Negative-strand RNA viruses

Question 1

Give 3 segmented genome viruses

Answer 1

Arenaviruses
Bunyaviruses
Orthomyoxoviruses

Question 2

Give 3 defining characteristics of negative strand RNA viruses

Answer 2

1. The RNA genome is non-coding
2. They carry an RNA polymerase into new cells
3. The RNA genome is not naked it is wrapped in nucleocapsid protein which forms a ribonucleoprotein complex

Question 3

How does N-RNA interact?

Answer 3

Via the phosphate backbone electrostatically. Can hide from RNase in the cleft.

Question 4

What is VSV?

Answer 4

Vesicular stomatitis virus, a good model because it has few genes and is non-segmented with 5 genes

Question 5

What are the 5 proteins in the VSV genome?

Answer 5

1. Nucleocapsid protein N
2. Phosphoprotein P (an RdRp cofactor)
3. Matrix protein X (links with glycoproteins to form the virus particle)
4. Glycoprotein G (forms trimer spikes for attachment)
5. Large protein (L) RdRp

Question 6

What are the basic stages of transcription?

Answer 6

1. RdRp binds to the negative genome
2. Locates the gene start (nt44)
3. Responds to signals in the genome to stop copying and begin again

Question 7

Which proteins are required for transcription?

Answer 7

P and L

Question 8

How is a gradient of transcription created?

Answer 8

The RdRp can fall off the template at the gene junctions

Question 9

RNA replication in comparison to transcription

Answer 9

1. Begins at position 1 not 44
2. Ignores gene junctions
3. Wrapped in N protein as it is formed

Question 10

How do we test is the gradient is important?

Answer 10

Move the genes around