Goossens A, Dillen W, De Clercq J, Van Montagu M, Angenon G
Laboratorium voor Genetica, Departement Plantengenetica, Vlaams Interuniversitair Instituut voor Biotechnologie, Universiteit Gent, B-9000 Gent, Belgium.
Plant Physiol. 1999 Aug;120(4):1095-104. doi: 10.1104/pp.120.4.1095.
The regulatory sequences of many genes encoding seed storage proteins have been used to drive seed-specific expression of a variety of proteins in transgenic plants. Because the levels at which these transgene-derived proteins accumulate are generally quite low, we investigated the utility of the arcelin-5 regulatory sequences in obtaining high seed-specific expression in transgenic plants. Arcelin-5 is an abundant seed protein found in some wild common bean (Phaseolus vulgaris L.) genotypes. Seeds of Arabidopsis and Tepary bean (Phaseolus acutifolius A. Gray) plants transformed with arcelin-5 gene constructs synthesized arcelin-5 to levels of 15% and 25% of the total protein content, respectively. To our knowledge, such high expression levels directed by a transgene have not been reported before. The transgenic plants also showed low plant-to-plant variation in arcelin expression. Complex transgene integration patterns, which often result in gene silencing effects, were not associated with reduced arcelin-5 expression. High transgene expression was the result of high mRNA steady-state levels and was restricted to seeds. This indicates that all requirements for high seed-specific expression are cis elements present in the cloned genomic arcelin-5 sequence and trans-acting factors that are available in Arabidopsis and Phaseolus spp., and thus probably in most dicotyledonous plants.
许多编码种子贮藏蛋白的基因的调控序列已被用于驱动转基因植物中多种蛋白质的种子特异性表达。由于这些转基因衍生蛋白的积累水平通常相当低，我们研究了豆球蛋白-5调控序列在转基因植物中实现高种子特异性表达的效用。豆球蛋白-5是在一些野生普通菜豆（Phaseolus vulgaris L.）基因型中发现的一种丰富的种子蛋白。用豆球蛋白-5基因构建体转化的拟南芥和 tepary 豆（Phaseolus acutifolius A. Gray）植株的种子分别合成了占总蛋白含量15%和25%水平的豆球蛋白-5。据我们所知，此前尚未报道过由转基因引导的如此高的表达水平。转基因植株在豆球蛋白表达上还表现出较低的株间差异。通常会导致基因沉默效应的复杂转基因整合模式与豆球蛋白-5表达的降低无关。高转基因表达是高mRNA稳态水平的结果，并且仅限于种子。这表明高种子特异性表达的所有要求是克隆的基因组豆球蛋白-5序列中存在的顺式元件以及拟南芥和菜豆属中可用的反式作用因子，因此可能在大多数双子叶植物中也是如此。
