RNA Positive Polarity Virus Replication: Picornaviridae

Question 1

Picornaviridae (5):

Answer 1

• Single stranded, non-segmented RNA.
• Positive polarity.
• Icosahedral capsid.
• No envelope.
• Stable to acid (except rhinoviruses) and the environment.

Question 2

+RNA virus families (3):

Answer 2

• Picronaviridae.
• Togaviridae.
• Coronaviridae.

Question 3

Picornaviridae attachment (3):

Answer 3

• Attaches to cell receptor PVR or CD155.
• Loses VP-4 protein from capsid.
• Penetration by viropexis (endocytosis).

Question 4

Picornaviridae uncoating occurs in:

Answer 4

Cytoplasm.

Question 5

Picornaviridae replication occurs in:

Answer 5

Cytoplasm.

Question 6

Picornaviridae translation:

Answer 6

• VPg is lost.

- +RNA is translated into polyprotein P123.

Question 7

Picornaviridae viral protein 3D:

Answer 7

RNA dependent-RNA polymerase.

Question 8

Picornaviridae replication (3):

Answer 8

• Viral RNA polymerase + host factor (HF).
• +RNA is converted to many -RNAs (replicative intermediate, RI).
• -RNA is copied into +RNAs.