Virology Lecture 4: Infectious Cycle - Attachment and Entry

Resistant cell = Cells that have no receptor for a given virus Class I fusion proteins = Proteins that mediate fusion at neutral pH in endosomes Permissive cell = Cells that have the capacity to replicate virus Virus entry = The process of a virus infecting a host cell

Attachment = Step where viruses adhere to cell surface randomly Acid-catalyzed membrane fusion = Proteins that mediate fusion at low pH in endosomes Susceptible cell = Cells that have functional receptors for a virus Gene expression = Step in the infectious cycle involving viral mRNA production and translation

Viral entry mechanisms = Various ways viruses enter host cells Class II fusion proteins = Proteins that mediate fusion at acidic pH in lysosomes Infectious cycle = The series of steps a virus takes to replicate inside a host cell Assembly and release = Step in the infectious cycle involving viral particles being put together and released from the cell

<p>Class I fusion proteins = Mostly α-helical Class II fusion proteins = Mostly β-sheet Acid-catalyzed membrane fusion = HA undergoes an acid-catalyzed conformational rearrangement, exposing a fusion peptide Viral entry mechanisms = Interaction of viral glycoprotein with cell receptor in the formation of fusion pore</p> Signup and view all the answers

<p>Class I fusion proteins = Perpendicular to membrane - spikes Class II fusion proteins = Form dimers Acid-catalyzed membrane fusion = Three states of influenza virus HA Virus entry = Fusion of viral and host cell membranes mediated by viral fusion proteins</p> Signup and view all the answers

<p>Class I fusion proteins = Proteolytic cleavage activates the fusion protein for cleavage Class II fusion proteins = Fusion is regulated and must not occur in the wrong location</p> Signup and view all the answers

<p>Reovirus = Entry involves uncoating at nuclear pore complex Adenovirus = Action of motor proteins aids in entry</p> Signup and view all the answers

<p>Parvovirus = Binds to pore and causes disruption for entry Influenza virus = Genome small enough to enter nuclear pore</p> Signup and view all the answers

<p>Plant Cell = Have rigid cell walls, require external trauma for viral entry Bacterial Cell = Have strong cell walls, some viruses exploit specialized structures for entry</p> Signup and view all the answers