UNLABELLED Flavivirus replication is mediated by a membrane-associated replication complex where viral membrane proteins NS2A, NS2B, NS4A, and NS4B serve as the scaffold for the replication complex formation. Here, we used dengue virus serotype 2 (DENV-2) as a model to characterize viral NS4A-NS4B interaction. NS4A interacts with NS4B in virus-infected cells and in cells transiently expressing ...

UNLABELLED Flavivirus replication is mediated by a complex machinery that consists of viral enzymes, nonenzymatic viral proteins, and host factors. Many of the nonenzymatic viral proteins, such as NS4B, are associated with the endoplasmic reticulum membrane. How these membrane proteins function in viral replication is poorly understood. Here we report a robust method to express and purify dengu...

Hepatitis C virus (HCV) belongs to the Hepacivirus genus in the Flaviviridae family. Among the least known viral proteins in this family is the nonstructural protein NS4B, which has been suggested to be a part of the replication complex. Hydrophobicity plots indicate a common profile among the NS4B proteins from different members of the Flaviviridae family, suggesting a common function. In orde...

PTC725 is a small molecule NS4B-targeting inhibitor of hepatitis C virus (HCV) genotype (gt) 1 RNA replication that lacks activity against HCV gt2. We analyzed the Los Alamos HCV sequence database to predict susceptible/resistant HCV gt's according to the prevalence of known resistance-conferring amino acids in the NS4B protein. Our analysis predicted that HCV gt3 would be highly susceptible to...

In the Huh-7.5 hepatoma cell line, replication of the genotype 1a H77 strain of hepatitis C virus (HCV) is attenuated compared to that of the genotype 1b Con1 strain. This study identifies the poorly characterized integral membrane protein, NS4B, as a major determinant for this replication difference. Chimeric H77 subgenomic replicons containing the entire NS4B gene from Con1 in place of the H7...

Classical swine fever virus (CSFV) is a fatal pig pestivirus and causes serious financial losses to the pig industry. CSFV NS4B protein is one of the most important viral replicase proteins. Rab5, a member of the small Rab GTPase family, is involved in infection and replication of numerous viruses including hepatitis C virus and dengue virus. Until now, the effects of Rab5 on the proliferation ...

Among the least-known hepatitis C virus proteins is the non-structural protein 4B (NS4B). It localizes to the endoplasmic reticulum (ER) membrane and induces membrane changes, resulting in a membranous web that is reported to be the locale for virus replication. A model was presented previously for the topology of recombinant HCV NS4B of the 1a genotype based on in vitro data. In this model, th...

Studies of the hepatitis C virus (HCV) life cycle have been aided by development of in vitro systems that enable replication of viral RNA and production of infectious virus. However, the functions of the individual proteins, especially those engaged in RNA replication, remain poorly understood. It is considered that NS4B, one of the replicase components, creates sites for genome synthesis, whic...

background: detection of hepatitis c virus specific antibodies is the initial step in chronic hcv diagnosis.  hcv ns4b is among the most immunogenic hcv antigens and has been widely used in commercial enzyme immunoassays (eia). additionally, ns4b, a key protein in the virus replication, can be an alternative target for antiviral therapy.objectives: development of a new method for high-level exp...

During infection, hepatitis C virus (HCV) NS4B protein remodels host membranes to form HCV replication complexes (RC) which appear as foci under fluorescence microscopy (FM). To understand the role of Rab proteins in forming NS4B foci, cells expressing the HCV replicon were examined biochemically and via FM. First, we show that an isolated NS4B-bound subcellular fraction is competent for HCV RN...