The HAT2 gene, a member of the HD-Zip gene family, isolated as an auxin inducible gene by DNA microarray screening, affects auxin response in Arabidopsis
The HAT2 gene, a member of the HD-Zip gene family, isolated as an auxin inducible gene by DNA microarray screening, affects auxin response in Arabidopsis
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DOI：
10.1046/j.1365-313x.2002.01488.x
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发表时间：
2002-12-01
期刊：
影响因子：
7.2
通讯作者：
Koshiba, T
中科院分区：
文献类型：
--
作者：
Sawa, S;Ohgishi, M;Koshiba, T
植物激素，生长素，调节生长和发育的许多方面。尽管它的重要性，生长素的作用的分子机制基本上是未知的。为了获得更全面的了解生长素的主要反应，我们分析了基因的表达在拟南芥幼苗吲哚-3-乙酸（IAA）处理15分钟。我们确定了一个单一的基因，是下调早期，和29个基因，是上调早期。几种类型的典型转录因子被确定为早期上调基因，这表明生长素信号是由一组不同的转录调控因子介导的。在对生长素有反应的基因中，同源盒基因HAT 2的表达被迅速诱导。此外，我们表明，HAT 2的表达是由生长素诱导，而不是由其他植物激素。为了分析HAT 2在植物对生长素的反应中的功能，我们产生了35 S：：HAT 2转基因植物。这些产生长下胚轴，上位子叶，长叶柄，和小叶，这是生长素过量生产突变体，superroot 1（sur 1）和superroot 2（sur 2）的表型的特征。另一方面，与野生型植物相比，35 S：：HAT 2植物显示降低的侧根伸长和降低的生长素敏感性。结合RNA印迹和生化分析结果，这些发现表明HAT 2在芽和根组织中在调节生长素介导的形态建成中起相反的作用。
The plant hormone, auxin, regulates many aspects of growth and development. Despite its importance, the molecular mechanisms underlying the action of auxin are largely unknown. To gain a more comprehensive understanding of the primary responses to auxin, we analyzed the expression of genes in Arabidopsis seedlings treated with indole-3-acetic acid (IAA) for 15 min. We identified a single gene that is downregulated early, and 29 genes that are upregulated early. Several types of typical transcription factors are identified as early upregulated genes, suggesting that auxin signals are mediated by a master set of diverse transcriptional regulators. Of the genes that responded to auxin, the expression of the homeobox gene, HAT2 , was induced rapidly. Furthermore, we show that the expression of HAT2 is induced by auxin, but not by other phytohormones. To analyze the function of HAT2 in the plant's response to auxin, we generated 35S::HAT2 transgenic plants. These produced long hypocotyls, epinastic cotyledons, long petioles, and small leaves, which are characteristic of the phenotypes of the auxin-overproducing mutants, superroot1 (sur1) and superroot2 (sur2) . On the other hand, 35S::HAT2 plants showed reduced lateral root elongation, and reduced auxin sensitivity compared to wild-type plants. Together with the results of RNA blotting and biochemical analyses, these findings suggest that HAT2 plays opposite roles in the shoot and root tissues in regulating auxin-mediated morphogenesis.