VPg protein, the enzyme can go back and forth making new copies of genome which is why you get a high production of virus particles because it is made very quickly-helps the virus spread quickly Dengue virus Targets immune cells
Cell surface receptors Cognate receptor-normal infection o Receptor mediated endocytosis o Virus is enclosed in endosome o pH lowers and virus capsid is released into cytoplasm due to conformational change in the surface proteins which form spike like structures o The viral RNA travels to rough ER where it can be directly translated into proteins o The whole viral genome is translated as a single long polyprotein chain o Protease enzyme activates all other proteins in the polyprotein chains Fc receptor- antibody dependent enhancement o Antibodies prevent subsequent disease for most pathogens o When a person is infected, B cells begin to generate antibodies against the infection. The antibodies bind to virus to clear the virus. o Usually, this helps develop immunity to this particular strand of infection. However, with dengue, the antibodies can actually make subsequent infections worse. o A person re-infected with the same strain of dengue, the immune response would work normally but if infected with a new strain (most likely since dengue mutates rapidly), the antibodies will be able to bind to the new strain but they are not able to neutralize the infection. Instead, they give the virus the ability to bind to the Fc receptor on the cell surface. Now this virus can bind its normal cognate receptor and the Fc receptor. o This results in an increased number of infected cells and a suppression of the antiviral immune response. Since the antibody response is suboptimal, this could result in a greater increase in viral production and a more severe infection. Secondary dengue infections are more lethal than primary infections. Structural anchor on the inner and outer surfaces of ER o Virus on the lumen side of the ER releases its genome into the cytoplasm which gets translated into proteins which form a replication complex which anchor on the lumen side or cytoplasmic side of ER Viral RNA is synthesized in many steps o The ends fold up and the RNA forms a circle o It then attaches to the replication complex o A negative sense copy is made o The pair of RNA strands forms a double helix o It then becomes a circle again and the negative strand is used as a template for a new positive strand o Many copies of the positive strand are made by repeated cycles o Some are translated to make more viral proteins and new viruses o The envelope proteins aggregate in the lumen of the ER and Capsid proteins aggregate in the cytoplasmic side
o A viral RNA binds to capsid protein and is packaged into a new particle as it buds off into the ER o The virus is still immature, its pre-membrane proteins cover tips of envelope proteins to prevent premature fusion back into cell o The virus buds off and travels through the Golgi complex toward the cell surface o
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