Staiger D, Apel K, Trepp G
Institute for Plant Sciences, Swiss Federal Institute of Technology, ETH Center, Zurich.
Plant Mol Biol. 1999 Jul;40(5):873-82. doi: 10.1023/a:1006278030024.
In Arabidopsis thaliana, steady-state abundance of the Atger3 transcript encoding a germin-like cell wall protein follows a circadian rhythm, reaching its highest level at the beginning of the night. As a first step towards dissecting the molecular mechanisms underlying these transcript oscillations, the Atger3 genomic locus was characterised. Transcriptional fusions of 1.8 kb and 967 bp Atger3 promoter fragments to the beta-glucuronidase (GUS) reporter gene mediate high-amplitude circadian oscillations of the GUS transcript in transgenic Arabidopsis. 5' deletion to -490 greatly reduces overall transcript abundance while retaining a basal oscillation. Further deletion to -299 abolishes preferential GUS expression in the evening. Taken together, these data indicate that clock-response elements contributing to high-amplitude Atger3 oscillations largely reside between -299 and -967. Histochemical staining for GUS activity indicates that the Atger3 promoter is active in cotyledons, young leaves, petioles, the inflorescence axis, pedicels, sepals, ovary, style and siliques but not in roots, petals and anthers.
在拟南芥中，编码类萌发素细胞壁蛋白的Atger3转录本的稳态丰度呈现昼夜节律，在夜间开始时达到最高水平。作为剖析这些转录本振荡潜在分子机制的第一步，对Atger3基因组位点进行了表征。将1.8 kb和967 bp的Atger3启动子片段与β-葡萄糖醛酸酶（GUS）报告基因进行转录融合，介导转基因拟南芥中GUS转录本的高振幅昼夜振荡。5'端缺失至-490会大大降低总体转录本丰度，同时保留基础振荡。进一步缺失至-299会消除傍晚时GUS的优先表达。综合这些数据表明，促成Atger3高振幅振荡的生物钟响应元件主要位于-299至-967之间。GUS活性的组织化学染色表明，Atger3启动子在子叶、幼叶、叶柄、花序轴、花梗、萼片、子房、花柱和角果中具有活性，但在根、花瓣和花药中无活性。
