Wasylyk C, Bradford A P, Gutierrez-Hartmann A, Wasylyk B
Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, ULP, Illkirch, France.
Oncogene. 1997 Feb 27;14(8):899-913. doi: 10.1038/sj.onc.1200914.
Cell transformation by the Ras oncogene is mediated by members of the ets gene family. To analyse the mechanisms of regulation, we have studied activation of several ets factors by Ras expression. We show that expression of Ha-Ras strongly activates the Ets1 p68 and p54 isoforms and Ets2 in F9 EC cells. We have mapped the Ras responsive elements of Ets1 p68 to two domains, RI+II and RIII. Mutation of threonine 82 to alanine in RI+II abolishes both Ras activation and phosphorylation by MAP kinase. Threonine 82 is part of a sequence that is conserved in Drosophila Pointed P2, an ets protein that has been shown both genetically and biochemically to mediate Ras signalling in Drosophila cells. We extend the comparison of these evolutionary related proteins by showing that Pointed P2 is activated by Ras in mammalian cells and mutation of the homologous threonine abolishes activation. Furthermore, we show that Pointed P2 resembles Ets1, in that it has conserved sequences in a similar position adjacent to the ets DNA binding domain that negatively auto-regulates DNA binding. These results go towards showing that the Drosophila Pointed and vertebrate Ets1 are evolutionary related proteins that have remarkably conserved Ras regulatory mechanisms downstream from MAP kinase.
Ras癌基因介导的细胞转化是由ets基因家族的成员介导的。为了分析调控机制，我们研究了Ras表达对几种ets因子的激活作用。我们发现，Ha-Ras的表达在F9胚胎癌细胞中强烈激活Ets1 p68和p54亚型以及Ets2。我们已将Ets1 p68的Ras反应元件定位到两个结构域，RI+II和RIII。RI+II中苏氨酸82突变为丙氨酸会消除Ras激活和MAP激酶的磷酸化作用。苏氨酸82是果蝇Pointed P2中保守序列的一部分，Pointed P2是一种ets蛋白，已在遗传学和生物化学上证明其在果蝇细胞中介导Ras信号传导。我们通过证明Pointed P2在哺乳动物细胞中被Ras激活以及同源苏氨酸的突变消除激活作用，扩展了这些进化相关蛋白的比较。此外，我们表明Pointed P2与Ets1相似，因为它在与ets DNA结合结构域相邻的相似位置具有保守序列，该序列对DNA结合具有负向自调节作用。这些结果表明，果蝇的Pointed和脊椎动物的Ets1是进化相关的蛋白，它们在MAP激酶下游具有显著保守的Ras调控机制。
