van der Zaal B J, Droog F N, Pieterse F J, Hooykaas P J
Institute of Molecular Plant Sciences, Leiden University, Clusius Laboratory, The Netherlands.
Plant Physiol. 1996 Jan;110(1):79-88. doi: 10.1104/pp.110.1.79.
We have investigated the cis-acting potential of several as elements (20-bp as-1/ocs-like sequences) in both yeast and plant cells. These TGACG[N7]TGACG-resembling elements were surprisingly similar with respect to their ability to confer inducibility by auxins and related compounds to a heterologous TATA box in stably transformed plant cells. Both in plant cells and in yeast it was found that differences between as elements were of a quantitative nature. A strong element based on the consensus sequence for as elements conferred the highest level of gene expression. The rather aberrant as elements present in the promoters of auxin-inducible gst genes Nt103 and Nt114 of tobacco were much weaker cis-acting elements. The ability of an element to drive reporter gene expression was found to correlate with the extent to which proteins present in (nuclear) extracts of yeast and plant cells bound to it. The cloned transcription factor TGA1a was shown to be a very good candidate to be the factor that mediates the in vivo regulation of gene expression via as elements. The physiological significance of gene activation by active and inactive auxins is discussed.
我们已经在酵母和植物细胞中研究了几种as元件(20个碱基对的as-1/ocs样序列)的顺式作用潜力。这些类似于TGACG[N7]TGACG的元件在赋予稳定转化的植物细胞中生长素和相关化合物对异源TATA盒诱导性的能力方面惊人地相似。在植物细胞和酵母中都发现,as元件之间的差异是定量性质的。基于as元件共有序列的强元件赋予了最高水平的基因表达。烟草生长素诱导型gst基因Nt103和Nt114启动子中存在的相当异常的as元件是较弱的顺式作用元件。发现一个元件驱动报告基因表达的能力与酵母和植物细胞(核)提取物中存在的蛋白质与之结合的程度相关。克隆的转录因子TGA1a被证明是通过as元件介导基因表达体内调控的因子的一个很好的候选者。讨论了活性和非活性生长素激活基因的生理意义。