The Arabidopsis dwarf mutant shi exhibits reduced gibberellin responses conferred by overexpression of a new putative zinc finger protein
The Arabidopsis dwarf mutant shi exhibits reduced gibberellin responses conferred by overexpression of a new putative zinc finger protein
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DOI：
10.1105/tpc.11.6.1019
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发表时间：
1999-06-01
期刊：
影响因子：
11.6
通讯作者：
Sundberg, E
中科院分区：
文献类型：
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作者：
Fridborg, I;Kuusk, S;Sundberg, E
shi（短节间）是拟南芥中一种由转座子插入引起的半显性矮化突变，具有赤霉素（GA）生物合成缺陷突变体的典型表型。然而，GA的施用并没有纠正石属植物的矮化表型，这表明石属植物对GA的感知或反应存在缺陷。对shi基因的克隆发现，在shi中，转座子插入到未翻译的先导体中，从而使转座子上的花椰菜花叶病毒35S启动子向shi开放阅读框读出。这一结果与mRNA分析一起表明，shi突变体的表型是shi开放阅读框过表达的结果。预测的SHI氨基酸序列具有酸性和谷氨酰胺丰富的延伸，并且在假定的锌指区与三种推定的拟南芥蛋白显示序列相似性。这表明SHI可能通过转录控制作为GA应答的负调节因子。
shi (for short internodes), a semidominant dwarfing mutation of Arabidopsis caused by a transposon insertion, confers a phenotype typical of mutants defective in the biosynthesis of gibberellin (GA). However, the application of GA does not correct the dwarf phenotype of shi plants, suggesting that shi is defective in the perception of or in the response to GA. In agreement with this observation, the level of active GAs was elevated in shi plants, which is the result expected when feedback control of GA biosynthesis is reduced, Cloning of the SHI gene revealed that in shi, the transposon is inserted into the untranslated leader so that a cauliflower mosaic virus 35S promoter in the transposon reads out toward the SHI open reading frame. This result, together with mRNA analysis, suggests that the phenotype of the shi mutant is a result of overexpression of the SHI open reading frame. The predicted amino acid sequence of SHI has acidic and glutamine-rich stretches and shows sequence similarity over a putative zinc finger region to three presumptive Arabidopsis proteins. This suggests that SHI may act as a negative regulator of GA responses through transcriptional control.