Entebbe bat virus

Entebbe Bat Virus is an enveloped virus, which means that it has to bind its envelope proteins to a cell surface protein on the cell that it's going to infect. In flavivirus virions, the fusion peptide is buried in dimmers of the fusion glycoprotein E. At low pH, the dimmers are disrupted, the proteins rotate to form trimers, and the fusion peptide is directed toward the cell membrane The viral envelope protein E attaches to host receptors, which mediates receptor-mediated endocytosis.. The viral nucleocapsid, as RNP, is released into the cytoplasm, where the RNA synthesis begins. The mechanism by which the contacts between the viral nucleocapsid and M protein, which forms a shell beneath the lipid bilayer, are broken to facilitate release of the nucleocapsid is not known (Flint).

Since Entebbe Bat Virus is in the family Flaviviridae, and has a (+) ssRNA genome, it must have the same replication process as those in the family of Flavivirdae. Entebbe Bat Virus replicates in the cytoplasm of the host cells. The genome is similar to host cellular mRNA except that the viral (+)ssRNA is missing the poly-A tail. Lacking a poly-A tail allows the virus to use cellular machinery to synthesize its genome and the proteins it needs Moreover, the genome encodes 3 structural proteins (Capsid, prM, and Envelope) and 8 non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5 and NS5B). The genomic RNA is modified at the 5′ end of positive-strand genomic RNA with a cap-1 structure.

Cellular RNA cap structures are formed with the action of an RNA triphosphatase, with guanylyltransferase, N7-methyltransferase and 2′-O methyltransferase. These are products of viral transcription. The NS3 protein encodes a RNA triphosphatase within its helicase domain. It uses the helicase ATP hydrolysis site to remove the γ-phosphate from the 5′ end of the RNA. The N-terminal domain of the NS5 is vital in producing mature RNA. RNA binding affinity is reduced by the presence of ATP or GTP and enhanced by S-adenosyl methionine (Henderson et al. 2011).

Once translated, the polyprotein is cleaved by a combination of viral and host proteases to release mature polypeptides. However, since cellular mRNAs need a poly-A tail to be considered mature. Therefore, the virus produces a polyprotein that is able to cut the translated viral polypeptide. The polyprotein contains an autocatalytic feature which automatically releases the first peptide, which is an enzyme. This enzyme is then able to cleave the remaining polyprotein. One of the products cleaved is a polymerase, responsible for the synthesis of a (-)ssRNA molecule. The newly produced (-)ssRNA will act as a template to construct (+)ssRNA, which will be the genome for the new virion particles (Flint).

Flavivirus genomic RNA replication occurs on rough endoplasmic reticulum membranes.

New viral particles are assembled. This occurs during the budding process which is important to produce the lipid envelope that will envelop that newly produced virion particle and cell lysis.