Question

1a. Describe the steps of how the pathogen (the Powassan virus) reproduce virons.

1b. What would be different if it were negative sense?

*Please answer and explain both parts of the question!! but more importantly part b!!!*

Answer 1

Answer 1a: The flavivirus (Powassan virus) contains positive sense RNA strand. It is harbored by the ticks and cause infection in the humans. The replication events of this virus inside the host are as follows:

Attachment: The virus get attached to cell surface of the host. The components helps in attachments are heparan sulfate, 3-grabbing nonintegrin (DC-SIGN), laminin binding protein.

Entry to the cytoplasm: The viral partical vesicle and endosome of the the host cell fuses, the enzymes degrade the nucleocapsid and positive strand RNA is enterd to the host cytoplasm.

Replication and assembly: Viral RNA core form messenger RNA by using itself as a template. then viral proteins are translated from it as a single large polyprotein chain in ribosomes on Endoplasmic reticulam membrane (cytoplasmic surface). two types of proteins (nonstructural and structural) are generated and get accumulated on cytoplasmic and lumen of Endoplasmic reticulam. The replication complex is protected in the host by a membrane bound system and the ssRNA is replicated to dsRNA. Then nascent RNA is packed under structural proteins (C, prM, and E). The virus get matured inside the host using secretory pathway of Golgi complexes.

Egress: Then the matured particles gets released from the host cell by exocytosis and infects new cells.

Answer 1b: If the viral RNA is the negative sense the replication mechanism will be different from the positive RNA strand of the virus. When positive sense RNA is enterd to the host cell, the RNA is directly utilize host cell machinery such as ribosomes for preparing proteins. But when negative sense RNA enters in to the host cell it directly can not use host cell machinery for preparing proteins. They first transcribe viral polymerases to form the complementary copy of the negative sense RNA. This complementary copy is Positive strand RNA, which then act as a template and use protein synthetic machinery of the host.

positive-sense can be directly accessed by host ribosomes to immediately form proteins