L9 - HPV (1)

Question 1

How are PVs classified?

Answer 1

sequences of the L1 major capsid protein

Question 2

What are Alpha-PVs?

Answer 2

mucosal

ano-genital cancers

Question 3

Examples of Alpha-PVs?

Answer 3

HPV16

HPV18

Question 4

What are Beta-PVs?

Answer 4

cutaneous

non-melanoma skin cancer

Question 5

How is the HPV genome organised?

Answer 5

all ORFs located on 1 strand of the DNA

10 ORFs - Early or late

LCR - contains origins of DNA replication, TFs

Question 6

When are Early genes expressed?

Answer 6

in non-productive infected cells

non-structural proteins to reconfigure environment

Question 7

When are late genes expressed?

Answer 7

in productively infected cells

structural proteins - capsid

Question 8

E1?

Answer 8

helicase

initiate DNA replication

Question 9

E2?

Answer 9

transcriptional regulation

DNA replication

Question 10

E4?

Answer 10

late early protein

virus assembly/release

Question 11

E5?

Answer 11

Oncoprotein and genome amplification

Question 12

E6/E7?

Answer 12

Oncoprotein and cell cycle modulation

Question 13

L1

Answer 13

Major capsid protein

Question 14

L2

Answer 14

Minor capsid protein

Question 15

What is the HPV life cycle dependent on?

Answer 15

keratinocyte differentiation

Question 16

What happens when a cell detaches from the basement membrane?

Answer 16

switch in transcriptional programme

drastic morphologial change

withdraw from cell cycle

dead cell - gets rid of organelles - makes physical barrier of epithelium

HPV hijacks this process

Question 17

How to culture HPV?

Answer 17

dermal equivalent collagen matrix with culture media on top

dispersed primary keratinocytes

creates a differentiating epithelium

Question 18

How does HPV enter cells

Answer 18

disassembly of capsid - exposure of genome within endosome

L2 - retromer complex - genome into cytoplasm

enter nucleus - colocalise at PML bodies

AVOIDS DETECTION BY IMMUNE SYSTEM (cGAS)

Question 19

How is PV transcription complex?

Answer 19

multiple promoters

alternate splice patterns

differentiation of mRNA production

Question 20

What is the PV early promoter?

Answer 20

P97 -UNDIFFERENTIATED CELLS

expressed E6, E7

Question 21

What is the PV late promoter?

Answer 21

differentiation-dependent = P670

E4/L1/L2 (E1)

Question 22

How is Transcription regulated in PV?

Answer 22

Cis elements

LCR contains enhancer elements

Question 23

What binding sites does the LCR contain?

Answer 23

binding sites for E2 protein

Question 24

What do E2 regulatory proteins contain?

Answer 24

sequence-specific DNA binding & dimerisation domain - carboxyl terminus

transactivating domain - amino terminus

Question 25

What does PV replication require in cis and trans?

Answer 25

cis - DNA ORI

trans - E1, E2

Question 26

What does the efficient replication of PV depend on?

Answer 26

association of E1 and the S-phase specific cyclin E complex

E2 stabilised he E1-Ori interaction

Question 27

Job of E1 in PV replication?

Answer 27

bring in rest of host cell replication machinery

functions at ATP-dependent helicase

Question 28

Why is driving the cells into S-phase necessary?

Answer 28

allow viral DNA replication in the stratified epithelium in a PROLONGED G2 PHASE

suprabasal cells usually exit cell cycle & differentiate - in E5/E6/E7 expressing cells - terminal differentiation delayed

Question 29

What do late functions include?

Answer 29

vegetative DNA synthesis
capsid protein synthesis
virion assembly

EXCLUSIVE TO DIFFERENTIATED KERATINOCYTES

GOOD FOR IMMUNE EVASION

accumulated of the late early gene E4

Question 30

What happens during PV assembly and release?

Answer 30

accumulation of late gene products

move L2 to nucleus - associated with PML bodies

L1 as capsomeres in cytoplasm - translocate to nucleus - interact with L2 and PMLs

encapsidation??

E4 protein disrupts keratin network - effect integrity of cornified envelope