Picornaviruses, Corona viruses, Orthomyxoviruses- Lecture 10/21/21

Question 1

Picornavirus genome

Answer 1

Single stranded RNA plus strand, 11-15 proteins

Question 2

Picornavirus capsid

Answer 2

Icosahedral

Question 3

Is picornavirus enveloped?

Answer 3

No

Question 4

Picornavirus entry

Answer 4

Receptor mediated, capsid proteins form pore in endosome

Question 5

Picornavirus multi protein method

Answer 5

Polyprotein, self cleavage

Question 6

VpG

Answer 6

Protein that forms on 5’ end of mRNA, also serves as a primer for replication

Question 7

IRES

Answer 7

Internal ribosome entry site, specialized RNA structure that ribosomes recognize

Question 8

Picornavirus proteases

Answer 8

2A and 3Cpro

Question 9

RdRP

Answer 9

RNA dependent RNA polymerase, synthesizes the anti genome complementary RNA

Question 10

Picornavirus virion assembly

Answer 10

VPs spontaneously assemble into capsids, only (+) RNA encapsulates, occurs entirely in cytoplasm, kills cell to release

Question 11

Coronavirus genome

Answer 11

Single stranded RNA plus strand ~30 kb >20 proteins

Question 12

Coronavirus capsid

Answer 12

Helical

Question 13

Is coronavirus enveloped?

Answer 13

Yes

Question 14

Coronavirus membrane proteins (3)

Answer 14

Spike glycoproteins, membrane protein, small envelope protein

Question 15

Special capability of coronavirus RdRP

Answer 15

Can proofread

Question 16

Method f coronavirus multiple proteins

Answer 16

Polyprotein and Nested mRNAs

Question 17

Two conserved coronavirus poly proteins

Answer 17

Code for necessary proteins including RdRP and proteases

Question 18

Subgenomic mRNAs

Answer 18

Brought by ribosomal frameshift, encode for structural and accessory proteins, virus-specific

Question 19

Coronavirus entry method

Answer 19

Either fusion at plasma membrane or endocytosis, needs to recognize ACE2 either way

Question 20

TMPRSS2

Answer 20

Cleaves spike protein at the plasma membrane, triggering fusion

Question 21

Cathepsin L

Answer 21

Cleaves spike protein in lysosome, triggering fusion

Question 22

Coronavirus egress

Answer 22

Buds from the ER and release by secretory pathway

Question 23

Example of orthomyxovirus

Answer 23

Influenza

Question 24

Influenza A

Answer 24

SUbdivided by antigenicity by surface proteins Hemagglutinin(HA) and Neuraminidase (NA) where we get H1N1 nomenclature

Question 25

Genome of influenza

Answer 25

Single stranded RNA minus strand, 7-8 segments ~14 protiens

Question 26

Influenza capsid

Answer 26

Helical capsid, one per segment

Question 27

Is influenza enveloped

Answer 27

Yes

Question 28

Envelop protein contents (3)

Answer 28

• neuraminidase
• hemagglutinin
• Matrix protein 2 (Ion channel)

Question 29

Influenza virus entry

Answer 29

Only endocytosis, then trafficked to the nucleus for gene expression (Unusual for RNA)

Question 30

Receptor ligand interaction for influenza

Answer 30

HA on the virus and sialic acid on cell

Question 31

Transcription of influenza

Answer 31

Done by RdRp, after cleaving 5’ cap from a cellular mRNA

Question 32

Replication of influenza genome

Answer 32

RdRp makes cRNA without using 5’ cap primer, that cRNA used to replicate genome

Question 33

RNPs

Answer 33

Np protein protects genomic RNA from detection by the cell, have nuclear import signals recognized by cell

Question 34

NS1

Answer 34

Master influenza protein used to stop IFN type I and III signaling

Question 35

Influenza virus egress

Answer 35

Budding at the plasma membrane

Question 36

Neuroamidase activity

Answer 36

Cleave HA so that it does not reinfect cell it just left

Question 37

Antigenic shift

Answer 37

If more than one virus infects one cell, genome segments shuffle during reassembly generating up to 256 different variants

Question 38

Antigenic drift

Answer 38

Mutations arise randomly leading to loss or gain of fitness, and changes antigenicity