jay
中科院分区：
文献类型：
--
作者：
Levy, Smadar;Jaiswal, Anil K.;Forman, Henry Jay
关键词：
与EpRE元件结合的转录因子在II期基因的调控中起关键作用。在本研究中，我们检测了Nrf2与EpRE结合的伙伴c-Jun是否需要JNK的磷酸化才能结合和转录激活。我们使用染色质免疫沉淀法（ChIP）来测量nqo2、gclc和gclm中转录因子对EpRE序列的募集，western分析JNK的磷酸化，以及EpRE驱动的报告和JNK特异性抑制剂肽来确定c-Jun磷酸化的潜在重要性。将人支气管上皮细胞（HBE1）和人肝癌细胞（HepG2）暴露于4-羟基-2-壬烯醛（HNE）中，并检测相同EpRE序列的调节差异。我们发现，在HepG2细胞中，HNE暴露后c-Jun与EpRE序列的结合增加；然而，在暴露于hne的HBE1细胞中，只有磷酸化的c-Jun与三个EpRE序列的结合增加。尽管磷酸化的c-Jun结合增加，但EpREs报告者试验显示，抑制c-Jun磷酸化对HBE1细胞中基础和hne诱导的gclc和gclm转录有不同的影响。因此，就其在介导hne诱导epre介导的转录中的作用而言，c-Jun似乎是Nrf2的伴侣，尽管其磷酸化形式可能在一种细胞类型中占主导地位，但c-Jun磷酸化对转录的影响可能因基因而异。这与AP-1/TRE介导的转录激活中c-Jun磷酸化的既定要求形成明显对比。
The transcription factors that bind to EpRE elements play a key role in the regulation of phase II genes. In this study, we examined whether c-Jun, a partner of Nrf2 in binding to EpRE, requires phosphorylation by JNK for binding and transcriptional activation. We used chromatin immunoprecipitation assays (ChIP) to measure recruitment of transcription factors to EpRE sequences in nqo2, gclc and gclm, western analysis for phosphorylation of JNK, and EpRE driven reporters along with a JNK specific inhibitor peptide to determine the potential importance of c-Jun phosphorylation. Human bronchial epithelial (HBE1) and human hepatoma (HepG2) cells were exposed to 4-hydroxy-2-nonenal (HNE) and differences in regulation of the same EpRE sequences examined. We found binding of c-Jun to EpRE sequences increased subsequent to HNE exposure in HepG2 cells; however, in HNE-exposed HBE1 cells, binding of only phosphorylated c-Jun to the three EpRE sequences increased. Despite the increase in binding of phosphorylated c-Jun, reporter assays for EpREs showed that inhibition of c-Jun phosphorylation had variable effects on basal and HNE-induced transcription of gclc and gclm in HBE1 cells. Thus, in terms of its role in mediating HNE-induction of EpRE-mediated transcription, c-Jun appears to be a partner of Nrf2 and while its phosphorylated form may predominate in one cell type versus another, the effect of phosphorylation of c-Jun on transcription can vary with the gene. This contrasts markedly with the well-established requirement for phosphorylation of c-Jun in the activation of AP-1/TRE mediated transcription.
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影响因子：
4.1
作者：
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通讯作者：
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DOI：
10.1006/bbrc.1995.1493
发表时间：
1995-04-06
影响因子：
3.1
作者：
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通讯作者：
GIPP, JJ