Oono Y, Chen Q G, Overvoorde P J, Köhler C, Theologis A
Plant Gene Expression Center, 800 Buchanan Street, Albany, California 94710, USA.
Plant Cell. 1998 Oct;10(10):1649-62. doi: 10.1105/tpc.10.10.1649.
An Arabidopsis transgenic line was constructed expressing beta-glucuronidase (GUS) via the auxin-responsive domains (AuxRDs) A and B (BA-GUS) of the PS-IAA4/5 gene in an indoleacetic acid (IAA)-dependent fashion. GUS expression was preferentially enhanced in the root elongation zone after treatment of young seedlings with 10(-7) M IAA. Expression of the BA-GUS gene in the axr1, axr4, and aux1 mutants required 10- to 100-fold higher auxin concentration than that in the wild-type background. GUS expression was nil in the axr 2 and axr 3 mutants. The transgene was used to isolate mutants exhibiting altered auxin-responsive gene expression (age). Two mutants, age1 and age2, were isolated and characterized. age1 showed enhanced sensitivity to IAA, with strong GUS expression localized in the root elongation zone in the presence of 10(-8) M IAA. In contrast, age2 exhibited ectopic GUS expression associated with the root vascular tissue, even in the absence of exogenous IAA. Morphological and molecular analyses indicated that the age1 and age2 alleles are involved in the regulation of gene expression in response to IAA.
构建了一个拟南芥转基因株系，其通过PS-IAA4/5基因的生长素响应结构域（AuxRDs）A和B（BA-GUS）以吲哚乙酸（IAA）依赖的方式表达β-葡萄糖醛酸酶（GUS）。用10⁻⁷ M IAA处理幼苗后，GUS表达在根伸长区优先增强。与野生型背景相比，BA-GUS基因在axr1、axr4和aux1突变体中的表达需要高10到100倍的生长素浓度。axr 2和axr 3突变体中GUS表达为零。该转基因用于分离生长素响应基因表达改变（age）的突变体。分离并鉴定了两个突变体age1和age2。age1对IAA表现出增强的敏感性，在存在10⁻⁸ M IAA的情况下，根伸长区有强烈的GUS表达。相反，即使在没有外源IAA的情况下，age2也表现出与根维管组织相关的异位GUS表达。形态学和分子分析表明，age1和age2等位基因参与了对IAA响应的基因表达调控。
