Fütterer J, Gordon K, Pfeiffer P, Sanfaçon H, Pisan B, Bonneville J M, Hohn T
Friedrich Miescher-Institut, Basel, Switzerland.
Virus Genes. 1989 Sep;3(1):45-55. doi: 10.1007/BF00301986.
The effect of the 600 nucleotide-long CaMV 35S RNA 5' leader sequence on the expression of downstream genes was analyzed both in plant protoplasts and in vitro. For transient expression studies in protoplasts derived from host and nonhost plants, the bacterial chloramphenicol acetyl transferase (CAT) gene was fused to the initiation codon of ORF VII. The leader sequence reduced CAT expression two- to four-fold in protoplasts derived from three host species, but 10- to 50-fold in protoplasts derived from three different nonhost species. For in-vitro studies the 35S promoter was replaced by the SP6 promoter. The leader reduced in-vitro translation of SP6 transcripts approximately six-fold, indicating that at least part of the inhibition observed in protoplasts is directly due to the interference of the leader sequence with translation. Other steps in gene expression that may also be affected are discussed.
在植物原生质体和体外环境中，均对长度为600个核苷酸的花椰菜花叶病毒35S RNA 5'前导序列对下游基因表达的影响进行了分析。为了在源自宿主植物和非宿主植物的原生质体中进行瞬时表达研究，将细菌氯霉素乙酰转移酶（CAT）基因与开放阅读框VII的起始密码子融合。该前导序列使源自三种宿主物种的原生质体中的CAT表达降低了2至4倍，但在源自三种不同非宿主物种的原生质体中降低了10至50倍。对于体外研究，将35S启动子替换为SP6启动子。该前导序列使SP6转录本的体外翻译降低了约6倍，这表明在原生质体中观察到的至少部分抑制作用直接归因于前导序列对翻译的干扰。文中还讨论了基因表达中其他可能受到影响的步骤。
