Lecture 41 - Virology Budding & Release Flashcards
what 3 things interact to create a virion
- viral nucleic acid
- viral proteins
- host proteins
summarize virion assembly in 6 steps
- formation of structural units from viral protein
- assembly of protein shell
- selective packaging of nucleic acid and essential virion components
- acquisition of glycoprotein
- release from host cell
- maturation into infectious virus particles
what two steps of assembly are not common to all viruses
acquisition of envelope and maturation
T/F: assembly is dependent on host cell machinery
TRUE
what are examples of host cell machinery
- cellular chaperones
- nuclear import and export machinery
- secretory pathway
- transport systems
what are the mechanisms for viral release
- cytolysis
- budding
- multinucleate syncytia
- formation of cell-to-cell bridges
- non-lytic release in vesicles
describe cytolysis
cell dies and the virus is released
what is the difference between necrosis and apoptosis
necrosis is not programmed whereas apoptosis is
describe budding
nucleocapsid acquires an envelope by budding through the cell membrane (picks up new proteins)
T/F: budding is not restricted to specific viruses
FALSE - restricted to enveloped
describe multinucleate syncytia
newly synthesized viral fusion proteins cause the fusion of infected cells with neighboring uninfected cells
T/F: multinucleate syncytia is a stealthy form of transmission as the virus remains intracellular
TRUE
why don’t all enveloped viruses use multinucleate syncytia
they lack mechanism (release kinetics) and have different replication needs
describe the formation of cell-to-cell bridges
filopedial or nanotubes
spread to other cells without exposing self to antibodies
describe the 4 steps of non-lytic release in vesicles
- vesicle forms around many virus particles in infected cell
- fuses with cell membrane to release “bag”
- “bag” binds to target cell
- “bag” dissolves and releases virus
