Processing of nonstructural proteins NS4A and NS4B of dengue 2 virus in vitro and in vivo.
Processing of nonstructural proteins NS4A and NS4B of dengue 2 virus in vitro and in vivo.
复制标题
登革热 2 病毒非结构蛋白 NS4A 和 NS4B 的体外和体内加工。
DOI：
10.1016/0042-6822(91)90540-r
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发表时间：
1991
期刊：
影响因子：
3.7
通讯作者：
Strauss,JH
中科院分区：
文献类型：
--
作者：
Preugschat,F;Strauss,JH
分析了登革2型病毒的两种疏水性非结构蛋白NS4A和NS4B在无细胞系统和感染细胞中的产生。在DEN2感染的细胞中，NS4B首先被产生为表观大小为30 kDa的多肽；然后NS4B被翻译后修饰，以一种未知的方式产生表观大小为28 kDa的多肽。NS4B修饰的速度和程度与细胞有关；在BHK细胞中，30 kDa形式转化为28 kDa形式的半衰期为90分钟。NS4B的N端序列分析表明，N端是由一种具有与信号酶相似的特异性的酶产生的。在感染DEN2的哺乳动物细胞中也发现了低水平的可能的多聚蛋白NS4AB，但在蚊子细胞中没有发现，这表明一小部分DEN4A/4B的裂解可能发生在翻译后，或者一些非结构性多蛋白逃脱了正常的加工。除了在NS4A和NS4B中表达的序列外，感染细胞中4A/4B键的切割还需要DEN2序列的表达，因为牛痘表达系统在细胞中产生的NS4AB没有被切割。由痘苗病毒表达系统在细胞中产生的NS4AB在翻译后被修饰，推测方式与NS4B相同。我们发现，在无细胞系统中翻译DEN2多聚蛋白时，NS4A的N端是由病毒非结构蛋白酶NS3切割产生的，并且DEN2多蛋白的加工是以首选的但非强制性的顺序进行的。
The production, from polyprotein precursors, of two hydrophobic nonstructural proteins of dengue 2 (DEN2) virus, NS4A and NS4B, was analyzed both in cell-free systems and in infected cells. In DEN2-infected cells, NS4B is first produced as a peptide of apparent size 30 kDa; NS4B is then post-translationally modified, in an unknown way, to produce a polypeptide of apparent size 28 kDa. The rate and extent of NS4B modification was found to be cell-dependent; in BHK cells the half-time for the conversion of the 30-kDa form to the 28-kDa form was 90 min. N-terminal sequence analysis of NS4B suggests that the N-terminus is produced by an enzyme with a specificity similar to that of signalase. Low levels of a putative polyprotein, NS4AB, were also found in mammalian cells, but not mosquito cells, infected with DEN2, suggesting that a small proportion of DEN2 4A/4B cleavage can occur post-translationally or that some nonstructural polyproteins escape normal processing. Cleavage of the 4A/4B bond in infected cells required expression of DEN2 sequences in addition to those in NS4A and NS4B, as NS4AB produced in cells by a vaccinia expression system was not cleaved. NS4AB produced in cells by a vaccinia expression system was modified post-translationally, presumably in the same way as NS4B. We show that upon translation of DEN2 polyproteins in a cell-free system, the N-terminus of NS4A is generated by cleavage by the viral nonstructural proteinase NS3 and that processing of DEN2 polyproteins occurs with a preferred, but nonobligatory order.