Shope fibroma virus. II. Role of the virion-associated nucleases.
Shope fibroma virus. II. Role of the virion-associated nucleases.
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肖普纤维瘤病毒。
DOI：
10.1128/jvi.41.1.104-109.1982
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发表时间：
1982
影响因子：
5.4
通讯作者：
Freimuth,P
中科院分区：
文献类型：
--
作者：
Pogo,BG;Stein,A;Freimuth,P
研究了Shope纤维瘤病毒（SFV）感染对宿主DNA合成的影响。杀细胞株，SFV-I，感染后不久（2小时），抑制掺入[3 H]胸苷到核DNA，而非杀细胞株，SFV-W，这样做后（10小时感染后），并在较小程度上。此外，在SFV-W感染的细胞中，在感染后3至4小时记录到宿主DNA合成的两至三倍刺激。由于病毒体相关核酸酶与宿主合成的关闭有关，因此在纯化的病毒体制剂中测量了这些和其他酶活性。SFV毒株和牛痘病毒含有等量的DNA依赖性RNA聚合酶、ATP酶和蛋白激酶活性。然而，在SFV-W中，pH4.5的核酸外切酶活性低于SFV-I和牛痘病毒，并且几乎检测不到pH7.8的核酸内切酶水平。为了测试核酸内切活性的缺乏是否对病毒穿透后发生的亲本DNA中的交联的去除具有一些影响，跟踪病毒粒子SFV DNA的命运。大部分（80%）的SFV-I和SFV-W的DNA分子提取后，病毒吸附沉淀在碱性蔗糖梯度交联。在感染3小时后，75%的SFV-I DNA分子缺乏交联，而78%的SFV-W DNA仍然保持交联。当在限制性片段中测试交联的存在时，获得了相同的结果。两者合计，这些结果表明，病毒体相关的核酸酶参与宿主DNA合成的早期关闭和从亲本病毒DNA中消除交联。
The effect of Shope fibroma virus (SFV) infection on host DNA synthesis was investigated. The cytocidal strain, SFV-I, inhibited the incorporation of [3H]thymidine into nuclear DNA very shortly (2 h) after infection, whereas the noncytocidal strain, SFV-W, did so later (10 h postinfection) and to a lesser extent. Furthermore, a two- to threefold stimulation of host DNA synthesis was recorded in SFV-W-infected cells 3 to 4 h after infection. Since virion-associated nucleases have been implicated in the shutoff of host synthesis, these and other enzymatic activities were measured in purified virion preparations. The SFV strains and vaccinia virus contained equivalent amounts of DNA-dependent RNA polymerase, ATPase, and protein kinase activities. However, in SFV-W the pH 4.5 exonuclease activity was lower than in SFV-I and vaccinia virus, and the level of pH 7.8 endonuclease was almost undetectable. To test whether the lack of endonucleolytic activity had some effect on the removal of the cross-links in the parental DNA that occurs after viral penetration, the fate of the virion SFV DNA was followed. The majority (80%) of the SFV-I and SFV-W DNA molecules extracted after viral adsorption sedimented in alkaline sucrose gradients as cross-linked. After 3 h of infection, 75% of the SFV-I DNA molecules lacked cross-links, whereas 78% of the SFV-W DNA still remained cross-linked. The same results were obtained when the presence of cross-links was tested in restriction fragments. Taken together, these results indicate that virion-associated nucleases are involved in the early shutoff of host DNA synthesis and in the elimination of cross-links from the parental viral DNA.