Fütterer J, Gordon K, Sanfaçon H, Bonneville J M, Hohn T
Friedrich Miescher-Institut, Basel, Switzerland.
EMBO J. 1990 Jun;9(6):1697-707. doi: 10.1002/j.1460-2075.1990.tb08293.x.
We have studied the influence of the 600 nt long leader sequence of cauliflower mosaic virus 35S RNA on downstream translation. Plant protoplasts were transfected with plasmids expressing a CAT reporter gene from a mRNA, containing wild-type or mutant forms of the 35S RNA leader. Deletion analysis revealed the presence of three separate stimulatory sequence regions, S1, S2 and S3. The latter two interact with each other to enhance downstream translation 5- to 10-fold. This enhancement was not observed in protoplasts from a non-host plant. In the absence of either S2 or S3, the region I2, located in between, exerts an inhibitory effect on downstream translation, probably due to the presence of short open reading frames. Expression of a reporter gene inserted into I2 increases 2-fold upon deletion of either S2 or S3. We propose that mRNA regions S2 and S3 form a complex with cellular factors that allows scanning ribosomes to bypass region I2.
我们研究了花椰菜花叶病毒35S RNA的600个核苷酸长的前导序列对下游翻译的影响。用表达来自含有35S RNA前导序列野生型或突变型的mRNA的CAT报告基因的质粒转染植物原生质体。缺失分析揭示了存在三个独立的刺激序列区域，即S1、S2和S3。后两个区域相互作用，使下游翻译增强5至10倍。在非寄主植物的原生质体中未观察到这种增强作用。在没有S2或S3的情况下，位于其间的I2区域对下游翻译产生抑制作用，这可能是由于存在短开放阅读框。当缺失S2或S3时，插入I2的报告基因的表达增加2倍。我们提出，mRNA区域S2和S3与细胞因子形成复合物，使扫描核糖体能够绕过I2区域。
