Lebendiker M A, Tal C, Sayar D, Pilo S, Eilon A, Banai Y, Kaempfer R
EMBO J. 1987 Mar;6(3):585-9. doi: 10.1002/j.1460-2075.1987.tb04794.x.
Mitogen-induced interferon-gamma (IFN-gamma) gene expression was analyzed in human tonsil cells by titration of IFN-gamma activity and by quantitation of IFN-gamma mRNA. Expression of the IFN-gamma gene can be superinduced extensively by two distinct methods: exposure to various inhibitors of translation, or to low doses of gamma-irradiation. gamma-Irradiated cells produce, after exposure to cycloheximide, up to 12-fold greater amounts of IFN-gamma activity. Within as little as 4 h after the addition of translation inhibitors, IFN-gamma mRNA levels rise 3- to 5-fold. Superinduction acts to increase the size of the wave of IFN-gamma mRNA. Primary transcription of the IFN-gamma gene does not increase in cells superinduced by cycloheximide, nor can superinduction be explained by stabilization of IFN-gamma mRNA sequences. These findings show that, during normal induction, a labile protein acts post-transcriptionally to repress the accumulation of mature IFN-gamma mRNA sequences. The superinductive effects of cycloheximide and gamma-irradiation on levels of IFN-gamma are additive, suggesting that they affect different aspects of IFN-gamma gene expression. Superinduction by gamma-irradiation also has a post-transcriptional basis and is consistent with the possibility that expression of the IFN-gamma gene is normally controlled by the action of suppressor T cells. Even though the genes for human IFN-gamma and for interleukin-2 are both superinducible, a striking difference in the regulation of expression of these lymphokine genes is observed. Superinduction of IFN-gamma mRNA is not due to superinduction of interleukin-2.
通过滴定干扰素-γ（IFN-γ）活性和定量IFN-γ mRNA，分析了丝裂原诱导的人扁桃体细胞中IFN-γ基因的表达。IFN-γ基因的表达可以通过两种不同的方法被广泛超诱导：暴露于各种翻译抑制剂或低剂量的γ射线照射。γ射线照射的细胞在暴露于环己酰亚胺后，产生的IFN-γ活性高达12倍。在添加翻译抑制剂后短短4小时内，IFN-γ mRNA水平就会升高3至5倍。超诱导作用是增加IFN-γ mRNA的波动幅度。在经环己酰亚胺超诱导的细胞中，IFN-γ基因的初级转录没有增加，超诱导也不能用IFN-γ mRNA序列的稳定来解释。这些发现表明，在正常诱导过程中，一种不稳定的蛋白质在转录后发挥作用，抑制成熟IFN-γ mRNA序列的积累。环己酰亚胺和γ射线照射对IFN-γ水平的超诱导作用是相加的，这表明它们影响IFN-γ基因表达的不同方面。γ射线照射的超诱导也有转录后基础，并且与IFN-γ基因表达通常受抑制性T细胞作用控制的可能性一致。尽管人类IFN-γ基因和白细胞介素-２基因都可被超诱导，但在这些淋巴因子基因表达的调控中观察到了显著差异。IFN-γ mRNA的超诱导不是由于白细胞介素-２的超诱导。
