Exam 4 - Lecture 9 Flashcards
Review the basic properties of RNA viruses
Viruses that have either a ssRNA or dsRNA genome and use viral RdRp to replicate their
genome
- genome is either linear or circular
Most replicate in the cytosol
Reoviruses general
- What is special about their genomes and capsids?
segmented genomes enclosed in double icosahedral capsids
all are naked viruses, and some have glycoproteins embedded in the capsid (very rare)
Reoviruses general
- How do they get into cells and why don’t they fully uncoat?
Enter via endocytosis and escape the endosome
They never fully uncut their genome because they don’t want their genome to activate dsRNA cellular immunity
Reoviruses general
- What does the genome look like when it is packaged?
- Why is their budding process strange?
Initially package just +sense RNA into inner capsids, and makes the -sense strand inside the capsid
Some bud into the ER and obtain a temporary envelope that has glycoproteins, and keeps the glycoproteins that it acquires during this when it escapes from the membrane
Reoviruses – rotavirus
- What do the virions look like?
- What disease does it cause?
- How is it transmitted and how contagious is it?
Virions look like wheels (rota = wheel)
Causes severe watery diarrhea, transmitted by the fecal-oral route (diarrhea releases virions into water sources, onto hands,
and onto objects, and those enter into another person’s mouth)
Highly contagious, with only 100 virions needed
Reoviruses – rotavirus
- What causes the diarrhea?
- What functions does NSP4 have?
Diarrhea occurs as a result of viral-induced death of intestinal enterocytes, disruption of tight junctions, and combined effects of the viral enterotoxin NSP4
Reoviruses – rotavirus
- What functions does NSP4 have?
NSP4 alters cytosolic Ca2+ levels which triggers the opening of Cl- channels in the PM
- also blocks reabsorption of glucose and water
- induces lactose intolerance
Reoviruses – blue-tongue
- What disease does it produce (symptoms)?
- How is it transmitted?
- What cells do they infect and what happens to those cells?
Reoviruses – blue-tongue
- What disease does it produce (symptoms)?
- How is it transmitted?
- What cells do they infect and what happens to those cells?
Reoviruses – blue-tongue
- What disease does it produce (symptoms)?
- How is it transmitted?
- What cells do they infect and what happens to those cells?
Know basics about + sense RNA viruses
Picornaviruses
- Know its unique structural characteristics
Picornaviruses - Poliovirus
- What is special about the virion itself?
- How is the virus transmitted?
- What types of symptoms are commonly/uncommonly seen?
- What types of paralysis occur as a result of infection?
Picornaviruses - Poliovirus
- What is special about the virion itself?
- How is the virus transmitted?
- What types of symptoms are commonly/uncommonly seen?
- What types of paralysis occur as a result of infection?
Picornaviruses - Poliovirus
- What is special about the virion itself?
- How is the virus transmitted?
- What types of symptoms are commonly/uncommonly seen?
- What types of paralysis occur as a result of infection?