Kawakami K, Mizumoto K, Ishihama A
Nucleic Acids Res. 1983 Jun 11;11(11):3637-49. doi: 10.1093/nar/11.11.3637.
Catalytic properties of the capped RNA-specific endonuclease associated with the influenza virus RNA polymerase were analyzed with use of synthetic hetero- and homopolymers containing 32P-labeled CAP structures at their 5' termini. The endonuclease displays its intrinsic activity provided that substrate RNA contains both the CAP-1 structure (m7GpppGm) and either A or U residues at 9 to 11 nucleotides distant from the CAP structure. Independent recognition of multiple RNA signals by the endonuclease was further supported by the findings that dinucleotide ApG, free CAP structures and RNA without the CAP structure inhibited the endonuclease activity to different extents. In the presence of four species of ribonucleoside 5'-triphosphates, the endonucleolytically cleaved fragments with the CAP-1 structure were incorporated into polynucleotides, supporting the concept that they are used as the primers for the transcription. The initial nucleotide linked to the primers was a G residue, the nucleotide complementary to the second base of the 3' termini of the vRNA segments.
利用在其5'末端含有32P标记的帽结构的合成杂聚物和同聚物，分析了与流感病毒RNA聚合酶相关的带帽RNA特异性核酸内切酶的催化特性。只要底物RNA同时含有帽-1结构（m7GpppGm）以及在距帽结构9至11个核苷酸处的A或U残基，该核酸内切酶就会表现出其内在活性。核酸内切酶对多种RNA信号的独立识别进一步得到以下发现的支持：二核苷酸ApG、游离帽结构和无帽结构的RNA在不同程度上抑制核酸内切酶活性。在四种核糖核苷5'-三磷酸存在的情况下，具有帽-1结构的核酸内切酶切割片段被掺入多核苷酸中，这支持了它们被用作转录引物的概念。与引物相连的第一个核苷酸是G残基，它是与vRNA片段3'末端第二个碱基互补的核苷酸。
