A glucocorticoid-inducible transcription system causes severe growth defects in Arabidopsis and induces defense-related genes
A glucocorticoid-inducible transcription system causes severe growth defects in Arabidopsis and induces defense-related genes
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DOI：
10.1046/j.1365-313x.1999.00575.x
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发表时间：
1999-10-01
期刊：
影响因子：
7.2
通讯作者：
Singh, KB
中科院分区：
文献类型：
--
作者：
Kang, HG;Fang, YW;Singh, KB
利用糖皮质激素诱导的转录系统控制拟南芥转录因子AtEBP的表达。许多转基因AtEBP株系在地塞米松(DEX)上生长时存在发育和生长缺陷。地塞米松是一种强合成糖皮质激素。然而，这些生长缺陷并不局限于AtEBP系，而是在使用相同系统产生的其他转基因系中观察到，包括空载体系。在大约25%的AtEBP或空载体转基因株系中，这些生长缺陷是严重的，在某些情况下会导致死亡。由于AtEBP与植物的防御反应有关，因此还检测了特定的防御相关基因的表达，包括一些病程相关(PR)基因的表达。植物防御素基因PDF1，2在DEX处理后的所有转基因株系中都被强烈诱导，包括没有显示任何可观察到的DEX诱导的生长缺陷的空载体系。PR-5在所有细胞系中的诱导程度都较小，而PR-1、PR-2和苯丙氨酸解氨酶3(PAL3)的表达没有明显变化。虽然AtEBP转基因和PDF1.2的诱导对DEX浓度的要求相似，但诱导动力学明显不同，AtEBP转基因在1h内诱导，而PDF1.5只在24~48h诱导。虽然生长缺陷和基因表达变化的分子机制仍未确定，但这些变化似乎是糖皮质激素诱导系统本身的结果，因此可能限制该系统在控制拟南芥基因表达方面的有效性。
A glucocorticoid-inducible transcription system was employed to control the expression of AtEBP, an Arabidopsis transcription factor. A number of the transgenic AtEBP lines had developmental and growth defects when grown on dexamethasone (DEX), a strong synthetic glucocorticoid. However, these growth defects were not confined to the AtEBP lines but were observed with other transgenic lines that were generated using the same system, including empty vector lines. In about 25% of the AtEBP or empty vector transgenic lines, these growth defects were severe and in some cases led to death. As AtEBP has been linked to the plant defense response, the expression of specific defense-related genes, including a number of pathogenesis-related (PR) genes was also examined. PDF1,2 a plant defensin gene, was strongly induced in all transgenic lines examined following treatment with DEX, including empty vector lines that did not show any observable DEX-induced growth defect. PR-5 was induced to a lesser extent in ail the lines, while the expression of PR-1, PR-2 and phenylalanine ammonia-lyase 3 (PAL3) did not change significantly. While the induction of the AtEBP transgene and PDF1.2 had similar DEX concentration requirements, the kinetics of induction differed significantly, with the AtEBP transgene being induced within 1h and PDF1.5 only being induced between 24 and 48h. Although the molecular mechanisms underlying the growth defects and changes in gene expression remain to be determined, these changes appear to result from the glucocorticoid-inducible system itself, and may therefore limit the usefulness of this system for controlling gene expression in Arabidopsis.