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45 Cards in this Set
- Front
- Back
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How do different papillomaviruses target different tissues?
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Different viral genotypes are tropic for specific body sites.
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What percentage of women have been exposed to various HPVs in their genitial mucosa?
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85%
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Are papillomavirus relatively successful in evading clearance by the immune system?
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Yes they are relatively successful.
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Can the primary HPV infection be latent?
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Yes
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What usually brings HPV out of latency?
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1. Things that promote immunosuppression
2. Tissue wounding |
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Infections with high risk HPV viruses lead to what?
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1. Dysplasia
2. Carcinoma |
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Are there any drugs that are effective at inhibiting HPV replication?
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No
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What type of genome does HPV virus have?
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DNA
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Where are the transcription enhancer and the promoter for HPV located?
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Upstream Regulatory Region (URR)
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What is the function of E6?
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Targets p53 for degradation via the 26s proteasome.
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What is the function of E7?
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Targets Rb for inactivation preventing it from interacting with E2F.
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Which viral genes are important for regulating viral replication?
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1. E1
2. E2 3. E4 4. E5 |
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What is the function of E2?
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It targets the URR and recruits E1 to the DNA enhancing replication.
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What is the function of E1?
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Recruited by E2, it enhances viral genome replication.
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What happens with very high levels of E2?
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Inhibits the binding of E1 and inhibits the replication of the viral genome.
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What forms the icosohedral capsid of HPV?
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1. L1 - major capsid protein
2. L2 - minor capsid protein |
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What cell type does HPV target initially?
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Basal cells in epithelium
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What is needed to allow the virus to initally infect?
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Insult to the epithelial basal cells.
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What form is E2 in when it binds to DNA?
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It is in a dimer.
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What enzymatic function does E1 have?
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It has helicase function.
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Do you get many copies of HPV due to infection of basal cells?
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No each cell divides and there is one copy of HPV in each. It is a slow process.
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Which viral products are expressed heavily early on in the infection process?
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At the basal level of the epithelium E6 and E7 are more heavily expressed.
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Which viral products are expressed as the level of infected cells moves up the stratum of the epithelium?
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As you move up the stratum, more products invovled in replication (E1 E2 E4 E5) are seen.
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What adenovirus viral products serve the same functions as E6 and E7?
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E1a and E1b
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What viral product in polyomavirus serves the same funtion as E7 and E6 in HPV?
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T antigen
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What does E2F recruit when it is not being inhibited by Rb? What blocks inhibition due to Rb?
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1. Histone acetyltransferases
2. E7 |
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What other molecule must E6 fight with in controling the cell cycle?
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p21
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Why does the HPV not want to transform the cells that it has infected?
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If the cell becomes transformed it can no longer reproduce the virus.
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What are alpha papillomaviruses trophic for?
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Muscosa of the anogenital tract
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Which HPV are associated with common warts?
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HPV 1-4
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What HPV is called meathandler's warts?
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HPV-7
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Which HPV types causes epidermodysplasia verruciformis?
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HPV 5 and 8
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Which HPV types are probably associated with squamous cell carcinoma?
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HPV 5, 8 and 16
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Which two HPVs are responsible for more than 70% of the infections that lead to cancer?
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HPV 16 and 18
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What is a way to grade cervical cancer?
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Cervical Intraepithelial Neoplasia scale 1-3
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What happens when the virus is integrated into the host's genome?
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The virus loses the genes that regulate replication so they may no longer replicate.
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What does the histology eventually look like when infected with HPV?
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Eventually the epidermis is dominated with transformed basal cells that can break through the basal epithelium and metastasize.
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In CIN 3 what viral gene product dominates the whole epithelium?
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E6/E7
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How is E2 releated to E6 and E7 and why would this matter in viral integration?
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1. E2 helps regulate E6 and E7 levels via feedback
2. Upon integration, E2 is lost so E6 and E7 is unchecked |
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Which HPVs cause genital warts?
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HPV-6 and HPV-11
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What is the problem with HPV and pregnant women?
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They can transmit the HPV-6 and HPV-11 to their baby which manifests in the form of Recurrent Respiratory Papilloma.
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What is the only way to correct RRP?
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Surgery
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What are some drugs that can be used to treat the RRP?
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1. Acutane
2. Interferons 3. Aldara 4. Vaccines |
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What is a HPV vaccine made out of?
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Viral capsids (L1) no DNA
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Which viral forms are included in the new prophylactic vaccines?
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1. HPV-6
2. HPV-11 3. HPV-16 4. HPV-18 |
