Groeneveld H, Oudot F, van Duin J V
Leiden Institute of Chemistry, University of Leiden, Leiden, 2300 RA, The Netherlands.
Virology. 1996 Apr 1;218(1):141-7. doi: 10.1006/viro.1996.0174.
We have determined the nucleotide sequence of group II RNA phage KU1. The most conspicuous difference in the comparison with other group II members such as GA and JP34 is the presence of an insertion in the start codon of the lysis gene. In GA and JP34, the coat and lysis genes overlap by one nucleotide in the configuration UAAUG. The 18-nt insertion in KU1 is positioned between the A and the U of the start codon. It does not affect the coat reading frame, but it destroys the AUG start codon and separates the previously overlapping genes by 17 nts. The insert creates a UUG codon at its 3' border which serves as the start site for lysis protein synthesis in KU1. We also show that analogous to the group I phages, such as MS2 and fr, expression of the lysis gene in KU1 and JP34 is coupled to termination of translation at the coat gene. RNA secondary structure models for the central parts of KU1 and JP34 are suggested which can account for the insertion as a separate stem-loop structure.
我们已经确定了II组RNA噬菌体KU1的核苷酸序列。与其他II组成员（如GA和JP34）相比，最显著的差异在于裂解基因起始密码子处存在一个插入序列。在GA和JP34中，衣壳基因和裂解基因以UAAUG的形式重叠一个核苷酸。KU1中的18个核苷酸插入序列位于起始密码子的A和U之间。它不影响衣壳阅读框，但破坏了AUG起始密码子，并使先前重叠的基因相隔17个核苷酸。该插入序列在其3'边界处产生一个UUG密码子，作为KU1中裂解蛋白合成的起始位点。我们还表明，与I组噬菌体（如MS2和fr）类似，KU1和JP34中裂解基因的表达与衣壳基因处的翻译终止相偶联。我们提出了KU-1和JP34中心部分的RNA二级结构模型，该模型可以将插入序列解释为一个单独的茎环结构。
