Friedrich Miescher-Institut, P.O.Box 2543, CH-4002 Basel, Switzerland.
EMBO J. 1984 Dec 1;3(12):2731-6. doi: 10.1002/j.1460-2075.1984.tb02203.x.
Mutants with deletions in the open reading frame (ORF) VII to I region of the cauliflower mosaic virus genome were constructed in vitro and tested for infectivity by inoculation of plants. Sequences within ORF VII and the intergenomic region between ORFs VII and I are not required for viral infectivity. Nevertheless, the location of translation initiation and termination codons within this region governs the infectivity of the virus. Firstly, translation beginning at the initiation codon of ORF VII should reach an in-phase termination codon before the initiation codon of ORF I. Secondly, an initiation codon should be located in the vicinity of the sequence homologous to methionine tRNA, the proposed primer binding site for reverse transcription. Results suggest translation from a polycistronic mRNA by a ;relay race' mechanism whereby ribosomes after passing a termination codon re-initiate protein synthesis at the nearest AUG codon.
体外构建了缺失花椰菜花叶病毒基因组开放阅读框（ORF）VII 到 I 区的突变体，并通过接种植物来测试其感染性。ORF VII 内的序列和 ORFs VII 和 I 之间的基因组间区域对于病毒感染性不是必需的。然而，该区域中翻译起始和终止密码子的位置决定了病毒的感染性。首先，ORF VII 的起始密码子开始的翻译应该在 ORF I 的起始密码子之前达到同相终止密码子。其次，起始密码子应该位于与甲硫氨酸 tRNA 同源的序列附近，该序列是反转录的提议引物结合位点。结果表明，通过“接力赛跑”机制从多顺反子 mRNA 进行翻译，其中核糖体在通过终止密码子后，在最近的 AUG 密码子处重新起始蛋白质合成。
