Shen Q, Uknes S J, Ho T H
Department of Biology, Washington University, St. Louis, Missouri 63130.
J Biol Chem. 1993 Nov 5;268(31):23652-60.
The phytohormone, abscisic acid (ABA), plays a variety of roles during seed development and in the plant's response to environmental stresses. To study the molecular action of ABA, we have isolated a single copy ABA-induced gene, HVA22, which is mapped to barley chromosome 1. The HVA22 gene can be induced by either ABA or the protein synthesis inhibitor, cycloheximide, and addition of both inducers to barley aleurone layers has a synergistic effect on the expression of this gene. Sequence comparison indicates that the HVA22 gene product is highly homologous to the product of human DP1 gene, which is likely to contribute to colorectal tumorigenesis. The hormonal regulation of HVA22 expression has been studied, and there appear to be at least three elements, two located in the promoter and one in the first intron, which are essential for the high level of ABA induction of HVA22 expression. Among the promoter elements is a homolog of ABA response element, which has been shown to be important in the expression of other ABA-induced genes in plants. We suggest that the barley HVA22 gene product is likely a regulatory protein, and the ABA induction of this gene requires the action of a complex set of hormone response elements.
植物激素脱落酸（ABA）在种子发育过程以及植物对环境胁迫的响应中发挥着多种作用。为了研究ABA的分子作用，我们分离出了一个单拷贝的ABA诱导基因HVA22，该基因定位于大麦1号染色体上。HVA22基因可被ABA或蛋白质合成抑制剂环己酰亚胺诱导，将这两种诱导剂添加到大麦糊粉层对该基因的表达具有协同效应。序列比较表明，HVA22基因产物与人类DP1基因的产物高度同源，后者可能与结直肠癌的发生有关。对HVA22表达的激素调节进行了研究，似乎至少有三个元件，两个位于启动子中，一个位于第一个内含子中，它们对于HVA22表达的高水平ABA诱导至关重要。启动子元件中有一个ABA反应元件的同源物，已证明其在植物中其他ABA诱导基因的表达中很重要。我们认为大麦HVA22基因产物可能是一种调节蛋白，该基因的ABA诱导需要一组复杂的激素反应元件的作用。
