Chalbos D, Crépin M, Lebleu B
J Gen Virol. 1982 Sep;62 (Pt 1):65-80. doi: 10.1099/0022-1317-62-1-65.
The effects of interferon treatment on the expression of murine mammary tumour virus (MuMTV) by a continuous mammary tumour cell line of GR mouse were investigated. Interferon markedly inhibited the excretion of MuMTV particles in the culture media as measured by hybridization of virus-specific RNA and virus-associated reverse transcriptase activity. There was no inhibition of virus RNA and protein synthesis in those conditions. The steady-state level of intracellular virus RNA and its rate of synthesis were not modified by interferon treatment. The intracellular levels of the major virus envelope and core proteins as measured by immunoprecipitation techniques remained unchanged. Interferon failed to inhibit the synthesis and the processing of the gp52 glycoprotein and p27 core protein precursors. However, the rate of maturation of the glycoprotein precursor was slowed down. Surface labelling of intact cells did not reveal accumulation of virus proteins on the cell membrane upon interferon treatment. The intracellular level of MuMTV-characteristic reverse transcriptase activity was reduced in interferon treated cells, although to a lower extent than extracellular virion-associated enzyme activity. MuMTV particles released from interferon-treated cells revealed no difference in their protein composition. These results are consistent with an inhibition by interferon of a late step in the replication of MuMTV.
研究了干扰素处理对GR小鼠连续乳腺肿瘤细胞系中鼠乳腺肿瘤病毒（MuMTV）表达的影响。通过病毒特异性RNA杂交和病毒相关逆转录酶活性测定，干扰素显著抑制了培养基中MuMTV颗粒的排泄。在这些条件下，病毒RNA和蛋白质合成未受抑制。干扰素处理未改变细胞内病毒RNA的稳态水平及其合成速率。通过免疫沉淀技术测定的主要病毒包膜和核心蛋白的细胞内水平保持不变。干扰素未能抑制gp52糖蛋白和p27核心蛋白前体的合成与加工。然而，糖蛋白前体的成熟速率减慢。完整细胞的表面标记未显示干扰素处理后病毒蛋白在细胞膜上的积累。干扰素处理的细胞中MuMTV特征性逆转录酶活性的细胞内水平降低，尽管程度低于细胞外病毒粒子相关酶活性。从干扰素处理的细胞中释放的MuMTV颗粒在蛋白质组成上没有差异。这些结果与干扰素对MuMTV复制后期步骤的抑制作用一致。
