Department of Biology, Pennsylvania State University, University Park, PA 16802, USA.
Mol Syst Biol. 2010 Jun 8;6:372. doi: 10.1038/msb.2010.28.
Heterotrimeric G-proteins mediate crucial and diverse signaling pathways in eukaryotes. Here, we generate and analyze microarray data from guard cells and leaves of G-protein subunit mutants of the model plant Arabidopsis thaliana, with or without treatment with the stress hormone, abscisic acid. Although G-protein control of the transcriptome has received little attention to date in any system, transcriptome analysis allows us to search for potentially uncommon yet significant signaling mechanisms. We describe the theoretical Boolean mechanisms of G-protein x hormone regulation, and then apply a pattern matching approach to associate gene expression profiles with Boolean models. We find that (1) classical mechanisms of G-protein signaling are well represented. Conversely, some theoretical regulatory modes of the G-protein are not supported; (2) a new mechanism of G-protein signaling is revealed, in which Gbeta regulates gene expression identically in the presence or absence of Galpha; (3) guard cells and leaves favor different G-protein modes in transcriptome regulation, supporting system specificity of G-protein signaling. Our method holds significant promise for analyzing analogous 'switch-like' signal transduction events in any organism.
三聚体 G 蛋白在真核生物中介导关键而多样的信号通路。在这里，我们生成并分析了模式植物拟南芥 G 蛋白亚基突变体的保卫细胞和叶片的微阵列数据，这些突变体或用应激激素脱落酸处理，或不用。尽管迄今为止，在任何系统中，G 蛋白对转录组的控制都没有受到太多关注，但转录组分析使我们能够搜索潜在的不常见但重要的信号机制。我们描述了 G 蛋白 x 激素调节的理论布尔机制，然后应用模式匹配方法将基因表达谱与布尔模型相关联。我们发现：(1)经典的 G 蛋白信号转导机制得到了很好的体现。相反，一些 G 蛋白的理论调控模式得不到支持；(2)揭示了一种新的 G 蛋白信号转导机制，其中 Gβ在 Galpha 存在或不存在的情况下以相同的方式调节基因表达；(3)保卫细胞和叶片在转录组调控中倾向于不同的 G 蛋白模式，支持 G 蛋白信号转导的系统特异性。我们的方法为分析任何生物体中类似的“开关式”信号转导事件提供了很大的前景。
