Herpesviridae & Poxviridae Flashcards
What group are Herpesviridae in?
Group 1–>dsDNA
What polymerase do Herpes use?
-HOST DNA dep RNA pol
-VIRAL DNA dep DNA pol
Are Herpes genome circular or linear
Linear
-biggest genome
Are herpes enveloped/non and capsid shape
-Enveloped
-Icosahedral
What 3 categories of herpes are there?
-Alpha (latent in neurons)
-Beta (latent in T cells)
-Gamma (cause cancer)
What viruses are in alpha?
-Herpes simplex virus 1 & 2 (TORCH)
-Varicella zoster
What viruses are in beta?
-Cytomegalovirus (TORCH)
-HHV6A, HHV6B, HHV7
What viruses are in Gamma?
-Epstein Barr
-Kaposis sarcoma associated herpesvirus
True or false: Herpesvirus does cross species transmission
False
-Herpesvirus does coevolution w/ humans–>good at staying hidden
-Less pathogenic
True or false: Herpesvirus has a lytic infection
False
-Latent infection
What is an episome?
Part of DNA that can replicate independently of host
Why is latency a concern for Herpesvirus?
-Virus can reactivate at anytime
-Long term expression of viral products that can cause transfromation/cancer
Where does latent virus reside in for long periods of time?
B lymphocytes and B memory cells
-these cells stay for life in body
What is the tegument in Herpesviridae
Area in between capsid and envelope
-contains proteins (14) that immediately interact w/ host
-delivers proteins set up for cell viral replication & antagonize host
Herpesviridae life cycle
- Entry: Fusion/endocytosis
- Nuclear entry & early proteins–>Immediate early & early (HOST DNA dep RNA pol)
- Genome replication–>Late proteins (VIRAL DNA dep DNA pol) assembled in NUCLEUS
- Exit: Exocytosis
How many waves of transcription/protein production does Herpesviridae have?
3 waves
1. Immediate early (HOST DNA dep RNA pol)
2. Early (HOST DNA dep RNA pol)
3. Late (VIRAL DNA dep DNA pol)
Herpesvirdae is linear how does it prevent degradation of ends?
Terminal repeat at ends
-makes genome circular by rolling circle mechanism
Poxviridae is part of which group?
Group 1–>dsDNA
Where does Poxviridae replicate?
Cytoplasm
What kind of polymerase do Poxviridae have?
-VIRAL DNA dep RNA pol
-VIRAL DNA dep DNA pol
Are Poxviridae enveloped/non
Enveloped
True or false: Poxviridae coevolve
False
-Jump host/cross species transmission
What pathogens are in Poxviridae
-Smallpox
-Monkeypox
-Tanapox
-Molluscum
-Animal-pox virus
What is important about smallpox?
-Killed millions
-Zoonotic transmission–>became human specific
-Led to first vaccines
-First human virus eradicated
True or false: Monkeypox, Cowpox, Chickenpox, etc come from that animal
False
-Name of virus is not reservoir, it is just where symptoms were seen
-Reservoir is most likely mouse
What was significant about the rabbits in Australia?
-Australia became over ran with rabbits
-Tried to kill rabbits with Myxoma virus (99.8% mortality rate)–>non pathogenic to Brazilian rabbits
-Not all rabbits died–>rabbits evolved resistance
Poxviridae life cycle
- Entry: fusion/endocytosis
- Early transcription & translation –> early VIRAL DNA dep RNA pol
- Genome replication–>intermediate proteins (VIRAL DNA dep DNA pol)
- Late Proteins
- Cell lysis
How many waves of transcription/protein production are there for Poxvirdae
3 waves
1. Early
2. Intermediate
3. Late
Poxviridae genome characteristics
-terminal repeats at ends
-ends are covalently linked (unlike adeno)
-stays linear (unlike herpes)
What 2 poxviral proteins block host immunity and how do they work?
- K3L–> binds to dsRNA indirectly blocks PKR and OASs
- E3L–>directly antagonizes PKR
How does PKR work?
-Protein kinase R (PKR) recognizes any dsRNA
-Phosphorylates eIF2a
-When eIF2a is phosphorylated prevents protein translation
Asfarviridae
-Group 1–>dsDNA
-Arbovirus (only dsDNA)
-causes fever in pigs
-enveloped
-viral pol
