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Mol Plant:农科院作物所陈明课题组等揭示G蛋白β亚基调控植物下胚轴发育分子机制

摘要 : 2017年8月18日,国际著名学术杂志《Cell》子刊《Molecular Plant》杂志在线发表了中国农业科学院作物科学研究所作物转基因技术与应用创新团队陈明研究员和马有志研究员合作的一篇研究论文

2017年8月18日,国际著名学术杂志《Cell》子刊《Molecular Plant》杂志在线发表了中国农业科学院作物科学研究所作物转基因技术与应用创新团队陈明研究员和马有志研究员合作的一篇研究论文,研究报道了G 蛋白β亚基调控植物下胚轴发育的分子机制。研究论文题为“The G-protein β subunit AGB1 promotes hypocotyl elongation through inhibiting transcription activation function of BBX21 in Arabidopsis”。博士研究生徐东北为本文第一作者,转基因技术及应用创新团队的陈明研究员和马有志研究员为共同通讯作者。

G 蛋白复合体在植物逆境应答、生长及发育过程中发挥重要的调控作用。在拟南芥中,G蛋白复合体包含1个 Gα 亚基(GPA1),1个Gβ亚基(AGB1),和3个Gγ亚基,目前,对G 蛋白复合体各亚基功能的研究较多,但对G蛋白复合体如何调控下游信号途径仍然了解很少。植物种子萌发后的下胚轴发育对于植物幼苗完成出土,开始正常的光合作用以及完成生命周期至关重要。

研究以拟南芥G蛋白β亚基AGB1为诱饵,通过酵母双杂交筛选到一个直接与下胚轴延伸相关的B-box转录因子,BBX21。遗传分析显示AGB1与BBX21在下胚轴延伸中起相反的作用,并且BBX21位于AGB1的下游抑制下胚轴延伸。生化分析表明,BBX21蛋白的C端调节BBX21的核定位和转录激活特性,AGB1通过与BBX21的C端直接互作,抑制BBX21的转录激活和自激活功能,负调BBX21以及BBX21下游靶基因的表达,从而调控植物下胚轴的发育。该研究不仅解析了拟南芥中G蛋白β亚基调控植物下胚轴发育的分子机制,而且发现了G蛋白复合体调控下游信号途径的新方式,为进一步研究G蛋白相关的抗逆信号途径提供了线索。

原文链接:

The G-protein β subunit AGB1 promotes hypocotyl elongation through inhibiting transcription activation function of BBX21 in Arabidopsis

原文摘要:

Hypocotyl development in Arabidopsis thaliana is regulated by light and endogenous hormonal cues, making it an ideal model to study the interplay between light and endogenous growth regulators. BBX21, a B-box (BBX)-like zinc-finger transcription factor, integrates light and abscisic acid signals to regulate hypocotyl elongation inArabidopsis. Heterotrimeric G-proteins are pivotal regulators of plant development. The short hypocotyl phenotype of the G-protein β-subunit (AGB1) mutant (agb1-2) has been previously identified, but the precise role of AGB1 in hypocotyl elongation remains enigmatic. Here, we show that AGB1 directly interacts with BBX21, and the short hypocotyl phenotype of agb1-2 is partially suppressed in agb1-2bbx21-1 double mutant. BBX21 functions in the downstream of AGB1 and overexpression ofBBX21 in agb1-2 causes a more pronounced reduction in hypocotyl length, indicating that AGB1 plays an oppositional role in relation to BBX21 during hypocotyl development. Furthermore, we demonstrate that the C-terminal region of BBX21 is important for both its intracellular localization and its transcriptional activation activity that is inhibited by interaction with AGB1. ChIP assays showed that BBX21 specifically associates with its own promoter and with those of BBX22, HY5, and GA2ox1. which is not altered in agb1-2. These data suggest that the AGB1-BBX21 interaction only affects the transcriptional activation activity of BBX21 but has no effect on its DNA binding ability. Taken together, our data demonstrate that AGB1 positively promotes hypocotyl elongation through repressing BBX21 activity.

来源: Molecular Plant 浏览次数:0

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