Lec 8 - RNA virus replication 2

Question 1

What virus is in Baltimore group 5 and what do they need to encode?

Answer 1

(-) ssRNA viruses eg influenza always need RdRp

Question 2

List the proteins in each part of influenza’s structure

Answer 2

Envelope: HA, NA, M2 ion channel
Matrix: M1 matrix protein
Genome: 8 segments bound by NPs to form RNPs and all bound by PB1, PB2 and PA

Question 3

How does influenza get a 5’ cap for its mRNA?

Answer 3

Cap snatching: PB2 cap binding motif binds host mRNA, PA cleaves it, RdRp copies it

Question 4

What Baltimore group is rotavirus in?

Answer 4

Group 3 dsRNA virus

Question 5

How does rotavirus evade innate immune receptors that detect dsRNA?

Answer 5

Triple capsid dissociates to fenestrated double layered particle (DLP) where mRNA is made and released through pores

Question 6

Describe rotavirus’ replication cycle

Answer 6

1. Endocytosis and uncoating to DLP
2. mRNA synthesis in DLP
3. Assembly in viroplasm
4. Capsid modified in ER
5. Release by lysis or exocytosis

Question 7

What 2 proteins does rotavirus use to evade immunity and how do they function?

Answer 7

1. NSP1 to interfere with IFN
2. NSp3 to inhibit host translation