Marshall J. S., Stubbs J. D., Chitty J. A., Surin B., Taylor W. C.
CSIRO Plant Industry, GPO Box 1600, Canberra 2601, Australia.
Plant Cell. 1997 Sep;9(9):1515-1525. doi: 10.1105/tpc.9.9.1515.
The efficient functioning of C4 photosynthesis requires the strict compartmentation of a suite of enzymes in either mesophyll or bundle sheath cells. To determine the mechanism controlling bundle sheath cell-specific expression of the NADP-malic enzyme, we made a set of chimeric constructs using the 5[prime] and 3[prime] regions of the Flaveria bidentis Me1 gene fused to the [beta]-glucuronidase gusA reporter gene. The pattern of GUS activity in stably transformed F. bidentis plants was analyzed by histochemical and cell separation techniques. We conclude that the 5[prime] region of Me1 determines bundle sheath specificity, whereas the 3[prime] region contains an apparent enhancer-like element that confers high-level expression in leaves. The interaction of 5[prime] and 3[prime] sequences was dependent on factors that are present in the C4 plant but not found in tobacco.
C4光合作用的高效运行需要一系列酶在叶肉细胞或维管束鞘细胞中严格区室化。为了确定控制维管束鞘细胞特异性表达NADP-苹果酸酶的机制，我们构建了一组嵌合构建体，使用双齿黄菊（Flaveria bidentis）Me1基因的5′和3′区域与β-葡萄糖醛酸酶gusA报告基因融合。通过组织化学和细胞分离技术分析了稳定转化的双齿黄菊植株中GUS活性的模式。我们得出结论，Me1的5′区域决定了维管束鞘特异性，而3′区域包含一个明显的增强子样元件，可赋予叶片高水平表达。5′和3′序列的相互作用取决于C4植物中存在但烟草中未发现的因子。
