Capsid Proteins ; metabolism ; Endocytosis ; physiology ; Virus Internalization ; Viruses ; metabolism

Japanese encephalitis virus (JEV) is a pathogenic mosquito-borne flavivirus which is responsible for outbreaks of severe viral encephalitis. The cellular entry of JEV is a prerequisite for Japanese encephalitis, so the understanding of its underlying mechanisms will provide more approaches for treating such disease. In recent years, increasing research has been conducted to investigate the mechanisms of cellular entry of JEV, and the results of research on other flavivirus have expanded the research directions for JEV. More methods will be used to suppress JEV infection because of the development of E protein antibodies and the discovery of several inhibitors of the cellular entry process. This review will summarize the recent advances in the mechanisms of JEV cellular entry and membrane fusion.
Animals ; Biomedical Research ; trends ; Encephalitis Virus, Japanese ; genetics ; physiology ; Encephalitis, Japanese ; virology ; Humans ; Virus Internalization

Real-time quantitative PCR was used to characterize HearNPV DNA replication in exponential and stationary phases of HzAM1 cells. Results showed that the doubling time of HzAM1 cells was 22 h in exponential phases. Most of the exponential cells were in S phase (48.6%), and most of the stationary cells in G2/M phase (72.6%). The replication of viral DNA was completed within 60 h post infection (h p. i.) in different phases of HzAM1 cells. During 14 to 20 h p. i., the doubling time of HearNPV replica-tion was 1.8 h in exponential cells and 1.9 h in stationary cells, and no significant difference was found between them. But the amounts of BV entering and releasing, the final progeny virions and viral protein products in the infected exponential phase cells were obviously higher than that in the stationary phase cells. 25% of the total synthesized viral DNAs were released from infected exponential phase cells, but on-ly 13% from the infected stationary phase cells. Viral DNA started to be replicated from 7-8 h p. i. both in infected exponential phase and in stationary phase cells. But in infected exponential phase cells, BVs were started to release from 18-20 h p. i., and BVs were started to release from 22-25 h p. i. from infected sta-tionary phase cells. During 30-60 h p. i., the BV releasing rate was about 483 copies/cell/h in the expo-nential phase cells, but was 100 copies/cell/h in the stationary-phase cells. The initial viral DNA entering into exponential phase cells was much more than that entered into the stationary phase cells. The data of cell membrane fluidity at exponential and stationary phases suggested that the fluidity of cell membrane played an important role during virus entry.
Animals ; Cell Cycle ; Cell Line ; DNA Replication ; Membrane Fluidity ; Moths ; Nucleopolyhedrovirus ; physiology ; Virus Internalization ; Virus Replication

The respiratory syncytial virus (RSV) is one of the most common causes of acute infection of the lower respiratory tract among children. For viruses in the Paramyxoviridae subfamily, membrane fusion requires a specific interaction between two glycoproteins: the fusion protein and attachment protein. Membrane fusion of the RSV appears to be unique among paramyxoviruses in that fusion is accomplished by the fusion protein alone without help from the attachment protein. Here, we review recent achievements and advances in the study of membrane fusion triggered by the RSV published in high-impact-factor journals. We also review and make a comparative analysis of the popular hypotheses regarding membrane fusion of the RSV. Finally, we discuss the "hot topics" in current research and controversial data published in recent years in the hope of providing references for Chinese researchers.
Animals ; Humans ; Respiratory Syncytial Virus Infections ; virology ; Respiratory Syncytial Viruses ; genetics ; physiology ; Viral Fusion Proteins ; genetics ; metabolism ; Virus Internalization

OBJECTIVETo study the inhibitory activities of 3-trifluoromethyl benzamide derivatives against the entry of H5N1 influenza viruses.

METHODSThe lead compound was structurally modified to obtain 3 compounds with inhibitory activities against H5N1 influenza viruses. Specs compound librany was screened and 4 compounds were identified to have such inhibitory activities. The inhibitory activities of these compounds were tested at a celluar level against H5N1 influenza viruses.

RESULTS AND CONCLUSIONThe compounds 1a, 1b, 1e and 1f showed signifcant inhibitory activities against the entry of A/AnHui/1/2005 pseudovirus into the target cells with an IC50 value of 4.7 ± 0.3 µmol/L.

Antiviral Agents ; pharmacology ; Benzamides ; pharmacology ; Humans ; Influenza A Virus, H5N1 Subtype ; drug effects ; physiology ; Influenza, Human ; Virus Internalization ; drug effects

To determine the functions of N-carbohydrate chains in human parainfluenza virus type 3 hemagglutinin-neuraminidase(HN) protein, a PCR-based site-directed mutagenesis method was used to obtain N-glycan mutants. Protein electrophoresis rate, cell surface expression,receptor binding activity, neuraminidase activity and cell fusion promotion activity were determined. The HN proteins of single mutants (G1, G2, and G4) and multiple mutants (G12, G14, G24 and G124) migrated faster than the wild-type (wt) HN protein on polyacrylamide gels, while G3-mutated protein and wt HN protein migrated at the same position. There was no statistic difference in cell surface expression and neuraminidase activity between wt and each mutant HN protein (P>0.05), but receptor binding activity and cell fusion promotion activity of each mutant protein was reduced to significant extent (P<0.05). G1, G2 and G4 mutants exhibited re duced receptor binding activity, which was 83.94%, 76.45% and 55.32% of the wt level, respectively. G1, G2 and G4-mutated proteins also showed reductions in fusion promotion activity, which was 80.84%, 77.83% and 64.16%, respectively. Multiple mutants with G12-, G14-, G24- and G124- substitutions could further reduce receptor binding activities, 33.07%, 20.67%, 19.96% and 15.11% of the wt HN level, respectively. G12, G14, G24 and G124 mutants exhibited levels of fusion promotion activity that were only 46.360, 12.04%, 13.43% and 4.05% of the wt amount, respectively. As N-glycans of hPIV3 HN protein play an important role in receptor binding activity and cell fusion promotion activity of HN protein. We propose that the loss of N-glycans change the conformation or orientation of globular domain that is responsible for receptor binding and lower receptor binding activity and cell fusion promotion activi ty.
Glycosylation ; HN Protein ; chemistry ; genetics ; metabolism ; Humans ; Mutation ; Parainfluenza Virus 3, Human ; chemistry ; enzymology ; genetics ; physiology ; Protein Binding ; Receptors, Virus ; metabolism ; Respirovirus Infections ; metabolism ; virology ; Virus Internalization

