Nishi Hirotaka, Neta Gila, Nishi Katsura H, Akers Latania M, Rikiyama Toshiki, Proctor Kimberle N, Murphy Barbara A, Johnson Alfred C
Laboratory of Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4264, USA.
Int J Mol Med. 2003 Jan;11(1):49-55.
The epidermal growth factor receptor gene is highly regulated and responsive to extracellular stimuli that control cell growth. We have identified five putative nuclear factor-kappaB (NF-kappaB) binding sites within the epidermal growth factor receptor (EGFR) promoter region by sequence analysis. We have analyzed the potential role of NF-kappaB family members in the regulation of the EGFR transcription. Electrophoretic mobility shift analysis demonstrated that the p50 and p49, subunit proteins of the NF-kappaB, bound to the EGFR promoter at four out of five of these sites. However, it was found that NF-kappaB could not transactivate the EGFR by cotransfection experiments with each NF-kappaB subunit, using p50, p65 and c-Rel and an EGFR promoter luciferase reporter. Treatment of cells with tumor necrosis factor (TNF)-alpha, which could degrade the I-kappaB and then result in translocation of NF-kappaB to nucleus, did not enhance EGFR promoter reporter gene transcription. Also, TNF-alpha did not induce EGFR expression at the protein level. These results indicate that even though purified NF-kappaB can bind to the putative sites, there is no evidence that NF-kappaB transactivates the EGFR promoter region.
表皮生长因子受体基因受到高度调控，并对控制细胞生长的细胞外刺激作出反应。我们通过序列分析在表皮生长因子受体（EGFR）启动子区域内鉴定出五个假定的核因子-κB（NF-κB）结合位点。我们分析了NF-κB家族成员在EGFR转录调控中的潜在作用。电泳迁移率变动分析表明，NF-κB的p50和p49亚基蛋白与这些位点中的五个位点中的四个结合到EGFR启动子上。然而，通过使用p50、p65和c-Rel以及EGFR启动子荧光素酶报告基因与每个NF-κB亚基进行共转染实验发现，NF-κB不能激活EGFR。用肿瘤坏死因子（TNF）-α处理细胞，TNF-α可降解I-κB并导致NF-κB易位至细胞核，但这并未增强EGFR启动子报告基因的转录。此外，TNF-α在蛋白质水平上并未诱导EGFR表达。这些结果表明，尽管纯化的NF-κB可以结合到假定位点，但没有证据表明NF-κB能激活EGFR启动子区域。
