Sakai T, Takahashi Y, Nagata T
Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan.
Plant Cell Physiol. 1996 Oct;37(7):906-13. doi: 10.1093/oxfordjournals.pcp.a029038.
The auxin-responsive region (AuxRR) in the promoter of the parC gene was analyzed in transgenic tobacco plants in which the 5' flanking region of the parC promoter was placed upstream of the gene for beta-glucuronidase (GUS). The AuxRR was located between nucleotides (nt) -226 and -54. Detailed dissection of this segment revealed that the presence of the non-contiguous sequences from nt -226 to -151 and from nt -84 to -54 was required for the expression of the auxin responsiveness of the parC promoter. The sequence from nt -226 to -151 was found to contain a sequence which resembles the as-1 element in the 35S promoter of cauliflower mosaic virus (CaMV). Although it has been reported that the as-1 element is involved in auxin responsiveness [Liu and Lam (1994) J. Biol. Chem. 269: 668], we showed that introduction of a point mutation into the as-1-like sequence completely eliminated auxin responsiveness, a result that suggests that the sequence is indispensable for auxin responsiveness. However, the presence of the as-1-like sequence alone was not sufficient for auxin responsiveness, since the segment (nt -226 to -84) that included the as-1-like sequence failed to confer auxin responsiveness on the core promoter. It is possible that the two separately located sequences play specific roles in interactions with trans-factors that are required for the expression of the auxin responsiveness of the parC promoter.
在转基因烟草植株中分析了parC基因启动子中的生长素响应区域（AuxRR），其中parC启动子的5'侧翼区域位于β-葡萄糖醛酸酶（GUS）基因的上游。AuxRR位于核苷酸（nt）-226至-54之间。对该片段的详细剖析表明，parC启动子生长素响应性的表达需要存在从nt -226至-151和从nt -84至-54的非连续序列。发现从nt -226至-151的序列包含一个类似于花椰菜花叶病毒（CaMV）35S启动子中as-1元件的序列。尽管已有报道as-1元件参与生长素响应性[Liu和Lam（1994）J. Biol. Chem. 269: 668]，但我们表明在as-1样序列中引入点突变完全消除了生长素响应性，这一结果表明该序列对于生长素响应性是不可或缺的。然而，仅as-1样序列的存在不足以产生生长素响应性，因为包含as-1样序列的片段（nt -226至-84）未能赋予核心启动子生长素响应性。有可能这两个分开定位的序列在与parC启动子生长素响应性表达所需的反式因子相互作用中发挥特定作用。
