Chang L Y, Yang W Y, Roth D
Department of Molecular Biology, University of Wyoming, Laramie, Wyoming, 82071-3944, USA.
Biochem Biophys Res Commun. 2000 Dec 20;279(2):468-74. doi: 10.1006/bbrc.2000.3964.
Translational control by specific eIF2alpha phosphorylation on serine 51 has been characterized in all eukaryotes with the significant exception of plants. In order to evaluate the capability of plant eIF2alpha to functionally control translation, the wild type (51S) and a nonphosphorylatable mutant (51A) of wheat eIF2alpha were expressed in a yeast genetic system. Expression of either wheat protein did not handicap growth under conditions that repress the eIF2alpha phosphorylation pathway. However, under conditions that induce specific eIF2alpha phosphorylation only strains expressing wheat 51S were able to grow between 2 and 4 days. Growth was dependent upon activity of yeast eIF2alpha kinase GCN2 and resulted in the increased translation of GCN4. The association between plant eIF2alpha and yeast eIF2B is supported by their specific coimmunoprecipitation from transgenic yeast cells. These data support the similarity among eukaryotic translational initiation processes and strengthen the concept that plants may contain an eIF2alpha phosphorylation pathway.
除了植物外，在所有真核生物中，丝氨酸51位点上特定的真核起始因子2α（eIF2α）磷酸化对翻译的调控作用都已得到表征。为了评估植物eIF2α在功能上控制翻译的能力，在酵母遗传系统中表达了小麦eIF2α的野生型（51S）和不可磷酸化突变体（51A）。在抑制eIF2α磷酸化途径的条件下，两种小麦蛋白的表达均未对生长造成阻碍。然而，在诱导特定eIF2α磷酸化的条件下，只有表达小麦51S的菌株能够在2至4天内生长。生长依赖于酵母eIF2α激酶GCN2的活性，并导致GCN4的翻译增加。植物eIF2α与酵母eIF2B之间的关联通过它们从转基因酵母细胞中的特异性共免疫沉淀得到证实。这些数据支持了真核生物翻译起始过程之间的相似性，并强化了植物可能含有eIF2α磷酸化途径的概念。
