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39 Cards in this Set

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