Polytopic transmembrane protein, Niemann-Pick C1-Like 1 (NPC1L1) is localized at the apical membrane of enterocytes and the canalicular membrane of hepatocytes. It mediates intestinal cholesterol absorption and prevents extensive loss of cholesterol by transporting biliary cholesterol into hepatocytes. NPC1L1 is a molecular target of ezetimibe, an agent for hypercholesterolemia. Recently, NPC1L1 inhibition has been shown to prevent metabolic disorders such as fatty liver disease, obesity, diabetes, and atherosclerosis. In this review, the identification and characterization of NPC1L1, NPC1L1-dependent cholesterol transport, the relationship with pathogenesis of metabolic disease and its newly introduced function for virus entry are discussed.
Absorption ; Atherosclerosis ; Azetidines ; Cholesterol ; Enterocytes ; Fatty Liver ; Hepatocytes ; Hypercholesterolemia ; Intestines ; Membranes ; Metabolic Diseases ; Obesity ; Ezetimibe ; Virus Internalization

Middle East respiratory syndrome (MERS) has raised global public health concerns. The recent outbreak of MERS coronavirus (MERS-CoV) infection has led to 1 338 laboratory-confirmed cases in 26 countries worldwide as reported till 19 June, 2015. MERS-CoV may be considered a zoonotic virus that has crossed the species barrier to humans, but the pathogenesis and the routes of transmission are not completely understood. Most MERS-CoV cases reported thus far have a history of residence in or travel to the Middle East. Human-to-human transmission though was observed on some occasions in Korea, it is documented as non-sustainable event. The envelope spike glycoprotein on the surface of MERS-CoV which mediates receptor binding, membrane fusion and viral entry is thought to be involved in the mechanism of MERS-CoV.No specific and effective treatment for MERS-CoV is currently recommended, although supportive treatment has played an important role. Prophylactic strategies are necessary to prevent MERS-CoV infection.
Coronavirus Infections ; diagnosis ; epidemiology ; therapy ; Humans ; Middle East Respiratory Syndrome Coronavirus ; pathogenicity ; physiology ; Spike Glycoprotein, Coronavirus ; metabolism ; Virus Internalization

The research on intracellular trafficking of adenovirus has been described mainly through observations of subgroup C adenoviruses in transformed cell lines. The basic elements of the trafficking pathway include binding to receptors at the cell surface, internalization by endocytosis, lysis of the endosomal membrane, escape to the cytosol, intracellular trafficking along microtubules, nuclear pore docking, and viral genome translocation into the nucleus. More than 80% of the adenovirus genome is delivered to the nucleus in a highly efficient manner in approximately 1 h. However, exceptions to this trafficking pattern have been noted, including: variations based on target cell type, cell physiology, and adenovirus serotype. This review summarizes mechanism of adenovirus infection pathway and intracellular trafficking, providinging a foundation for the development of clinical adenoviral vector.
Adenoviridae ; physiology ; Cell Membrane ; virology ; Cell Nucleus ; virology ; Cytoplasm ; virology ; Endocytosis ; Endosomes ; virology ; Genetic Vectors ; Humans ; Microtubules ; Virus Internalization

Hepatitis c virus (HCV) infection has become one of the global public health problem,while there is no vaccine to prevent HCV infection, the so-called "cocktail" therapy that use a combination of drugs targeting multiple steps in the HCV infection cycle could achieve better curative effect. the process of HCV entering into host cell is the important step of drug intervention, in which HCV envelope protein El and E2, Host cell factors including Heparan sulfate(HS), CD81, scavenger receptor class B type I (SR-BI), Occludin (OCLD), Claudin (CLDN), low densitity lipoprotein receptor (LDLR), dendritic cell-specific ICAM-3-grabbing nonintegrin (DC-SIGN), Liver/lymph node specific ICAM-3-grabbing integrin(L-SIGN), trans- ferrin receptor 1 (TfR1) and so on play a important role. The virus and the host factors can be used as targets of hcv entry inhibitors many studies have shown that as novel and promising compounds, HCV entry inhibitors combinating with other drugs can be more effective in the treatment of HCV, this paper have re- viewed targets and inhibitors of HCV enterring into host cell since 1990s.
Animals ; Antiviral Agents ; pharmacology ; Hepacivirus ; drug effects ; physiology ; Hepatitis C ; genetics ; metabolism ; virology ; Humans ; Receptors, Virus ; genetics ; metabolism ; Viral Envelope Proteins ; genetics ; metabolism ; Virus Internalization ; drug effects