Environmental Genomics Section, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences-National Institutes of Health, Research Triangle Park, NC 27709, USA.
Oxid Med Cell Longev. 2013;2013:120305. doi: 10.1155/2013/120305. Epub 2013 May 25.
Nuclear factor- (erythroid-derived 2) like 2 (NFE2L2, NRF2) is a key transcriptional activator of the antioxidant response pathway and is closely related to erythroid transcription factor NFE2. Under oxidative stress, NRF2 heterodimerizes with small Maf proteins and binds cis-acting enhancer sequences found near oxidative stress response genes. Using the dietary isothiocyanate sulforaphane (SFN) to activate NRF2, chromatin immunoprecipitation sequencing (ChIP-seq) identified several hundred novel NRF2-mediated targets beyond its role in oxidative stress. Activated NRF2 bound the antioxidant response element (ARE) in promoters of several known and novel target genes involved in iron homeostasis and heme metabolism, including known targets FTL and FTH1, as well as novel binding in the globin locus control region. Five novel NRF2 target genes were chosen for followup: AMBP, ABCB6, FECH, HRG-1 (SLC48A1), and TBXAS1. SFN-induced gene expression in erythroid K562 and lymphoid cells were compared for each target gene. NRF2 silencing showed reduced expression in lymphoid, lung, and hepatic cells. Furthermore, stable knockdown of NRF2 negative regulator KEAP1 in K562 cells resulted in increased NQO1, AMBP, and TBXAS1 expression. NFE2 binding sites in K562 cells revealed similar binding profiles as lymphoid NRF2 sites in all potential NRF2 candidates supporting a role for NRF2 in heme metabolism and erythropoiesis.
核因子-（红系衍生 2 样 2）（NFE2L2，NRF2）是抗氧化反应途径的关键转录激活因子，与红细胞转录因子 NFE2 密切相关。在氧化应激下，NRF2 与小 Maf 蛋白形成异二聚体，并与氧化应激反应基因附近的顺式作用增强子序列结合。使用膳食异硫氰酸酯萝卜硫素（SFN）激活 NRF2，染色质免疫沉淀测序（ChIP-seq）鉴定了数百个新的 NRF2 介导的靶标，超出了其在氧化应激中的作用。激活的 NRF2 结合了几个已知和新的靶基因（包括已知靶标 FTL 和 FTH1）的启动子中的抗氧化反应元件（ARE），这些基因参与铁稳态和血红素代谢，以及珠蛋白基因座控制区的新结合。选择了五个新的 NRF2 靶基因进行后续研究：AMBP、ABCB6、FECH、HRG-1（SLC48A1）和 TBXAS1。比较了每个靶基因在红细胞 K562 和淋巴样细胞中 SFN 诱导的基因表达。NRF2 沉默显示在淋巴样、肺和肝细胞中表达减少。此外，K562 细胞中 NRF2 负调节因子 KEAP1 的稳定敲低导致 NQO1、AMBP 和 TBXAS1 的表达增加。K562 细胞中的 NFE2 结合位点显示与所有潜在 NRF2 候选物的淋巴样 NRF2 位点相似的结合谱，支持 NRF2 在血红素代谢和红细胞生成中的作用。
