Ha S B, An G H
Institute of Biological Chemistry, Washington State University, Pullman 99164-6340.
Nucleic Acids Res. 1989 Jan 11;17(1):215-23. doi: 10.1093/nar/17.1.215.
Regulatory elements controlling temporal and organ-specific expression of the nopaline (nos) gene were identified by analyzing deletion mutants of the promoter. As observed in cultured cells, the TATA box element was required for efficient promoter function and the 29 bp upstream promoter region between -130 and -101 was necessary for the nos promoter activity in various vegetative organs. This 29 bp region includes ten nucleotides of a potential Z-DNA-forming sequence (Z element) and eight nucleotides of a repeated element (b element). Duplication of b elements significantly enhanced the promoter strength, revealing the importance of the element in all plant organs. Unlike the results in the cultured cells, however, deletion of the b element or CCAAT box region completely inactivated the promoter function in regenerated organs. Therefore, it appears that transcription initiation is more tightly controlled in differentiated plant cells than in cultured cells.
通过分析胭脂碱（nos）基因启动子的缺失突变体，确定了控制该基因时间和器官特异性表达的调控元件。如在培养细胞中观察到的，TATA盒元件对于有效的启动子功能是必需的，并且-130至-101之间的29bp上游启动子区域对于nos启动子在各种营养器官中的活性是必需的。这个29bp区域包括一个潜在的Z-DNA形成序列（Z元件）的十个核苷酸和一个重复元件（b元件）的八个核苷酸。b元件的重复显著增强了启动子强度，揭示了该元件在所有植物器官中的重要性。然而，与培养细胞中的结果不同，b元件或CCAAT盒区域的缺失完全使再生器官中的启动子功能失活。因此，似乎转录起始在分化的植物细胞中比在培养细胞中受到更严格的控制。
