Jonak G J, Friedland B K, Anton E D, Knight E
J Interferon Res. 1987 Feb;7(1):41-52. doi: 10.1089/jir.1987.7.41.
It has been shown previously that interferons (IFNs) -alpha and -beta cause a reduction in the steady-state level of poly(A) c-myc RNA in the Burkitt lymphoma, Daudi. In this report we show that the c-myc RNA reduction is not mediated by simple changes in the poly-adenylation of either nascent or existing c-myc transcripts, since similar reductions of c-myc sequences were observed in poly(A) and total cellular RNA preparations from IFN-beta-treated cells. Furthermore, the first exon of c-myc RNA in Daudi cells contains several mutations, suggesting that the germ line configuration of the first exon is not essential for the IFN-beta-mediated regulation. The c-myc RNA reduction was also detected in cells whose protein synthesis was inhibited by more than 95% with cycloheximide or emetine. We surmise that neither sustained nor IFN-induced protein synthesis is required for the c-myc RNA regulation. Antisera raised against either the carboxy- or amino-terminal c-myc peptides precipitate in Daudi cells proteins of 66,000 and 63,000 daltons. In cells treated with IFN-beta, the amounts of these proteins are reduced by 46-74% which is in agreement with the reduction detected at the level of c-myc RNA.
先前的研究表明，α干扰素（IFN）和β干扰素可使伯基特淋巴瘤细胞系Daudi中聚腺苷酸化的c-myc RNA的稳态水平降低。在本报告中，我们发现c-myc RNA的减少并非由新生或现有c-myc转录本的多聚腺苷酸化的简单变化介导，因为在经β干扰素处理的细胞的聚腺苷酸化RNA和总细胞RNA制剂中观察到了类似的c-myc序列减少。此外，Daudi细胞中c-myc RNA的第一个外显子包含几个突变，这表明第一个外显子的种系构型对于β干扰素介导的调控并非必不可少。在用环己酰亚胺或依米丁将蛋白质合成抑制95%以上的细胞中也检测到了c-myc RNA的减少。我们推测，c-myc RNA的调控既不需要持续的蛋白质合成，也不需要干扰素诱导的蛋白质合成。针对c-myc羧基末端或氨基末端肽产生的抗血清可沉淀Daudi细胞中66,000和63,000道尔顿的蛋白质。在用β干扰素处理的细胞中，这些蛋白质的量减少了46%-74%，这与在c-myc RNA水平检测到的减少一致。
