Dengue virus structural differences that correlate with pathogenesis
Dengue virus structural differences that correlate with pathogenesis
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DOI：
10.1128/jvi.73.6.4738-4747.1999
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发表时间：
1999-06-01
影响因子：
5.4
通讯作者：
Rico-Hesse, R
中科院分区：
文献类型：
--
作者：
Leitmeyer, KC;Vaughn, DW;Rico-Hesse, R
由于缺乏体外和体内的疾病模型，对登革热病毒发病机制的了解一直受到阻碍。对导致严重登革热、登革出血热(DHF)和更常见的登革热(DF)的病毒因素的研究仅限于间接的临床和流行病学联系。为了识别DHF的病毒决定因素，我们开发了一种直接从患者血浆中比较登革2型基因组(逆转录酶聚合酶链式反应有六个片段)的方法。用于比较的样本选自之前描述的两种登革热2型基因，这两种基因已被证明是引起DF或DHF的原因；对11株登革热病毒的全基因组序列进行分析后，发现仅与登革热相关的登革热病毒与可能引起登革出血热的登革热病毒存在几个结构上的差异：Prm、E、NS、Lb和NS5基因共有6个编码氨基酸的电荷差异，而5‘非翻译区(NTR)和3’NTR区的序列差异被预测会改变RNA的二级结构。我们推测，DHF的主要决定因素位于(I)E蛋白的390氨基酸，据称它改变了病毒与宿主细胞的结合；(Ii)在5‘NTR的下游环(68到80核苷酸)，可能参与翻译启动；以及(Iii)在3’NTR的上游300核苷酸，它可能通过形成复制中间产物来调节病毒的复制。目前尚不清楚非结构蛋白NS4B和NS5的四个氨基酸差异的意义，NS4B和NS5分别是一种假定的运输蛋白和病毒RNA聚合酶。这种研究登革热病毒基因组差异的新方法应该更好地反映自然宿主中病毒RNA群体的真实组成，并允许它们与发病机制相关联。
The understanding of dengue virus pathogenesis has been hampered by the lack of in vitro and in vivo models of disease. The study of viral factors involved in the production of severe dengue, dengue hemorrhagic fever (DHF), versus the more common dengue fever (DF), have been limited to indirect clinical and epidemiologic associations. In an effort to identify viral determinants of DHF, we have developed a method for comparing dengue type 2 genomes (reverse transcriptase PCR in six fragments) directly from patient plasma. Samples for comparison were selected from two previously described dengue type 2 genotypes which had been shown to be the cause of DF or DHF;. When full genome sequences of 11 dengue viruses were analyzed, several structural differences were seen consistently between those associated with DF only and those with the potential to cause DHF: a total of six encoded amino acid charge differences were seen in the prM, E, NS lb, and NS5 genes, while sequence differences observed within the 5' nontranslated region (NTR) and 3' NTR were predicted to change RNA secondary structures. We hypothesize that the primary determinants of DHF reside in (i) amino acid 390 of the E protein, which purportedly alters virion binding to host cells; (ii) in the downstream loop (nucleotides 68 to 80) of the 5' NTR,which may be involved in translation initiation; and (iii) in the upstream 300 nucleotides of the 3' NTR, which may regulate viral replication via the formation of replicative intermediates. The significance of four amino acid differences in the nonstructural proteins NS4b and NS5, a presumed transport protein and the viral RNA polymerase, respectively, remains unknown. This new approach to the study of dengue virus genome differences should better reflect the true composition of viral RNA populations in the natural host and permit their association with pathogenesis.