Medberry S L, Olszewski N E
Department of Plant Biology, University of Minnesota, St. Paul 55108.
Plant J. 1993 Apr;3(4):619-26. doi: 10.1046/j.1365-313x.1993.03040619.x.
Commelina yellow mottle virus (CoYMV) is a double-stranded DNA virus that infects a monocot host. A promoter fragment isolated from CoYMV is a strong promoter when assayed after transient introduction into monocot and dicot suspension cells and is highly active in vascular cells of flowers, leaves, stems and roots of stably transformed tobacco plants. Here it is reported that in stably transformed maize calli and transgenic tobacco leaves the CoYMV and CaMV 35S promoters exhibit similar amounts of activity. Deletion of the sequences located distal to nucleotide -230 relative to the start of transcription has no significant effect on promoter strength or tissue specificity. The region between -230 and -200 shares sequence similarity with the as-1 promoter element of the CaMV 35S promoter. Deletion of this as-1-like motif decreases promoter activity in maize suspension cells by 85%. Analysis of deletions affecting the -200 to -52 region indicates that sequences located between -159 and -84 are required for activity in vascular tissues. In addition, this region exhibits properties of a vascular tissue-specific enhancer since it confers vascular expression in an orientation-independent manner when fused to promoters that are not normally active in vascular tissues.
鸭跖草黄斑驳病毒（CoYMV）是一种感染单子叶植物宿主的双链DNA病毒。从CoYMV分离出的一个启动子片段，在瞬时导入单子叶和双子叶悬浮细胞后进行检测时是一个强启动子，并且在稳定转化的烟草植株的花、叶、茎和根的维管细胞中具有高活性。本文报道，在稳定转化的玉米愈伤组织和转基因烟草叶片中，CoYMV启动子和花椰菜花叶病毒35S启动子（CaMV 35S启动子）表现出相似的活性水平。相对于转录起始点，缺失核苷酸-230远端的序列对启动子强度或组织特异性没有显著影响。-230至-200之间的区域与CaMV 35S启动子的as-1启动子元件具有序列相似性。缺失这个类as-1基序会使玉米悬浮细胞中的启动子活性降低85%。对影响-200至-52区域的缺失分析表明，-159至-84之间的序列是维管组织中启动子活性所必需的。此外，该区域表现出维管组织特异性增强子的特性，因为当它与通常在维管组织中无活性的启动子融合时，能以不依赖方向的方式赋予维管组织表达。
