Nilsen T W, Weissman S G, Baglioni C
Biochemistry. 1980 Nov 25;19(24):5574-9. doi: 10.1021/bi00565a018.
RNA covalently linked to double-stranded RNA (dsRNA) is preferentially degraded in extracts of interferon-treated HeLa cells [Nilsen, T. W., & Baglioni, C. (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 2600-2604]. The size of the dsRNA required for this preferential degradation has been determined by annealing poly(I) of known length to the poly(C) tract of encephalomyocarditis virus (EMCV) RNA or by annealing poly(U) to poly(A) of known length of vesicular stomatitis virus mRNA. The dsRNA must be longer than about 60 base pairs to observe the preferential degradation of RNA. Moreover, triple-stranded regions that do not activate synthesis of 2',5'-oligo(A) and ethidium bromide, which intercalates in dsRNA and blocks 2',5'-olido(A) polymerase activation, prevent this degradation. Ethidium also blocks the degradation of the replicative intermediate of EMCV by extracts of interferon-treated cells. These experiments indicate that synthesis of 2',5'-oligo(A) is required for the degradation of RNA linked to dsRNA. The 2',5'-oligo(A)-dependent endonuclease does not cleave single- or double-stranded DNA, nor does it cleave homopolyribonucleotides. The potential role of the 2',5'-oligo(A) polymerase/endonuclease system in the inhibition of viral RNA replication is discussed.
与双链RNA（dsRNA）共价连接的RNA在经干扰素处理的HeLa细胞提取物中优先被降解[Nilsen, T. W., & Baglioni, C. (1979) Proc. Natl. Acad. Sci. U.S.A. 76, 2600 - 2604]。通过将已知长度的聚（I）与脑心肌炎病毒（EMCV）RNA的聚（C）区段退火，或通过将聚（U）与水疱性口炎病毒mRNA已知长度的聚（A）退火，已确定了这种优先降解所需的dsRNA大小。dsRNA必须长于约60个碱基对才能观察到RNA的优先降解。此外，不激活2',5'-寡聚腺苷酸合成的三链区以及嵌入dsRNA并阻断2',5'-寡聚腺苷酸聚合酶激活的溴化乙锭可阻止这种降解。溴化乙锭还可阻断经干扰素处理的细胞提取物对EMCV复制中间体的降解。这些实验表明，2',5'-寡聚腺苷酸的合成是与dsRNA连接的RNA降解所必需的。2',5'-寡聚腺苷酸依赖性内切核酸酶不切割单链或双链DNA，也不切割同聚核糖核苷酸。讨论了2',5'-寡聚腺苷酸聚合酶/内切核酸酶系统在抑制病毒RNA复制中的潜在作用。
