A nuclear casein kinase 2 activity is involved in early events of transcriptional activation induced by salicylic acid in tobacco
A nuclear casein kinase 2 activity is involved in early events of transcriptional activation induced by salicylic acid in tobacco
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DOI：
10.1104/pp.125.1.396
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发表时间：
2001-01-01
期刊：
影响因子：
7.4
通讯作者：
Holuigue, L
中科院分区：
文献类型：
--
作者：
Hidalgo, P;Garretón, V;Holuigue, L
水杨酸(SA)激活基因的即刻早期转录，该基因由一组称为ns-L样元件的DNA启动子元件控制。这些元件在谷胱甘肽S转移酶基因的启动子中起作用。我们先前已经证明，SA在蛋白质磷酸化介导的过程中增加了烟草(Nictiana Tabacum Cv Xanthi NC)核因子与ns-1序列的结合。在这项研究中，我们给出了核蛋白激酶CK2(酪蛋白激酶2)参与了SA激活烟草的途径的证据。第一条证据来自对用SA或水作为对照的烟草植株核提取液中CK2活性的评估。这些实验结果表明，SA增加了细胞核CK2的活性。第二条证据来自5，6-二氯-L-(β-(D)-呋喃核糖)苯并咪唑(DRB)对AS-1序列对SA反应性的体内效应的评估。这些实验结果表明，在转基因烟草中，DRB削弱了SA对AS-1元件四聚体控制的GLIS报告基因和编码谷胱甘肽S转移酶的内源Gnt35基因转录的激活作用。DRB还削弱了SA对核因子与AS-1元件结合的增强作用。此外，被合成的生长素2，4-二氯苯氧乙酸和茉莉酸甲酯激活的AS-1/GUS报告基因的转录也被DRB抑制。据我们所知，这是第一个关于植物激素激活CK2酶的报道。
Salicylic acid (SA) activates immediate early transcription of genes controlled by a family of DNA promoter elements named ns-l-like elements. These elements are functional in the promoter of glutathione S-transferase genes. We have previously shown that SA increases the binding of tobacco (Nicotiana tabacum cv Xanthi nc) nuclear factors to the ns-1 sequence in a process mediated by protein phosphorylation. In this study we give evidence for the participation of a nuclear protein kinase CK2 (casein kinase 2) in the pathway activated by SA in tobacco. The first line of evidence comes from the evaluation of the CK2 activity in nuclear extracts prepared from tobacco plants treated with SA or water as a control. Results from these experiments indicate that SA increases the nuclear CK2 activity. The second line of evidence derives from the evaluation of the in vivo effect of 5,6-dichloro-l-(beta-(D)-ribofuranosyl) benzimidazole (DRB), a cell-permeable CK2 inhibitor, on the responsiveness of the as-1 sequence to SA. Results from these experiments indicate that DRB impairs the activating effect of SA on the transcription of both, the GLIS reporter gene controlled by a tetramer of the as-1 element, and the endogenous gnt35 gene encoding a glutathione S-transferase, in transgenic tobacco plants. DRB also impaired the increasing effect of SA on the binding of nuclear factors to the as-1 element. Furthermore, transcription of the as-1/GUS reporter gene activated by the synthetic auxin 2,4-dichlorophenoxyacetic acid and by methyl jasmonate was also inhibited by DRB. To our knowledge, this is the first report in which activation of a CK2 enzyme by a plant hormone is reported.