Vaccinia virus nucleoside triphosphate phosphohydrolase I controls early and late gene expression by regulating the rate of transcription.
Vaccinia virus nucleoside triphosphate phosphohydrolase I controls early and late gene expression by regulating the rate of transcription.
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痘苗病毒核苷三磷酸磷酸水解酶 I 通过调节转录速率来控制早期和晚期基因表达。
DOI：
10.1128/jvi.67.12.7561-7572.1993
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发表时间：
1993
影响因子：
5.4
通讯作者：
Esteban,M
中科院分区：
文献类型：
--
作者：
Diaz-Guerra,M;Esteban,M
我们对感染温度敏感痘苗病毒突变体 (ts36) 的培养细胞中产生的病毒 mRNA 和蛋白质进行了详细分析，该突变体含有修饰的核苷三磷酸磷酸水解酶 I (NPH-I)（一种核酸依赖性 ATP 酶）。使用表达荧光素酶标记的重组病毒 (ts36LUC)，我们在七种不同的细胞系中发现，在不允许的温度下，受体基因的早期表达受到强烈抑制（73.8% 至 98.7%）。不同早期病毒多肽的稳态水平也严重降低。对两个早期基因（DNA 聚合酶和 D5）的稳态 mRNA 水平的分析表明，早期多肽合成的抑制与非允许温度下积累的 mRNA 水平的降低相关。对晚期病毒多肽和mRNA稳态水平的分析表明，NPH-I对中间和晚期基因表达的调节是直接的，而不仅仅是其抑制早期基因表达作用的结果。对获救病毒 (R36) 的表征表明，ts36 的温度敏感表型仅归因于 NPH-I 基因中的点突变。突变表型并不是由于 ts36 病毒粒子中存在的 NPH-I 水平降低或由于在不允许的温度下感染的细胞中该酶的稳定性差异所致，而是由于该蛋白质的正常酶活性受到抑制。对透化纯化病毒颗粒中病毒转录活性的测量表明，痘苗病毒的正常转录速率需要 NPH-I。我们的研究结果表明 ts36 是痘苗病毒的一个严重缺陷的早期突变体，并证明 NPH-I 在控制早期和晚期病毒基因表达中发挥着关键作用，可能是通过在病毒生长周期中调节 mRNA 转录的辅助功能。
We have carried out a detailed analysis of viral mRNAs and proteins produced in cultured cells infected with a temperature-sensitive vaccinia virus mutant (ts36) containing a modified nucleoside triphosphate phosphohydrolase I (NPH-I), a nucleic acid-dependent ATPase. Using a recombinant virus (ts36LUC) which expresses the luciferase marker, we showed in seven different cell lines that early expression of the receptor gene is strongly inhibited (73.8 to 98.7%) at the nonpermissive temperature. The steady-state levels of different early viral polypeptides were also severely reduced. Analysis of steady-state mRNA levels for two early genes (DNA polymerase and D5) showed that inhibition of early polypeptide synthesis correlated with a reduction in the levels of mRNA accumulated at the nonpermissive temperature. Analysis of steady-state levels of late viral polypeptides and of mRNAs indicated that NPH-I regulation of intermediate and late gene expression is direct and not simply a consequence of its role in inhibiting early gene expression. Characterization of a rescued virus (R36) demonstrated that the temperature-sensitive phenotype of ts36 is due solely to the point mutation in the NPH-I gene. The mutant phenotype is not due to reduced levels of NPH-I present in ts36 virions or to the differential stability of this enzyme in cells infected at the nonpermissive temperature but to inhibition of normal enzymatic activity for this protein. Measurement of viral transcriptional activity in permeabilized purified virions demonstrated that NPH-I is required for normal rates of transcription in vaccinia virus. Our findings show ts36 to be a strongly defective early mutant of vaccinia virus and prove that NPH-I plays a key role in the control of early and late virus gene expression, possibly by way of an auxiliary function which regulates mRNA transcription during the virus growth cycle.