Viruses

Question 1

HIV tropism, entry and infection

Answer 1

Tropism for lymphocytes
viral gp120 recognizes CD4 on host membrane
Chemokine receptors CXCR4 and CCR5 binds gp41 to allow viral entry
Use RevTrans to convert ssRNA to DNA
DNA is integrated into host genome by viral-encoded Integrase

Question 2

HIV replication

Answer 2

Uses host ribosomes to make envelope proteins and viral polyproteins, forms immature HIV virion
Uses viral-encoded protease to cleave polyprotein into viral proteins
Mature HIV released by budding without lysis

Question 3

HPV genome

Answer 3

dsDNA consist of 8 overlapping ORFs

L1 and L2 encode capsid proteins, E1-E7 encode replication proteins

Question 4

HPV Entry and infection

Answer 4

Infect basal epithelial cells, eg. keratinocytes

Maintained alongside host DNA as episomes (episomal DNA), or can be incorporated into host genome

Question 5

Replication of HPV

Answer 5

E6 and E7 proteins inhibit p53 and RB, prevent apoptosis and promote cell division

Question 6

Translation hijacking

Answer 6

Cleaving of eIF
Cap-snatching
IRES for cap-indie-transla