Tiwari R K, Kusari J, Kumar R, Sen G C
Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
Mol Cell Biol. 1988 Oct;8(10):4289-94. doi: 10.1128/mcb.8.10.4289-4294.1988.
Transcription of several interferon-inducible human genes is also induced by double-stranded RNA. The nature and the mechanism of action of signals generated by interferons and by double-stranded RNA which mediate the induction of these genes are under investigation. Here we report that 2-aminopurine, a known inhibitor of protein kinases, could selectively block this induction process. Induction of mRNAs 561 and 6-16 in HeLaM cells by double-stranded RNA was completely inhibited by 10 mM 2-aminopurine, whereas cellular protein and RNA syntheses as well as the induction of metallothionein mRNA by CdCl2 were unaffected by this inhibitor. In addition, 2-aminopurine blocked the induction of the same two mRNAs and of mRNAs 2-5(A) synthetase, 2A, and 1-8 by alpha interferon and of mRNAs 2A and 1-8 by gamma interferon in HeLaM cells. The observed inhibition was at the level of transcription, and for establishing efficient inhibition, the 2-aminopurine treatment had to begin at early stages of interferon treatment. In GM2767 cells, 2-aminopurine inhibited induction of mRNAs 561 and 6-16 by double-stranded RNA but not by alpha interferon. These results suggest that double-stranded RNA-induced signal 2 is distinct from the interferon-alpha-induced signal 2 (R. K. Tiwari, J. Kusari, and G. C. Sen, EMBO J. 6:3373-3378, 1987) and that 2-aminopurine can block the former but not the latter. Moreover, it appeared that 2-aminopurine could block the production of signal 1 by interferons. This was confirmed by experiments in which we separately tested the effects of 2-aminopurine on signal 1 and signal 2 production by interferons in HeLaM cells. Although no direct experimental evidence is available as yet, our results are consistent with the hypothesis that the functioning of a protein kinase activity may be necessary for transcriptional induction of genes by double-stranded RNA and for gene induction by interferons in those cells in which signal 1 production is needed.
几种干扰素诱导的人类基因的转录也可由双链RNA诱导。介导这些基因诱导的干扰素和双链RNA产生的信号的性质和作用机制正在研究中。在此我们报告，已知的蛋白激酶抑制剂2-氨基嘌呤可选择性地阻断这一诱导过程。10 mM 2-氨基嘌呤可完全抑制双链RNA对HeLaM细胞中mRNA 561和6-16的诱导，而细胞蛋白质和RNA合成以及CdCl2对金属硫蛋白mRNA的诱导不受该抑制剂影响。此外，2-氨基嘌呤可阻断α干扰素对HeLaM细胞中相同的两种mRNA以及mRNA 2-5(A)合成酶、2A和1-8的诱导，以及γ干扰素对mRNA 2A和1-8的诱导。观察到的抑制作用发生在转录水平，为建立有效的抑制，2-氨基嘌呤处理必须在干扰素处理的早期开始。在GM2767细胞中，2-氨基嘌呤可抑制双链RNA对mRNA 561和6-16的诱导，但不能抑制α干扰素的诱导。这些结果表明，双链RNA诱导的信号2与α干扰素诱导的信号2不同（R. K. Tiwari、J. Kusari和G. C. Sen，《欧洲分子生物学组织杂志》6:3373 - 3378，1987），且2-氨基嘌呤可阻断前者而非后者。此外，似乎2-氨基嘌呤可阻断干扰素产生信号1。这在我们分别测试2-氨基嘌呤对HeLaM细胞中干扰素产生信号1和信号2的影响的实验中得到了证实。尽管目前尚无直接的实验证据，但我们的结果与以下假设一致，即蛋白激酶活性的发挥可能是双链RNA转录诱导基因以及在需要产生信号1的细胞中干扰素诱导基因所必需的。
