E2Ls, E2F-like Repressors of Arabidopsis that bind to E2F sites in a monomeric form
E2Ls, E2F-like Repressors of Arabidopsis that bind to E2F sites in a monomeric form
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DOI：
10.1074/jbc.m200913200
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发表时间：
2002-05-10
影响因子：
4.8
通讯作者：
Ohashi, Y
中科院分区：
文献类型：
--
作者：
Kosugi, S;Ohashi, Y
E2 F转录因子是细胞增殖的主要调节因子，并且每个因子对细胞周期控制的贡献不同。拟南芥含有6个E2 F同源物，其中3个是表现出与动物E2 F的总体相似性并与DPa和DPb相互作用以刺激DNA结合的蛋白质。在这里，我们描述了其他三个E2 F样蛋白从拟南芥，E2 L1 -3，其中有两个副本的一个域与一个有限的相似性，只有DNA结合域的E2 F。与已知的E2 F不同，这三种E2 L蛋白不能与DPa和DPb相互作用，并且可以通过双型结构域以单体形式有效地结合E2 F位点。转染实验表明，E2 Ls抑制E2 F调控的启动子控制下的报告基因的转录，表明E2 Ls的功能拮抗E2 F-DP介导的反式激活。当与绿色荧光蛋白融合时，E2 L1和E2 L3主要定位于细胞核，而E2 L2在细胞核和细胞质中都检测到。由于E2 Ls的转录本在分生组织中含量丰富，而在完全分化的组织中含量较少，因此E2 Ls可能与E2 F-DP的活性相平衡，从而抑制细胞增殖。
E2F transcription factors are major regulators of cell proliferation, and each factor contributes differently to cell cycle control. Arabidopsis contains six E2F homologs, of which three are proteins that exhibit an overall similarity to animal E2Fs and interact with DPa and DPb to stimulate DNA binding. Here we describe the other three E2F-like proteins from Arabidopsis, E2L1-3, which have two copies of a domain with a limited similarity only to the DNA binding domain of E2F. Unlike known E2Fs, the three E2L proteins failed to interact with DPa and DPb and could efficiently bind E2F sites in a monomeric form through the dual-type domain. Transfection assays revealed that E2Ls repress the transcription of reporter genes under the control of E2F-regulated promoters, indicating that E2Ls function to antagonize transactivation mediated by E2F-DP. When fused to green fluorescence protein, E2L1 and E2L3 were predominantly localized to the nucleus whereas E2L2 was detected in both the nucleus and cytoplasm. Because the transcripts of E2Ls were abundant in meristematic rather than fully differentiated tissues, E2Ls may balance the activities of E2F-DP and play a role in restraining cell proliferation.