Flashcards in L34_DNA Viruses 1 Deck (32):
Where does transcription and replication take place for DNA viruses?
The nucleus (except pox)
Is the host or virus RNA polymerase used to transcribe mRNA?
Host (except pox)
Does the host or viral DNA polymerases replicate the genome
What are the two common viral transcription factors that help enhance ciral transcription?
X and Y
Are promoters in viral genomes recognized by host or viral transcription factors, or both?
Give some examples of viruses that use their own DNA polymerase.
Herpesviruses and Adenovirus
Do DNA viruses mutate faster or slower than RNA viruses? Why?
Slower, DNA polymerases have much higher fidelity and are capable of proofreading. (Recombination can still happen when a Polymerase hops strands)
What are some common symptoms of Adenovirus affecting the respiratory system? how about other sites?
Respiratory: A bad cold with a fever, pharyngoconjuctival fever, Laryngitis and cough, pneumonia
Other Sites: Acute hemorrhagic cystitis, epidemic keratoconjunctivitis, gastroenteritis
How is adenovirus transmitted?
Aerosol, Fecal-oral, objects, poorly chlorinated swimming pools
What are the susceptible populations for adenovirus?
Children (no experience with the virus)
Military Recruits (reactivates under stress)
How does adenovirus enter the cell?
fiber proteins dock and cell is endocytosed (happens very quickly)
How is adenovirus released into cytoplasm of a cell?
Sharp spikes are extremely lytic and lyse endosome and release capsid into cytoplasm
Where does uncoating of adenovirus take place and how?
The slightly degraded capsid (from late endosome) docks with nuclear pore and uncoats, allowing the genome to enter the nucleus
Which DNA pol replicates Adenovirus genome?
The Virus DNA pol
Where does capsid assembly occur in adenovirus lifecycle?
In the nucleus
How does adenovirus egress?
Most likely lysis
Describe the gene expression of adenovirus?
Immediate early phase (transcription factors), Early phase (DNA polymerase), and Late phase (Capsid Proteins)
Can Adenovirus be treated?
Yes, in severe situations when patient is immunosupressed a drug (cidofovir) can be given but is highly nephrotoxic
Can we prevent Adenovirus?
Yes there is a vaccine, but it is only approved for the military.
What epithelial diseases are caused by HPV?
Common warts, plantar warts, genital warts
What malignancies is HPV associated with?
Head and neck cancer, Cervical Cancer, Penile cancer
Where does HPV like to grow? describe its growth
In the basal lamina of epithelium. HPV is very fastidious.
How is the circular DNA of HPV maintained in epithelial cells?
Usually as a episome (like a plasmid)
How does a wart form (describe within context of HPV life cycle)?
HPV infect basal lamina, as skin proliferates the infected cell moves towards surface and begins phenotypical changes. The HPV senses these changes and goes nuts, causing hyperplasia and a wart. Warts are contagious!
Describe HPV genome
What replicates the HPV genome?
The host DNA polymerase
What HPV viral factors are oncogenes?
E6 and E7 (E stands for early)
What phases are HPV genes transcribed, what types of proteins are transcribed in each phase?
Early (functional proteins), Late (Structural capsid proteins)
How can you diagnose HPV?
DNA tests for HPV types
How can you treat warts?
Cryotherapy, chemical ablation, colposcopy (minor surgery)
How can you prevent HPV
There are two approved vaccines that treat high risk strains, they are made of virus like particles composed of empty capsids. They are made up of the late genes and the body develops antibody against them (recognize 3D structure). You must vaccinate before the person has ever been exposed.