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39 Cards in this Set
- Front
- Back
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What are the stages of the viral life cycle?
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Attachment
Entry Genome expression an replication Assembly Exit |
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Where in the viral life cycle to things go wrong and ocogenesis occurs as a result? Why?
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Assembly and exit.
The viruse is still inducing the cell into S phase but the cell isn't being lysed. |
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What stage of the cell cycle do viruses want the cell to be in? Why?
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The S phase
They want DNA synthesis to be active, so that they can take advantage of the machinery |
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Where is the location of oncognic DNA virus replication?
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Nuclear
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What two pathways do the oncogenic DNA viruses isrupt?
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pRB
p53 |
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What is the function of pRb?
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Binds to E2F. If phosphorylated, pRb dissociates from E2F, sitimulating the entry into S phase
This is disrupted in viruses |
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What is the function of p53?
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Blocking entry into S when the cell should not be going into S
Also, detection of unneeded NA synthesis --> Apoptosis |
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What is a common response to viral infection? What is the viruses response to this?
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Apoptosis of the cell
Blockage of apoptosis; want to keep the cell alive as long as possible to spread viruses |
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What is the low risk symptom caused by HPV?
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Benign warts
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What is the cause of benign warts?
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HPV
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What is the high risk manifestation of HPV?
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Cancer: cervical, anal, penile, oral
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What can cause oral, penile, cervical, and anal cancers?
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HPV
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When inside the body, where does HPV first go? What does it do there?
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The dermis.
Is truly latent; produces early HPV proteins |
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What is the cue for HPV viral assembly?
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Differentiation of the skin cells provides the stimulation for viral assembly.
DNA gets integrated into the cell |
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What is the protein that HPV interacts with inside the skin?
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E2
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What is the role of E2 in the skin?
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Repression of the E6 and E7 proteins, which are oncoproteins
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What is the mechanism of oncogenesis in HPV?
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The HPV DNA is inserted inside the E2 gene, derepressing E6 and E7
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What is the activity of the E7 protein in epithelial cells?
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Entrance of the cell into the S phase by binding to pRb
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What protein binds to pRb in epithelial cells, causing entry into S phase?
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E7 protein
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What is the function of E6 in epithelial cells?
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Degradation of p53 --> prevents the cell from undergoing apoptosis.
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Does the HPV virus encode its own DNA synthesis machinery?
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No!
It uses the host cell's machinery? |
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What is the one protein that HPV brings along with it?
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Helicase
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What is the structure of the HPV vaccine?
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Recombinant viral proteins from the capsid (L1)
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What is the goal of the HPV vaccine
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Prophylaxis - if you have the vaccine, you most likely won't get cervical cancer
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What is one reason that the liver is a fertile place for viral growth?
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The tissue keeps on growing back - promethus
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What viruses can cause hepatocellular carcinoma?
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HBV
HCV |
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What types of proteins does HBV and HCV express?
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Proteins that stimulate cell division
Proteins that stimulate DNA repair |
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What type of cancer can EBV cause?
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Burkitt's lymphoma
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What kind of virus can cause Burkitt's lymphoma?
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EBV
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What is the mechanism of carcinogenesis in burkitt's lymphoma?
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Translocation of the c-myc gene into the immunoglobulin locus --> increased expression.
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What are the proteins that transform cells in an EBV viral infection?
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Epstein barr Nuclear Antigens
Latent membrane proteins |
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What is the function of the Epstein barr Nuclear Antigens?
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Activation of signal transduction pathways
Inhibition of turmor suppression pathways |
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What is the function of the Latent membrane proteins in EBV?
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Stimulation of proliferation and survival pathways
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What is the virus that causes Kaposi's sarcoma?
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KSHV/HHV-8
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What is the disease that KSHV/HHV-8 causes?
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Kaposi's sarcoma
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What is the mechanism of virulence for KSHV/HHV-8?
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Encoding cellular mimics:
v-cyclin v-IL6 v-Bcl2 |
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What is the function of v-cyclin in KSHV/HHV-8?
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Kinase activator; stimulates entry into S phase
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What is the function of v-IL6 in KSHV/HHV-8?
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Growth factor for cells under certain pathways
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What is the function of v-Bcl2 in KSHV/HHV-8?
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Anti-apoptotic cellular protein
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