Schirawski J, Voyatzakis A, Zaccomer B, Bernardi F, Haenni A L
Institut Jacques Monod, 75251 Paris Cedex 05, France.
J Virol. 2000 Dec;74(23):11073-80. doi: 10.1128/jvi.74.23.11073-11080.2000.
Most plant viruses rely on the production of subgenomic RNAs (sgRNAs) for the expression of their genes and survival in the plant. Although this is a widely adopted strategy among viruses, the mechanism(s) whereby sgRNA production occurs remains poorly defined. Turnip yellow mosaic tymovirus (TYMV) is a positive-stranded RNA virus that produces an sgRNA for the expression of its coat protein. Here we report that the subgenomic promoter sequence of TYMV is located on a 494-nucleotide fragment, containing previously identified highly conserved sequence elements, which are shown here to be essential for promoter function. After duplication, the subgenomic promoter can be inserted into the coat protein open reading frame, giving rise to the in vivo production of a second sgRNA. It is suggested that this promoter can function when contained on a different molecule than viral genomic RNA. This interesting trait may be of general use for plant and plant virus research.
大多数植物病毒依靠亚基因组RNA（sgRNA）的产生来表达其基因并在植物中存活。尽管这是病毒中广泛采用的一种策略，但sgRNA产生的机制仍不清楚。芜菁黄花叶病毒（TYMV）是一种正链RNA病毒，它产生一种sgRNA来表达其外壳蛋白。在此我们报道，TYMV的亚基因组启动子序列位于一个494个核苷酸的片段上，该片段包含先前鉴定出的高度保守的序列元件，本文显示这些元件对启动子功能至关重要。复制后，亚基因组启动子可插入外壳蛋白开放阅读框，从而在体内产生第二种sgRNA。有人认为，当该启动子包含在与病毒基因组RNA不同的分子上时也能发挥作用。这一有趣的特性可能在植物和植物病毒研究中具有普遍用途。
