Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen 40002, Thailand.
Viruses. 2023 Apr 17;15(4):982. doi: 10.3390/v15040982.
Dengue virus (DENV) is an arbovirus whose transmission cycle involves disparate hosts: humans and mosquitoes. The error-prone nature of viral RNA replication drives the high mutation rates, and the consequently high genetic diversity affects viral fitness over this transmission cycle. A few studies have been performed to investigate the intrahost genetic diversity between hosts, although their mosquito infections were performed artificially in the laboratory setting. Here, we performed whole-genome deep sequencing of DENV-1 ( = 11) and DENV-4 ( = 13) derived from clinical samples and field-caught mosquitoes from the houses of naturally infected patients, in order to analyze the intrahost genetic diversity of DENV between host types. Prominent differences in DENV intrahost diversity were observed in the viral population structure between DENV-1 and DENV-4, which appear to be associated with differing selection pressures. Interestingly, three single amino acid substitutions in the NS2A (K81R), NS3 (K107R), and NS5 (I563V) proteins in DENV-4 appear to be specifically acquired during infection in mosquitoes. Our study shows that the NS2A (K81R) mutant replicates similarly to the wild-type infectious clone-derived virus, while the NS3 (K107R), and NS5 (I563V) mutants have prolonged replication kinetics in the early phase in both Vero and C6/36 cells. These findings suggest that DENV is subjected to selection pressure in both mosquito and human hosts. The NS3 and NS5 genes may be specific targets of diversifying selection that play essential roles in early processing, RNA replication, and infectious particle production, and they are potentially adaptive at the population level during host switching.
登革病毒（DENV）是一种黄病毒，其传播周期涉及不同的宿主：人类和蚊子。病毒 RNA 复制的易错性质导致了高突变率，而高遗传多样性则影响了该传播周期中的病毒适应性。已经有一些研究旨在调查宿主间的病毒内遗传多样性，尽管它们的蚊子感染是在实验室环境中人为进行的。在这里，我们对从临床样本和从自然感染患者家中捕获的蚊子中分离得到的 DENV-1（n=11）和 DENV-4（n=13）进行了全基因组深度测序，以分析 DENV 宿主间的病毒内遗传多样性。在 DENV-1 和 DENV-4 的病毒群体结构中观察到了明显的 DENV 内遗传多样性差异，这似乎与不同的选择压力有关。有趣的是，在 DENV-4 中，NS2A（K81R）、NS3（K107R）和 NS5（I563V）蛋白中的三个单一氨基酸取代似乎是在蚊子感染过程中特异性获得的。我们的研究表明，NS2A（K81R）突变体的复制与野生型感染性克隆衍生病毒相似，而 NS3（K107R）和 NS5（I563V）突变体在 Vero 和 C6/36 细胞中的早期复制动力学延长。这些发现表明，DENV 在蚊子和人类宿主中都受到选择压力的影响。NS3 和 NS5 基因可能是多样化选择的特定靶点，在早期加工、RNA 复制和感染性颗粒产生中发挥着重要作用，并且在宿主转换过程中可能在种群水平上具有适应性。
