The cytotoxicity of the parvovirus minute virus of mice nonstructural protein NS1 is related to changes in the synthesis and phosphorylation of cell proteins
The cytotoxicity of the parvovirus minute virus of mice nonstructural protein NS1 is related to changes in the synthesis and phosphorylation of cell proteins
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DOI：
10.1128/jvi.71.6.4671-4678.1997
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发表时间：
1997-06-01
影响因子：
5.4
通讯作者：
CailletFauquet, P
中科院分区：
文献类型：
--
作者：
Anouja, F;Wattiez, R;CailletFauquet, P
自主细小病毒发挥裂解和细胞抑制作用，被认为有助于其增殖活性。诱导型克隆的研究表明细小病毒非结构蛋白（NS）直接参与溶瘤作用。人和大鼠成纤维细胞已稳定转染MVM（p）（小鼠原型株的微小病毒）NS基因克隆下的病毒诱导型启动子的控制下。地塞米松诱导的NS蛋白在敏感转化细胞中的合成在几天内导致细胞杀伤。从这些敏感细胞系中分离出一些NS抗性克隆，它们也证明对MVM（p）感染具有抗性，这表明细胞因子调节NS细胞毒性。我们以前曾报道，参与细胞周期调控的因素可能有助于这种调节，因为NS毒性需要细胞增殖，并与细胞周期扰动相关，导致S/G期阻滞（2）。除了其在细胞毒性中的作用，NS 1可以调节由细小病毒和非细小病毒启动子驱动的转录。由于磷酸化是控制许多蛋白质，特别是转录因子和细胞周期调节蛋白的活性的关键事件，我们已经研究了NS 1对细胞蛋白质的合成和磷酸化的影响。我们的研究结果表明，NS 1干扰，在7小时内的诱导，与磷酸化的蛋白质约14 kDa（p14）。细胞同步化使我们能够表明，这种蛋白质的磷酸化发生在早期S期，并防止当NS 1诱导。NS 1对p14磷酸化的这种早期作用可能与细胞毒性直接相关，并且可能与先前报道的细胞DNA合成的抑制有关。在诱导期后期（24小时），NS 1还改变了50 kDa蛋白和35 kDa蛋白（分别为p50和p35）的合成。p35的微测序揭示了与β-微管蛋白的序列同源性。仅在NS 1敏感细胞系中观察到的NS 1的这些作用可能与蛋白质的细胞毒性有关。
Autonomous parvoviruses exert lytic and cytostatic effects believed to contribute to their antineoplastic activity. Studies with inducible clones have demonstrated a direct involvement of parvovirus nonstructural proteins (NS) in oncolysis. Human and rat fibroblasts have been stably transfected with MVM(p) (minute virus of mice prototype strain) NS genes cloned under the control of a hormone-inducible promoter. Dexamethasone-induced synthesis of the NS proteins in sensitive transformed cells results in cell killing within a few days. From these sensitive cell lines have been isolated some NS-resistant clones that also prove resistant to MVM(p) infection, suggesting that cell factors modulate NS cytotoxicity. We have previously reported that factors involved in cell cycle regulation may contribute to this modulation, since NS toxicity requires cell proliferation and correlates with a cell cycle perturbation leading to an arrest in phase S/G(2). In addition to its role in cytotoxicity, NS1 can regulate transcription driven by parvovirus and nonparvovirus promoters. Since phosphorylation is a critical event in controlling the activity of many proteins, notably transcription factors and cell cycle-regulated proteins, we have examined the effect of NS1 on the synthesis and phosphorylation of cell proteins. Our results indicate that NS1 interferes, within 7 h of induction, with phosphorylation of a protein of about 14 kDa (p14). Cell synchronization has enabled us to show that phosphorylation of this protein occurs in early S phase and is prevented when NS1 is induced. This early effect of NS1 on p14 phosphorylation may be directly linked to cytotoxicity and is probably related to the previously reported inhibition of cell DNA synthesis. Late in the induction period (24 h), NS1 also alters the synthesis of a 50-kDa protein and a 35-kDa protein (p50 and p35, respectively). Microsequencing of p35 reveals sequence homology with beta-tubulin. These effects of NS1, observed only in NS1-sensitive cell lines, may be related to the protein's cytotoxicity.