M2-Group 5 (Non-segmented)

Question 1

Are Paramyxoviridae enveloped or non enveloped and what capsid do they have?

Answer 1

-Enveloped
-helical

Question 2

What group are Paramyxoviridae in?

Answer 2

Group 5–> (-) ssRNA

Question 3

Are Paramyxoviridae segmented or non-segmented?

Answer 3

Non-segmented

Question 4

What does it mean to be segmented or non-segmented

Answer 4

Non-segmented: Only 1 strand of RNA
Segmented: Multiple strands of RNA that makes up genome

Question 5

What pathogens are in Paramyxoviridae?

Answer 5

-Measles & mumps
-Parainfluenza
-Nipah & Hendra
-Rabies–>Rhabdoviridae

Question 6

True or false: Before the measles vaccine, it did not kill many people

Answer 6

False
-Before vaccine measles killed 2 million kids per year

Question 7

True or false: Measles has a low R0 value compared to other viruses

Answer 7

False
-Measles has the HIGHEST R0 value for a virus
-R0 = 12-18

Question 8

What are the reservoirs and amplifying host for Nipah and Hendra

Answer 8

Reservoir: bats
Nipah host: Pigs
Hendra host: Horses

Question 9

True or false: Nipah, Hendra, and Rabies can easily pass human to human

Answer 9

False
-usually dead end host because of high fatality rate

Question 10

Explain Paramyxovirus life cycle

Answer 10

1. Enters through fusion–>neutral pH
2. Polymerase is brought with virus
3. Buds off plasma membrane–>syncytia

Question 11

True or False: In Paramyxoviridae the genome is not bound by proteins

Answer 11

False
-Since helical genome is always wrapped in viral proteins
-Genome size is divisible by 6

Question 12

Differences between Icosahedral and Helical capsids

Answer 12

Icosahedral: Genome is not associated with proteins–>naked RNA
Can be immediately translated
Helical: Genome is bound by proteins –>Nucleocapsid, phosphoprotein, polymerase
Must be transcribed to make mRNA

Question 13

Where are structural and non structural proteins found on mRNA?

Answer 13

-Structural (nucleocapsid) at the beginning 3’ end –> N
-Non-structural (polymerase)–> 5’ end –>L

Question 14

What does polymerase stuttering do?

Answer 14

-Pol stutters at polyU to form polyA so that pol can reinitiate at start in intergenic region or go back to the beginning at 3’end

Question 15

What determines the switch from making short mRNA transcription to the whole genome replication

Answer 15

Levels of N protein –> nucleocapsid proteins
-when there is enough N proteins to coat the genome, pol will stop reinitiating & read the entire genome

Question 16

The expression of what protein cause infected cells to fuse with uninfected cells forming a?

Answer 16

-fusion (F) proteins
-form syncytia
-Paraymyxovirus

Question 17

Filoviridae: group, enveloped/non, capsid, segmented/non

Answer 17

-Group 5–>(-)ssRNA
-Enveloped
-Helical
-Non-segmented

Question 18

What pathogens are in Filoviridae?

Answer 18

Ebola and Marburg

Question 19

Filovirus life cycle

Answer 19

1. Entry through endosomes –> Low pH triggers
2. Viral polymerase is always brought with virus
3. Virus buds off plasma membrane–>secretes 2 types of glycoprotein from polymerase stuttering

Question 20

What is Ebola’s host receptor that is used to access cytoplasm?

Answer 20

NPC1

Question 21

True or false: Once viruses spillover they adapt to humans and replicate less in original reservoir

Answer 21

True
-Ex: virus binds better to human NPC1 than bat NPC1

Question 22

What does the P/C/V gene do?

Answer 22

Polymerase stuttering that causes “editing” or insertion of either 1 or 2 As
-changes frameshift–>causes overlapping reading frames & alternative starts

Question 23

In Filoviridae, how are 2 alternative versions of GP made?

Answer 23

-Full length GP is made ONLY when polymerase stutters & adds an extra base
-secreted sGP is made in high conc to be a decoy for antibodies–>nothing happens when it binds

Question 24

Ebola viral protein?

Answer 24

Glycoprotein

Question 25

Difference in stuttering for Paramyxoviridae and Filoviridae

Answer 25

-Paramyxoviridae: addition of As not essential for making proteins, happens occasionally
-Filoviridae: Glycoprotein is ONLY made when there is stuttering