HPV life cycle and replication strategy Flashcards
How common is HPV infection?
90% of sexually active men and 80% of women will be infected .
What percentage of HPV infections involves high risk types linked to cancer
50% of infections
What type of geentic material does HPV have
Double stranded circular DNA (8kb)
How is HPV classified ?
Alpha-PVs :Mucosal ,linked to anogenital cancers
Beta-PVs :cutaneous ,associated with non melanoma skin cancer
What are rhe major functions of the HPV early and late proteins ?
Early(E1-E7) Regulation ,replication ,transformation
Late (L1,L2) :capsid formation ,productive infection
What is the function of the e1 protein?
It acts as a helicase and initiates DNA replication.
How does HPV enter host cells ?
Through endocytosis ,assisted by the L2 protein
What promoter is active in undifferentiated cells leading to E6/E7 expression?
the P97 promoter .
How does HPV activate the MAPK pathway?
Through the actions of the E5,E6 and E7 ,which enhance cell cycle progressiion and viral transcription .
How many copies of HPV DNA are maintained in basal epithelial cells ?
50-100 copies per cell
in which epithelial layer does productive HPV replication occurs?
Terminally differentiated epithelial cells
How does HPV ensure immune evasion?
By using a non-lytic release process ,preventing strong immune detection
What protein helps in virion release by disrupting the keratin network?
E4 protein
How has HPV research contributed to cancer biology
It has advanced understanding of cellcycle regulation , tumour suppressor pathways and antivirals strategies .
