Picornavirus Replication (+ strand) Flashcards
Where category do most picornaviruses fit into?
enterovirus
What is Baltimore classification based on?
the genome
Where is FMDV common?
India
Bangladesh - 23 mil cattle died
What does FMDV cause?
epithelial layer of the tongue sloughs off
What was the cost of the UK FMDV outbreak 2001?
£9-13Bn
6 million culls
What are the main causative agents of human HFMD
EV-A71
CVA16
children aged 1-4
associated with poliomyelitis-like disease
What happened to Funyan city with HFMD?
50% hospitalisation
- 8% severe cases
- 36% fatal cases
How is the RNA genome organised?
UTR at 3’ end
proteases
UTR important for regulation
What is a ribosome stuttering signal?
stops and re-engages
do not get readthrough for the site
2 diff proteins are made
What is at the 5’ end of the FMDV genome?
S fragment replaced by a cloverleaf
CRE - bind other replication proteins to form a complex in FMDV - S fragment takes role of cloverleaf
WHat is at the 3’ end of the FMDV genome?
AAA tail
binds RdRp - 3Dpol
Does the FMDV genome circularise during replication?
Yes probably
What is the role of CRE?
RdRp primer
CRE is an RNA stem loop - top of loop is free to pair
FMDV has 3 copies of the protein - quick replication
What does CRE template the addition of?
addition of uridine residues onto VPg
How is VPg cleaved before transltion
removal by TPD2 - leaves 5’monophosphate
helps to control translation
What do picronaviruses have in common?
same overall capsid structure
same overall genome organisation
How can polio progress to form a worse disease?
paralytic poliomyelitis
10% fatal
80% residual paralysis
How does polio infect cells?
binds to CD155 on mucosal epithelial cells
replicate in gut
infection of NS by retrograde transport along axons
How are there vaccine-derived polio cases?
mutation and recombination
prolonge poliovirus excretion
What are the 2 current polio vaccines?
OPV - mutant virus
IPV - inactivated virus
How can VLPs be generate in Pichia?
30 human doses per 200ml yeast
