Albani D, Mariconti L, Ricagno S, Pitto L, Moroni C, Helin K, Cella R
Department of Botany and Plant Ecology, University of Sassari, Via Muroni 25, 07100 Sassari.
J Biol Chem. 2000 Jun 23;275(25):19258-67. doi: 10.1074/jbc.M909390199.
In animal cells the progression of the cell cycle through G(1)/S transition and S phase is under the control of the pRB/E2F regulatory pathway. The E2F transcription factors are key activators of genes coding for several regulatory proteins and for enzymes involved in nucleotide and DNA synthesis. In this report we have detected the presence of E2F-like DNA binding activities in carrot nuclear extracts, and we have isolated a carrot cDNA (DcE2F) encoding a plant E2F homologue. The DcE2F gene is expressed in proliferating cells and is induced during the G(1)/S transition of the cell cycle. Supershift experiments using anti-DcE2F antiserum have confirmed that the DcE2F protein is a component of the carrot E2F-like nuclear activities. DNA binding assays have demonstrated that the DcE2F protein can recognize a canonical E2F cis-element in association with a mammalian DP protein. Furthermore, transactivation assays have revealed that DcE2F is a functional transcription factor that can transactivate, together with a DP partner, an E2F-responsive reporter gene in both plant and mammalian cells.
在动物细胞中，细胞周期从G(1)/S转换期到S期的进程受pRB/E2F调控途径的控制。E2F转录因子是多种调控蛋白以及参与核苷酸和DNA合成的酶的编码基因的关键激活因子。在本报告中，我们在胡萝卜核提取物中检测到了类似E2F的DNA结合活性，并且分离出了一个编码植物E2F同源物的胡萝卜cDNA（DcE2F）。DcE2F基因在增殖细胞中表达，并在细胞周期的G(1)/S转换期被诱导。使用抗DcE2F抗血清进行的超迁移实验证实，DcE2F蛋白是胡萝卜中类似E2F的核活性的一个组成部分。DNA结合分析表明，DcE2F蛋白可与哺乳动物DP蛋白结合，识别典型的E2F顺式元件。此外，反式激活分析表明，DcE2F是一种功能性转录因子，它能与DP伴侣一起在植物和哺乳动物细胞中反式激活E2F反应性报告基因。
