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39 Cards in this Set
- Front
- Back
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What kind of genome do retroviruses have?
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Double stranded (+) RNA that is not infectious.
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In what sort of manner is the DNA product of RT integrated into the host genome.
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Entirely random
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Where does retroviral assembly take place?
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Cytoplasm
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What are three families of retroviruses?
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1. Oncovirinae
2. Lentivirus 3. Spumavirinae |
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How would you describe a Type A retrovirus?
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It is an non-enveloped, endogenous virus that is not virulent.
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How would you describe a Type B virus?
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It is an enveloped virus with extracellular particles and a eccentric core.
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How would you describe a Type C virus?
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It is an enveloped virus with prominent spikes and a large central core.
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How would you describe a Type D virus?
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It is an enveloped virus with less-prominent spikes and a cylindrical core.
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What lines the envelope of a retrovirus? What codes for this?
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1. Matrix protein
2. GAG gene |
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What protects the core and is the most prominent thing in a virus? What codes for this?
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1. Capsid protein
2. GAG gene |
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What protects the genome? What codes for this?`
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1. Nucleocapsid
2. GAG gene |
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What neutralizes the charge on the RNA as well as condenses the RNA?
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Nucleocapsid
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What is involved in the maturation of the retrovirus?
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Protease must cleave the GAG polyprotein in order for the virus to become mature and virulent.
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What is responsible for making DNA from RNA in retroviruses? What other activity does this molecule have?
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1. Reverse transcriptase
2. RNAasH activity |
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What is needed for integration of the provirus? What encodes this?
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1. Integrase
2. Pol |
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What is the transmembrane protein for a retrovirus?
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gp41
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What is the surface protein for a retrovirus?
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gp120
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What are the transmembrane and surface proteins both made from?
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Precursor gp160
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What is encoded by the simple genome?
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Everything that is basic for the retrovirus.
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What is encoded by a complex retrovirus?
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It has everything that a simple retrovirus has plus additional genes.
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What are two additional genes that HLTV-1 has?
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Tax and Rex
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What is the function of the Tax gene in HLTV-1? What is the homologue in HIV?
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1. It is responsible for transactivation of the viral genes and also for turning on cellular genes in order to make the host cell more competent for viral replication.
2. TAT |
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What is the function of Rex in HLTV-1? What is the homologue in HIV?
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1. It is responsible for regulation of RNA splicing and export.
2. Rev |
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What gene in HIV is essential in the progression to AIDS?
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Nef
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What HIV gene is involved in viral releasal?
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Vpu
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What HIV gene is involved with getting the provirus into the host cell nucleus?
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Vpr
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Is HLTV-1 a tumor virus?
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Yes due to the fact that integration into the host can cause transformation.
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How does TAT work in HIV?
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It binds to TAR (stemloop region) and increases processivity by 1000x and thus causes the creation of a lot of mRNA.
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What are the doubly spliced HIV RNA products?
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TAT and REV
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What is exported slowly when there is defective REV?
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Singly spliced and unspliced mRNA.
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How does TAX actually function in HLTV-1?
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It binds to a Tax response element and recruits transcription factors (ie CREB/ATF) to enhance transcription.
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Most HLTV-1 infections end up being _______? A small percentage of HLTV cases end up with?
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1. Asymptomatic
2. T-cell leukemia or lymphoma |
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What is a disease that is often related to HLTV-1?
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Tropical spastic paraperesis
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How is HLTV-1 often diagnosed?
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ELISA antibody testing
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gp41 is surrounded by a trimer of what?
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gp120
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gp120 binds to what in order to initiate infection? What does this cause?
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1. CD4 receptor
2. Conformational change that allows binding to chemoreceptors (CCR5 and CXCR4) |
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What is a target of anti-fusion viral drugs?
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T20 fusian
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What is function of APOBEC? What virus gene combats this?
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1. It is a host factor that is a cytidine deaminase. It hypermutates the virus so it is no longer infectious.
2. Vif |
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What is the function of TRIM5α?
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Tears the viral RNA to shreds.
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