Bonneville J M, Sanfaçon H, Fütterer J, Hohn T
Friedrich Miescher-Institut, Basel, Switzerland.
Cell. 1989 Dec 22;59(6):1135-43. doi: 10.1016/0092-8674(89)90769-1.
The ability of plant cells to translate dicistronic mRNAs that mimic a segment of the polycistronic 35S RNA from cauliflower mosaic virus has been tested. The chloramphenicol acetyltransferase and beta-glucuronidase open reading frames (ORFs) were fused in-frame to the second viral cistron (ORF I). Efficient reporter expression from the corresponding plasmids in plant protoplasts was observed only upon cotransfection with viral DNA. The trans-activating gene maps at ORF VI, which is expressed from a separate, monocistronic messenger (19S RNA). Deletion analysis shows that trans-activation selectively enhances downstream gene expression; the high expression of the upstream ORF is not further increased. The major reporter transcript remained bicistronic upon trans-activation, and its abundance varied only to a limited extent. Results indicate that trans-activation enhances the translation of downstream ORFs on polycistronic mRNAs derived from cauliflower mosaic virus.
植物细胞翻译模拟花椰菜花叶病毒多顺反子35S RNA片段的双顺反子mRNA的能力已得到测试。氯霉素乙酰转移酶和β-葡萄糖醛酸酶开放阅读框（ORF）与第二个病毒顺反子（ORF I）框内融合。仅在与病毒DNA共转染时，才观察到植物原生质体中相应质粒的有效报告基因表达。反式激活基因定位于ORF VI，它由一个单独的单顺反子信使（19S RNA）表达。缺失分析表明，反式激活选择性地增强下游基因表达；上游ORF的高表达并未进一步增加。反式激活后，主要的报告基因转录本仍为双顺反子，其丰度仅在有限程度上有所变化。结果表明，反式激活增强了源自花椰菜花叶病毒的多顺反子mRNA上下游ORF的翻译。
