Topic
NS5B
About: NS5B is a research topic. Over the lifetime, 1314 publications have been published within this topic receiving 59534 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: It is concluded that the defect in replication fitness is not due to defective polymerase or replicase function and is more likely to result from the inability of the mutated NS5B to optimally regulate Rb abundance and thereby modulate host gene expression.
Abstract: Hepatitis C virus (HCV) downregulates the retinoblastoma tumor suppressor protein (Rb), a central cell cycle regulator which is also targeted by oncoproteins expressed by DNA tumor viruses. HCV genome replication is also enhanced in proliferating cells. Thus, it is possible that HCV interactions with host cell cycle regulators, such as Rb, have evolved to modify the intracellular environment to promote viral replication. To test this hypothesis and to determine the impact of viral regulation of Rb on HCV replication, we constructed infectious viral genomes containing mutations in the Rb-binding motif of NS5B which ablate the ability of HCV to regulate Rb. These genomes underwent replication in transfected cells but produced variably reduced virus yields. One mutant, L314A, was severely compromised for replication and rapidly mutated to L314V, thereby restoring both Rb regulation and replication competence. Another mutant, C316A, also failed to downregulate Rb abundance and produced virus yields that were about one-third that of virus with the wild-type (wt) NS5B sequence. Despite this loss of replication competence, purified NS5B-C316A protein was two- to threefold more active than wt NS5B in cell-free polymerase and replicase assays. Although small interfering RNA knockdown of Rb did not rescue the replication fitness of these mutants, we conclude that the defect in replication fitness is not due to defective polymerase or replicase function and is more likely to result from the inability of the mutated NS5B to optimally regulate Rb abundance and thereby modulate host gene expression.
26 citations
TL;DR: This work is the first example of both inactive uridine and cytidine analogues of a nucleoside being converted to active anti-HCV nucleosides via 5′-monophosphate prodrugs.
Abstract: Background:2′-C-methyl and 4′-azido nucleosides have previously demonstrated inhibition of hepatitis C virus (HCV) replication by targeting the RNA-dependent RNA polymerase NS5B In an effort to di
26 citations
TL;DR: Aryl dihydrouracil derivatives were identified from high throughput screening as potent inhibitors of HCV NS5B polymerase as discussed by the authors, and they were shown to be non-competitive with respect to template RNA and elongation nucleotide substrates.
25 citations
TL;DR: It is suggested that V AP-C acts as a negative regulator of HCV propagation and that the expression of VAP-C may participate in the determination of tissue tropism ofHCV propagation.
Abstract: Human vesicle-associated membrane protein-associated protein (VAP) subtype A (VAP-A) and subtype B (VAP-B) are involved in the regulation of membrane trafficking, lipid transport and metabolism, and the unfolded protein response. VAP-A and VAP-B consist of the major sperm protein (MSP) domain, the coiled-coil motif, and the C-terminal transmembrane anchor and form homo- and heterodimers through the transmembrane domain. VAP-A and VAP-B interact with NS5B and NS5A of hepatitis C virus (HCV) through the MSP domain and the coiled-coil motif, respectively, and participate in the replication of HCV. VAP-C is a splicing variant of VAP-B consisting of the N-terminal half of the MSP domain of VAP-B followed by the subtype-specific frameshift sequences, and its biological function has not been well characterized. In this study, we have examined the biological functions of VAP-C in the propagation of HCV. VAP-C interacted with NS5B but not with VAP-A, VAP-B, or NS5A in immunoprecipitation analyses, and the expression of VAP-C inhibited the interaction of NS5B with VAP-A or VAP-B. Overexpression of VAP-C impaired the RNA replication of the HCV replicon and the propagation of the HCV JFH1 strain, whereas overexpression of VAP-A and VAP-B enhanced the replication. Furthermore, the expression of VAP-C was observed in various tissues, whereas it was barely detected in the liver. These results suggest that VAP-C acts as a negative regulator of HCV propagation and that the expression of VAP-C may participate in the determination of tissue tropism of HCV propagation.
25 citations
TL;DR: The crystal structure of an analogue was solved and provided rationalization of the SAR of this series of non-nucleoside inhibitors targeting the HCV polymerase, which binds in a distinct manner in the palm domain of NS5B consistent with biochemical analysis using enzyme mutant variants.
25 citations