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Title: Luteolin escape mutants of dengue virus map to prM and NS2B and reveal viral plasticity during maturation
Authors: Vasudevan, Subhash G.
Peng, Minhua
Swarbrick, Crystall Marie Dawn
Chan, Kitti Wing-Ki
Luo, Dahai
Zhang, Wei
Lai, Xiaoping
Li, Geng
Keywords: DRNTU::Science::Medicine
Dengue Virus
Issue Date: 2018
Source: Peng, M., Swarbrick, C. M. D., Chan, K. W.-K., Luo, D., Zhang, W., Lai, X., . . . Vasudevan, S. G. (2018). Luteolin escape mutants of dengue virus map to prM and NS2B and reveal viral plasticity during maturation. Antiviral Research, 154, 87-96. doi:10.1016/j.antiviral.2018.04.013
Series/Report no.: Antiviral Research
Abstract: We previously showed that luteolin, a well-known plant-derived component found in the “heat clearing” class of Traditional Chinese Medicine (TCM) herbs, is an uncompetitive inhibitor (Ki 58.6 μM) of the host proprotein convertase furin, an endoprotease that is required for maturation of flaviviruses in the trans-Golgi compartment. Luteolin also weakly inhibited recombinant dengue virus NS2B/NS3 protease (Ki 140.36 μM) non-competitively. In order to further explore the mechanism of inhibition we isolated resistant mutants by continuous passaging of DENV2 in the presence of increasing concentrations of luteolin. Nucleotide sequence analysis of the luteolin-resistant escape mutants revealed nucleotide changes that lead to amino acid substitutions in the prM (T79R) and NS2B (I114M) genes. These mutations were introduced into a DENV2 infectious clone and tested for replication in Huh-7 cells. Interestingly we found that the replication kinetics of prM T19R-NS2B I114M double-mutant (DM) was similar to wild-type virus (WT). On the other hand the prM T79R single mutant (SM1) was attenuated and the NS2B I114M single mutant (SM2) showed enhanced replication. Time of drug addition assay with luteolin showed that the mutant viruses were able to produce more mature virions than WT in the order DM > SM2>SM1>WT. Exogenous addition of furin to purified immature WT or mutant viruses revealed that luteolin blocked the prM cleavage of WT and SM2 at a similar level. On the other hand the SM1 immature virus showed some cleavage while the DM immature virus revealed efficient furin cleavage of prM even in the presence of 50 μM luteolin. Our findings suggest that luteolin inhibition of furin may occur at host/pathogen interface that permits the virus to escape the suppression by mutating key residue that may lead to an altered interface.
ISSN: 0166-3542
DOI: 10.1016/j.antiviral.2018.04.013
Rights: © 2018 Elsevier B.V. All rights reserved. This paper was published in Antiviral Research and is made available with permission of Elsevier B.V.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:LKCMedicine Journal Articles

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