Over-expression of a truncated Arabidopsis thaliana heterotrimeric G protein γ subunit results in a phenotype similar to α and β subunit knockouts
Over-expression of a truncated Arabidopsis thaliana heterotrimeric G protein γ subunit results in a phenotype similar to α and β subunit knockouts
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DOI：
10.1016/j.gene.2007.02.008
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发表时间：
2007-05-15
期刊：
影响因子：
3.5
通讯作者：
Botella, Jose Ramon
中科院分区：
文献类型：
--
作者：
Chakravorty, David;Botella, Jose Ramon
异源三聚体G蛋白（Heterotrimeric G proteins，G-蛋白）是一类在植物中具有重要作用的信号转导蛋白。当G蛋白被激活时，它们解离成两个功能亚基（α和β γ，晚餐），有效地将信号传递给众多效应器。在动物系统中，β-γ二聚体通过γ亚基中存在的异戊二烯基锚定到质膜上，并且膜定位已被证明对于异源三聚体功能至关重要。设计了半显性负策略，旨在通过过表达缺少异戊二烯化基序（gamma*）的截短的y亚基来破坏拟南芥（生态型哥伦比亚）植物中的异源三聚体功能。北方分析表明，在几个转基因株系（35 S-γ *）中，突变体-γ亚基的表达水平比天然亚基高几个数量级。已经进行了35 S-γ * 系的深入表征，特别关注先前显示在α和β缺陷突变体中受影响的若干发育特征和对若干刺激的反应。在所有情况下，表达突变体γ亚基的转基因系以与α-和/或β-缺陷突变体相同的方式表现，尽管表型的严重性降低。我们的数据表明，信号从两个功能亚基，α和β/γ二聚体，在转基因植物中被破坏。尽管先前已经报道了亚基的物理关联，但我们的研究提供了拟南芥中α和β与γ亚基的功能关联的证据，同时也表明质膜定位可能对植物异源三聚体G蛋白的功能至关重要。(C)2007 Elsevier B. V.保留所有权利。
Heterotrimeric G proteins (G-proteins) are a diverse class of signal transducing proteins which have been implicated in a variety of important roles in plants. When G-proteins are activated, they dissociate into two functional subunits (a and the beta gamma, dinner) that effectively relay the signal to a multitude of effectors. In animal systems, the beta gamma dimer is anchored to the plasma membrane by a prenyl group present in the gamma subunit and membrane localization has proven vital for heterotrimer function. A semi-dominant negative strategy was designed aiming to disrupt heterotrimer function in Arabidopsis thaliana (ecotype Columbia) plants by over-expressing a truncated y subunit lacking the isoprenylation motif (gamma*). Northern analysis shows that the levels of expression of the mutant -y subunit in several transgenic lines (35S-gamma*) are orders of magnitude higher than that of the native subunits. In-depth characterization of the 35S-gamma* lines has been carried out, specifically focusing on a number of developmental characteristics and responses to several stimuli previously shown to be affected in alpha- and [beta-deficient mutants. In all cases, the transgenic lines expressing the mutant gamma subunit behave in the same way as the alpha- and/or the beta-deficient mutants, albeit with reduced severity of the phenotype. Our data indicates that signaling from both functional subunits, a and the beta/gamma dimer, is disrupted in the transgenic plants. Even though physical association of the subunits has been previously reported, our research provides evidence of the functional association of alpha and beta with the gamma subunits in Arabidopsis, while also suggesting that plasma membrane localization may be critical for function of plant heterotrimeric G proteins. (C) 2007 Elsevier B.V. All rights reserved.