Kim Y, Buckley K, Costa M A, An G
Institute of Biological Chemistry, Washington State University, Pullman 99164-6340.
Plant Mol Biol. 1994 Jan;24(1):105-17. doi: 10.1007/BF00040578.
The nopaline synthase (nos) promoter is expressed in a wide range of plant cell types and regulated by various developmental and environmental factors. The nos upstream control region essential for this regulation was studied by means of synthetic oligomers using transient and stable transformation systems. Insertion of a 20 nucleotide sequence containing two hexamer motifs and a spacer region into deletion mutants lacking the upstream control region was essential for promoter activity. Mutation of one or more nucleotides of either hexamer sequence significantly altered the strength of expression of the nos promoter. Point mutations within the spacer region also strongly influenced promoter strength. Insertion of multiple copies of the 20 nucleotide sequence into the nonfunctional deletion mutants proportionally increased the promoter activity. These results suggest that this twenty nucleotide sequence is essential for the nos promoter to function. Substitution of the nos element with the ocs or 35S as-1 which contain similar hexamer motifs restored not only promoter activity but also responses to wounding, auxin, methyl jasmonate, and salicylic acid.
胭脂碱合成酶（nos）启动子在多种植物细胞类型中表达，并受多种发育和环境因素调控。利用瞬时和稳定转化系统，通过合成寡聚物对该调控所必需的nos上游控制区进行了研究。将包含两个六聚体基序和一个间隔区的20个核苷酸序列插入缺乏上游控制区的缺失突变体中，对启动子活性至关重要。任一六聚体序列中一个或多个核苷酸的突变显著改变了nos启动子的表达强度。间隔区内的点突变也强烈影响启动子强度。将20个核苷酸序列的多个拷贝插入无功能的缺失突变体中，可按比例增加启动子活性。这些结果表明，这20个核苷酸序列对nos启动子发挥功能至关重要。用含有相似六聚体基序的ocs或35S as-1取代nos元件，不仅恢复了启动子活性，还恢复了对创伤、生长素、茉莉酸甲酯和水杨酸的响应。
