Question

Compare and contrast two different forms of viral internalization—influenza and HIV. Briefly compare viral proteins involved, host receptors, and pH dependence of internalization.

PLEASE DISCUSS ALL PARTS. Thank you!

Answer 1

1. The influenza virus has two receptors hemagglutinin (HA) and neuraminidase (NA) in the viral coat.

2. HA interacts with the sialic acids present on the surface of the host cell membrane.

3. Interaction of HA with sialic acids leads to the internalization of the virus and forms early endosomes. pH of the early endosome is not acidic.

4. Conversion of the early endosome to late endosome causes a drop of pH which causes the release of viral genetic material into the cytoplasm.

1 and 2. HIV virus has two receptors gp 41 and gp 120. Interaction of gp120 with the CD4 receptors in the presence of coreceptor (CCR5 or CXCR4) of host cell causes internalization of the virus.

3 and 4. Internalization leads to the release of genetic material (preintegration complex) in the host cell cytosol. HIV has RNA as genetic material. The presence of reverse transcriptase in the viruses synthesizes DNA from RNA. This newly synthesized DNA interact with the integrase protein (a component of the preinitiation complex) and enters the nucleus.

5 and 6. Viral DNA integrated into the host genome and synthesized its own coat proteins.

7. synthesis of all viral components after integration assemble vial particle to release.