Arabidopsis E2F1 binds a sequence present in the promoter of S-phase-regulated gene AtCDC6 and is a member of a multigene family with differential activities
Arabidopsis E2F1 binds a sequence present in the promoter of S-phase-regulated gene AtCDC6 and is a member of a multigene family with differential activities
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DOI：
10.1023/a:1011848528377
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发表时间：
2001-01-01
影响因子：
5.1
通讯作者：
Murray, JAH
中科院分区：
文献类型：
--
作者：
de Jager, SM;Menges, M;Murray, JAH
哺乳动物 E2F 转录因子由 E2F 和 DP 亚基组成，与其负调节因子 Rb 相关蛋白一起控制细胞分裂相关基因的表达。哺乳动物中存在 6 个 E2F 和 2 个 DP，但小麦、烟草和胡萝卜中仅已知单个 E2F 基因。在这里，我们表明 E2F 是拟南芥中的一个多基因家族，并报道了三个 E2F 样克隆 AtE2F1-3 的分离，与小麦、烟草和胡萝卜 E2F 的同一性为 45-62%。序列分析表明，AtE2F1和AtE2F3与先前鉴定的植物E2F密切相关，而AtE2F2与人类E2F6和果蝇dE2F2相关，后者因缺乏转录激活潜力而异常。与此一致的是，我们发现 AtE2F1 和 AtE2F3 激活酵母细胞中的转录并结合植物 Rb 蛋白，但 AtE2F2 不能激活转录或结合 Rb。在几个细胞周期相关基因的启动子中鉴定出了共有 E2F 结合位点，包括 D 型细胞周期蛋白 CycD3 和复制起点蛋白 CDC6 的拟南芥同源物。在 G1 晚期诱导 CycD3 和 CDC6 表达之前，在重新进入细胞周期的部分同步拟南芥细胞中观察到 AtE2F1-3 的积累。 AtE2F1 复合物在体外与共有 E2F 序列和 AtCDC6 启动子结合。我们得出结论，拟南芥包含一个功能独特的 E2F 基因家族，最有可能参与 G1 到 S 期的进展。
Mammalian E2F transcription factors are composed of E2F and DP subunits, and with their negative regulators, Rb-related proteins, govern expression of cell-division-related genes. Six E2Fs and two DPs are present in mammals, but only single E2F genes are known from wheat, tobacco and carrot. Here we show that E2Fs are a multigene family in Arabidopsis, and report isolation of three E2F-like clones AtE2F1-3, with 45-62% identity to wheat, tobacco and carrot E2Fs. Sequence analysis reveals that AtE2F1 and AtE2F3 are closely related to previously identified plant E2Fs, whereas AtE2F2 is related to human E2F6 and Drosophila dE2F2 which are unusual in lacking transcriptional activation potential. Consistent with this, we show that AtE2F1 and AtE2F3 activate transcription in yeast cells and bind a plant Rb protein, but AtE2F2 cannot activate transcription or bind Rb. Consensus E2F-binding sites were identified in promoters of several cell cycle related genes, including the D-type cyclin CycD3 and the Arabidopsis homologue of the replication origin protein CDC6. Accumulation of AtE2F1-3 was observed in partially synchronised Arabidopsis cells re-entering the cell cycle, before induction of CycD3 and CDC6 expression in late G1. AtE2F1 complexes bound to consensus E2F sequences and to the AtCDC6 promoter in vitro. We conclude that Arabidopsis contains a family of functionally distinct E2F genes, most probably involved in the G1-to-S phase progression.