Deck 22: Papillomaviruses

Question 1

Which of the following is thought to be the reservoir for human papilomaviruses?

A)Cottontail rabbits
B)Surfaces contaminated with papillomaviruses.
C)Human male genital tract.
D)Human female genital tract
E)Both male and female genital tracts.

Answer 1

E

Question 2

Which of the following describes the mechanism used by the E6 protein of papillomaviruses to remove the p53 protein.

A)It causes the p53 protein to be exported out of the cell.
B)It causes the p53 protein to be targeted to the lysosome.
C)It causes the p53 protein to become ubiquinated.
D)It acts as a protease to directly degrade the protein.
E)It phosphorylates p53,which causes it to be degraded by the proteasome.

Answer 2

C

Question 3

The E2 protein from papillomaviruses can bind to the viral DNA and to mitotic chromosomes.What purpose might this serve for the virus?

A)It is important for regulating viral gene expression.
B)It assists with the replication of the viral chromosome.
C)It allows the viral DNA to be bound by cellular histones.
D)It allows the viral DNA to segregate to each daughter cell.
E)It improves the stability of the viral DNA.

Answer 3

D

Question 4

When the late promoter of papillomaviruses is activated,it increases production of the E1 and E2 proteins.Which of the following explains why an increase in these two proteins would contribute to vegetative replication of the virus?

A)They repress transcription for the early promoter.
B)They can cause the keratinocytes to become differentiated.
C)They initiate DNA replication of the viral genome.
D)They interact with the cellular protein pRb.
E)They interact with the cellular protein p53

Question 5

The E7 protein from papillomavirus stabilizes the cellular p53 protein,which leads to cell cycle arrest.Which of the following explains the mechanism by which p53 causes cell cycle arrest?

A)p53 activates transcription of p21,which blocks phosphorylation of pRb.
B)p53 binds to pRb and causes it to release the E2F transcription factor.
C)p53 binds directly to p21 and causes it to become degraded by the proteasome.
D)p53 binds to the viral E6 protein,which causes it to be degraded by the proteasome.
E)All of the above are correct.

Question 6

Papillomaviruses replicate in differentiated keratinocytes,which are not actively dividing.How does the virus handle this situation?

A)They encode their own DNA replication enzymes.
B)Plasmid replication in the basal cells produces enough copies of the viral genome.
C)The viral E2 protein directly activates transcription of DNA replication genes.
D)The viral E6 protein binds to the p53 protein,causing it to be degraded.
E)The viral E7 protein binds to the pRb protein,forcing the cell into S phase.

Question 7

The E6 proteins from highly oncogenic papillomaviruses have been shown to interact with cellular proteins,which control cell polarity and proliferation,that contain which of the following protein domains?

A)Zinc-finger domain
B)Activation domain
C)DNA binding domain
D)Homeobox domain
E)PDZ domain

Question 8

Which of the following proteins from papillomavirus can bind to the viral origin of DNA replication and unwind the DNA strands?

A)E1
B)E2
C)E6
D)E7
E)L1

Question 9

In papillomaviruses,plasmid replication produces a large number of viral genomes which will be packaged into new virions.

Question 10

The human papillomavirus can produce condylomas.What is the more common term to describe this type of skin lesion?

A)Rash
B)Genital wart
C)Canker sore
D)Cold sore
E)Skin ulcer.

Question 11

The papillomaviruses used to be classified in the same family as the polyomaviruses.Which of the following is a feature that distinguishes them from polyomaviruses?

A)Transcription of their genome only occurs on one strand.
B)Their genome is composed of double-stranded DNA.
C)Their virion is a naked capsid composed of 72 capsomeres.
D)Their genome is associated with cellular histones in a minichromosome.
E)They produce proteins that interact with pRb and p53.

Question 12

The E7 proteins from the oncogenic strains of papillomaviruses bind to pRb more tightly than the E7 proteins from nononcogenic strains of the virus.

Question 13

Mutations in the p53 gene are seen in over 50% of human tumors.

Question 14

The currently available HPV vaccines contain virus-like particles composed of which of the following?

A)L1 protein alone
B)L1 protein and viral DNA
C)L1 and L2 proteins.
D)L1 and L2 proteins and viral DNA.
E)E6 and E7 proteins.

Question 15

Which of the following cellular events causes the papillomavirus to enter "vegetative replication"?

A)Induction of the apoptosis pathway.
B)Entry into the S phase of the cell cycle.
C)Terminal differentiation of keratinocytes.
D)Cell division of the host cell.
E)Transformation into a cancer cell.

Question 16

Which of the following describes the form that the papillomavirus genome is found in most cervical cancer cells?

A)The entire viral genome is integrated into the genome of the host cell.
B)A fragment of the genome is integrated into the genome of the host cell.
C)The intact viral genome remains an episomal plasmid.
D)A fragment of the viral genome remains as an episomal plasmid.
E)Multiple copies of the genome are arranged in concatamers.

Question 17

Productive infections with human papillomaviruses have been difficult to study in cultured cells.Which of the following explains why?

A)They only infect human cells in culture.
B)They only produce a few virions per infectious cycle.
C)The viral particles are difficult to purify.
D)They only produce virions in differentiated keratinocytes.
E)They induce a strong interferon response in infected cells.

Question 18

Which of the following describes the best treatment for papillomavirus induced cervical lesions?

A)Vaccination with the vaccine against HPV.
B)Radical surgery to remove the uterus and cervix.
C)Removal of the lesion using a laser.
D)Injection of antibodies against HPV into the lesion.
E)Giving the patient systemic anticancer drugs.

Question 19

The cultured human cell line HeLa expresses the E6 and E7 proteins of human papillomavirus.What would happen to these cells if the expression of these proteins was shut off?

A)They would continue to grow at their usual pace
B)They would continue to grow,just more slowly.
C)They enter the G₀ phase of the cell cycle.
D)They go into apoptosis and die.
E)They become even more tumorigenic.

Question 20

Cervical tumors caused by human papillomavirus do not show the typical mutations in the p53 gene that most cancer cells have.Which of the following explains why?

A)The virus is not sensitive to the effects of p53.
B)The E6 protein causes the degradation of the p53 protein.
C)Apoptosis does not occur in cervical epithelium.
D)Cervical epithelial cells do not express p53.
E)The E7 protein binds to pRb,preventing it from inducing apoptosis.

Question 21

Very few cases of cervical cancer are caused by infection with papillomavirus.

Question 22

The Pap test,named after George Papanicolaou,screens for the presence of cancer cells in the cervix.

Question 23

Explain the roles that plasmid replication and vegetative replication play in the life cycle of papillomaviruses as they infect stratified epithelium.

Question 24

Discuss the differences between the oncogenic papillomaviruses,strains 16 and 18,from the more benign virus strains that lead to higher incidence of cervical cancer.

Question 25

Cervical cancer cells,which have been transformed by the papillomavirus,are still capable of producing large amounts of virus particles.