M2-Coronaviridae Flashcards
What group are Coronaviridae in?
Group 4–>(+)ssRNA
Are Coronaviridae enveloped or non-enveloped?
Enveloped
What are the pathogens of Coronaviridae?
-Severe Acute Respiratory Syndrome (SARS)
-Middle East Respiratory Syndrome (MERS)
-common cold
What is the reservoirs for SARS corona virus?
Bats/civet cats
What is the reservoir for MERS corona virus?
Camels
Does SARS or MERS have a higher fatality?
MERS
Which SARS or MERS spreads human to human well?
SARS
-MERS has a high fatality so it doesn’t spread well
Why does SARS-CoV-2 spread more widely than SARS even though their R0 values are similar?
-Longer incubation period
-More Asymptomatic cases–>people spread virus w/out knowing
-No social distancing/quarantine
-Did not learn lesson from first SARS outbreak
What is the viral envelope protein and host receptor for coronavirus?
-Viral envelope protein: Spike protein
-Host receptor: ACE2
If a human gets covid can it reinfect the bat?
No spike protein will not fit bat ACE2 only human ACE2
True or false: Coronaviridae do not make a polyprotein and do not use proteases
False
-Make a polyprotein that is cleaved by proteases
True or false: Coronaviridae can make more than 1 mRNA
True
What are the 3 major differences between Togaviridae and Coronaviridae subgenomic RNAs?
- Togaviridae only make 1 subgenomic RNA while coronaviridae makes multiple
- Togaviridae makes subgenomic RNA during (+) strand synthesis makes whole genome or subgenomic and Corona makes it during (-)strand synthesis
- Corona makes subgenomic during discontinuous transcription
What kind of shape do coronavirus virions have?
Helical
Where do Coronaviridae replicate?
Replicate on membrane–Endoplasmic reticulum
What other family replicates on Endoplasmic Reticulum like Coronaviridae does?
Flaviviridae and Togaviridae
Because Coronaviruses are huge what is a unique capability that they have?
Encodes a subunit of polymerase that has PROOFREADING CAPABILITY
What would happen if we could inhibit Coronavirus proofreading capability?
If Coronavirus had no proofreading capability than it could make enough mutations to push it over error threshold & stop replication
If we were going to target the viral life cycle what are 2 potential targets?
- RNA polymerase
- Protease
What does paxlovid target?
3CL protease for COVID
HIV and HCV have cocktails that target polymerase inhibitor, why do they use a cocktail?
-Viruses can evolve, but a cocktail targets many things at once so it is hard for the virus to evolve
What are some host targets for drugs?
-Spike protein
-TMPRSS2 (host protease)
What is an advantage and disadvantage for targeting host instead of virus?
Advantage: We won’t evolve
Disadvantage: Targets humans
What can antiviral cytokines activate
Innate and adaptive immune response
True or false: Anti-inflammatory drugs can dampen pathogenesis from viral infection
True
What are the differences between Picornaviridae, Flaviviridae, Togaviridae, and Coronaviridae for structural & non-structural protein expression
-Picorna and Flavi are inefficient since they express non-structural/structural proteins at the same time and level
-Togaviridae–>structural proteins expressed at same level but at a diff level than non-structural
-Coronaviridae–>structural proteins can be expressed at different levels b/c each one is on a diff transcript
What proteins do you expect the structual proteins and non-structural proteins to make
Structural: Nucleocapsids
Non-structural: RNA polymerase
How does coronavirus make multiple subgenomic RNA
Discontinuous transcription
-every time it sees a TRS sequence it hops to 5’ end and repeats process for however many TRS sequences there are
What is an advantage to discontinuous transcription
-all have same 5’ end don’t have to encode it
-polymerase can transcribe efficiently
