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18 Cards in this Set
- Front
- Back
The subdivision of the family herpeviridae is primarily based on? |
Cell tropism Genome organization |
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What are the 3 subfamilies and what are their characteristics? |
Alpha: short growth cycle, rapid spread, latent in sensory neurons Beta: long growth cycle, slow spread, restricted host range. Latent in secretory glands and lmphoreticular cells Gamma: growth primarily in epithelial cells and B or T lymphocytes. Latent in B cells |
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Herpesvirus infection typically involve? |
Acute replication followed by the establishment of lifelong latency |
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Lytic Infection: |
Thousands of new infectious viral particles produced 60-70 viral genes expressed |
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During latency, the herpesvirus genome is maintained as: |
An episome |
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HSV-1 virus particles consist of? |
Envelope spiked w/10 different virus glycoproteins Tegument w/14 free proteins Icosahedral capsid made of 6 virion proteins Linear dsDNA |
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Tegument proteins are released ________ entry and are crucial for establishing infection |
After |
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Although herpesvirus genome structures are variable, most ________ genes are cell conserved amoung herpesviruses. |
DNA replication |
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Herpesvirus tegument proteins play an important role in early stages of infection because they: |
Are real eased into the cytoplasm |
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List the steps involved with entry for HSV-1. |
1. Entry is mediated by envelope glycoproteins (gB and gC bind to heparin sulfate) 2. Binding triggers fusion of the virus envelope w/cellular membrane 3. Tegument proteins and capsid are released into the cytoplasm 4. Capsids detach from tegument and move toward nucleus 5. Capsid bind at nuclear envelope and release DNA into nucleus |
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Herpesvirus lytic gene expression follows a highly orders cascade in which the protein products of early genes? |
Facilitate viral DNA replication and transactivate the expression of late genes |
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List the steps that occur in HSV-1 rolling circle replication: |
1. One of parental DNA strands nicked, leading strand is pulled away from inner parent molecule 2. Additional DNA polymerase and process invite factor synthesize the complementar lagging strand 3. Generates a linear, dsDNA head to tail concatamer |
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List the steps in HSV-1 assembly: |
1. Immature capsid is assembled by accumulation of VPS and other proteins around a scaffold 2. Virus DNA entry into capsid is triggered when packaging machiner encounter packaging sites within the alpha segment of the genome 3. DNA packaging is complete when a full length genome is inserted and the machinery encounters another terminal alpha segment 4. Upon termination the scaffolding is dismantled and the scaffold proteins are ejected from capsid 5. Capsid changes conformation sealing the DNA inside the capsid |
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What are the 4 characteristics of latency? |
1. Non-productive infection 2. Maintenance of the viral genome as an episome 3. Few or no virus genes expressed 4. The ability to deactivate from latency |
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When herpesvirus enters local sensory neurons that innervate that site they lead the Nucleocapsid along the axon in ___________ transport |
Retrograde |
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What are the two most common types of HSV and what type of infections are they usually associated with? |
HSV-1: oral herpetic lesions (can also cause herpes storm all keratitis of the eye leads to blindness) HSV-2: genital herpetic lesions |
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Alpha HVs usually cause? |
Chickenpox Shingles HKS Oral herpetic lesions Genital herpetic lesions Encephalitis |
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What is the gamma herpesvirus that establishes life-long latency in B cells? |
Epstein Barr Virus (EBV) |