HPV Flashcards
(32 cards)
What are a) alpha PV and b) beta PV also known as?
a) mucosal
b) cutaneous
What is the family PV is classified to?
Papillomaviridae
Give a brief structure of the PV genome?
8 kb, circular, double stranded, 7904 bp, URR (upstream regulatory region), many proteins: early (e1, 2, 4, 5, 6, 7) and late (L1 and L2).
Which early protein is commonly not expressed?
e5
How is HPV transmitted?
Sexual contact, micro-tears and abrasions in the epithelial layer
Name some cofactors that work with PV to cause benign or malignant cancers?
Bracken, sunlight, hormones, smoking and host genotype
How is HPV usually detected?
Smear tests
We’re are the ORFs of the HPV genome located?
On one strand of the DNA
What does the coding strand contain?
Approximately 10 designated ORFs, classified as early or late
What are early expressed ORFs?
E proteins: 1, 2, 4, 5, 6, 7 and 8.
They are expressed early, in non-productively infected cells.
Includes regulatory proteins and those required for genome replication.
What are late expressed ORFs?
L1 and L2.
Capsid proteins.
Expressed late only in productively infected cells.
What is LCR?
The long coding region, approximately 1 kbp, one in each genome, contains the Ori of DNA replication as well as important transcription factor control elements.
Which protein is for transcriptional regulation and DNA replication?
E2
Which proteins are for oncoprotein and cell cycle modulation/genome amplification? (Specify)
E5, genome amplification, and E6 and E7,cell cycle modulation.
Which protein has enzymatic activity?
Only E1, helicase activity for the initiation of DNA replication. All other enzymatic activation has to come from host.
What is E4 for?
Late expression to help the virus assemble and exit the cell
What are L1 and L2 functions?
L1: major capsid protein
L2: minor capsid protein
How do epithelial cells grow?
From basal stem layer and reserve to suprabasal then granular and then stratum corneum with cornification and sloughing.
How does HPV replicate with epithelial differentiation?
At the basal layer the genome is simply maintained and at suprabasal level the cell begins to proliferate causing genome amplification. At the granular level virus is assembled and released with cornification.
How can differentiating keratinocytes be looked at?
Using calcium in a mono layer however HPV cannot be produced using this method only certain stages of viral replication can be studied.
How can HPV be grown?
Organothpic raft culture: add HPV to epithelial cells, plate with collagen matrix, fibroblasts and culture media, grow to confluence and transfer submerged mono layer matrix to support grid to create a differentiating epithelium. In two weeks a striated epithelium will have formed.
What does confluence mean?
The proportion of the surface of the culture disk covered in cells. 100% is covered, 50% is half covered etc.
How does HPV enter?
At a micro-tear or abrasion in the epithelium, enters via a variety of methods, clathrin and non-clathrin coated vesicles, calveolae, via the endosomal pathway.
What does HPV do when it has entered?
Disassembly of the capsid occurs in the endosome and exposes the genome. L2 utilises the retro ER complex to traffic the genome into the cytoplasm, enter the nucleus and co localise with ND10 bodies, which may be the site of virus replication. L2 may enhance nuclear trafficking of the genome to transcriptionally active regions of the host genome, as it is inefficient.
