M2-Coronaviridae

Question 1

What group are Coronaviridae in?

Answer 1

Group 4–>(+)ssRNA

Question 2

Are Coronaviridae enveloped or non-enveloped?

Answer 2

Enveloped

Question 3

What are the pathogens of Coronaviridae?

Answer 3

-Severe Acute Respiratory Syndrome (SARS)
-Middle East Respiratory Syndrome (MERS)
-common cold

Question 4

What is the reservoirs for SARS corona virus?

Answer 4

Bats/civet cats

Question 5

What is the reservoir for MERS corona virus?

Answer 5

Camels

Question 6

Does SARS or MERS have a higher fatality?

Answer 6

MERS

Question 7

Which SARS or MERS spreads human to human well?

Answer 7

SARS
-MERS has a high fatality so it doesn’t spread well

Question 8

Why does SARS-CoV-2 spread more widely than SARS even though their R0 values are similar?

Answer 8

-Longer incubation period
-More Asymptomatic cases–>people spread virus w/out knowing
-No social distancing/quarantine
-Did not learn lesson from first SARS outbreak

Question 9

What is the viral envelope protein and host receptor for coronavirus?

Answer 9

-Viral envelope protein: Spike protein
-Host receptor: ACE2

Question 10

If a human gets covid can it reinfect the bat?

Answer 10

No spike protein will not fit bat ACE2 only human ACE2

Question 11

True or false: Coronaviridae do not make a polyprotein and do not use proteases

Answer 11

False
-Make a polyprotein that is cleaved by proteases

Question 12

True or false: Coronaviridae can make more than 1 mRNA

Answer 12

True

Question 13

What are the 3 major differences between Togaviridae and Coronaviridae subgenomic RNAs?

Answer 13

1. Togaviridae only make 1 subgenomic RNA while coronaviridae makes multiple
2. Togaviridae makes subgenomic RNA during (+) strand synthesis makes whole genome or subgenomic and Corona makes it during (-)strand synthesis
3. Corona makes subgenomic during discontinuous transcription

Question 14

What kind of shape do coronavirus virions have?

Answer 14

Helical

Question 15

Where do Coronaviridae replicate?

Answer 15

Replicate on membrane–Endoplasmic reticulum

Question 16

What other family replicates on Endoplasmic Reticulum like Coronaviridae does?

Answer 16

Flaviviridae and Togaviridae

Question 17

Because Coronaviruses are huge what is a unique capability that they have?

Answer 17

Encodes a subunit of polymerase that has PROOFREADING CAPABILITY

Question 18

What would happen if we could inhibit Coronavirus proofreading capability?

Answer 18

If Coronavirus had no proofreading capability than it could make enough mutations to push it over error threshold & stop replication

Question 19

If we were going to target the viral life cycle what are 2 potential targets?

Answer 19

1. RNA polymerase
2. Protease

Question 20

What does paxlovid target?

Answer 20

3CL protease for COVID

Question 21

HIV and HCV have cocktails that target polymerase inhibitor, why do they use a cocktail?

Answer 21

-Viruses can evolve, but a cocktail targets many things at once so it is hard for the virus to evolve

Question 22

What are some host targets for drugs?

Answer 22

-Spike protein
-TMPRSS2 (host protease)

Question 23

What is an advantage and disadvantage for targeting host instead of virus?

Answer 23

Advantage: We won’t evolve
Disadvantage: Targets humans

Question 24

What can antiviral cytokines activate

Answer 24

Innate and adaptive immune response

Question 25

True or false: Anti-inflammatory drugs can dampen pathogenesis from viral infection

Answer 25

True

Question 26

What are the differences between Picornaviridae, Flaviviridae, Togaviridae, and Coronaviridae for structural & non-structural protein expression

Answer 26

-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

Question 27

What proteins do you expect the structual proteins and non-structural proteins to make

Answer 27

Structural: Nucleocapsids Non-structural: RNA polymerase

Question 28

How does coronavirus make multiple subgenomic RNA

Answer 28

Discontinuous transcription -every time it sees a TRS sequence it hops to 5’ end and repeats process for however many TRS sequences there are

Question 29

What is an advantage to discontinuous transcription

Answer 29

-all have same 5’ end don’t have to encode it -polymerase can transcribe efficiently