Chen M H, Roossinck M J, Kao C C
Department of Biology, Indiana University, Bloomington, Indiana 47405, USA.
J Virol. 2000 Dec;74(23):11201-9. doi: 10.1128/jvi.74.23.11201-11209.2000.
We defined the minimal core promoter sequences responsible for efficient and accurate initiation of cucumber mosaic virus (CMV) subgenomic RNA4. The necessary sequence maps to positions -28 to +15 relative to the initiation cytidylate used to initiate RNA synthesis in vivo. Positions -28 to -5 contain a 9-bp stem and a 6-nucleotide purine-rich loop. Considerable changes in the stem and the loop are tolerated for RNA synthesis, including replacement with a different stem-loop. In a template competition assay, the stem-loop and the initiation cytidylate are sufficient to interact with the CMV replicase. Thus, the mechanism of core promoter recognition by the CMV replicase appears to be less specific in comparison to the minimal subgenomic core promoter of the closely related brome mosaic virus.
我们确定了负责黄瓜花叶病毒(CMV)亚基因组RNA4高效准确起始的最小核心启动子序列。必要序列相对于体内用于起始RNA合成的起始胞苷酸定位在-28至+15位。-28至-5位包含一个9碱基对的茎和一个6核苷酸富含嘌呤的环。RNA合成可耐受茎和环的相当大变化,包括用不同的茎环替换。在模板竞争试验中,茎环和起始胞苷酸足以与CMV复制酶相互作用。因此,与密切相关的雀麦花叶病毒的最小亚基因组核心启动子相比,CMV复制酶识别核心启动子的机制似乎特异性较低。