Papillomaviruses and Polyomaviruses Flashcards
1
Q
Shope papillomavirus
A
- First mammalian model of cancer caused by a virus
- Dr. Richard E. Shope
- Ex. possible source of myths about a jackalope (rapid with horns of an antelope)
2
Q
Papillomaviruses and polyomaviruses properties
A
- Naked, icosahedral virions, spherical in outline
- dsDNA
- replication in nucleus
- most have not been cultured, but can TRANSFORM cultured cells
- polyoma: transcribed from both strands
- papilloma: transcribed from one strand
- *may be oncogenic
- Transmitted by contact
3
Q
What is papillomaviruses distinguished based on?
A
- Host range and DNA sequence relatedness
4
Q
Properties of genomes
A
- Similar to human PV
- *generally have multiple genera and multiple serotypes that are species specific
o Usually difficult to grow in vitro
5
Q
How do papillomaviruses replicate?
A
- Pathogens of epithelial cells
o Tightly related to growth of epithelium
o Outside of chromosome in basal layer
o As cell matures the virus matures as well - Infects dermal layer and EARLY gene expression can be detected
- Late gene expression of structural proteins and vegetative DNA synthesis is restricted to TERMINALLY DIFFERENTIATED CELLS OF EPIDERMIS
- **link between cellular differentiation and viral gene expression
6
Q
Papillomavirus replication highlights
A
- Binds proteoglycan and enters through receptor-mediated endocytosis
- Expression of genome is complicated (3 reasons)
- *only 1 strand of genome is transcribed
- 2 classes of proteins produced
- Virions assembled in nucleus, release on death of cell often as a consequence of cellular replacement
7
Q
What are the reasons why the expression of papillomavirus genome is complex?
A
- Multiple promoters
- Alternative splicing patterns
- Link between differentiation and gene expression
8
Q
What are the 2 classes of proteins produced in papillomavirus replication?
A
- Early: non-structural regulatory proteins (trans-acting transcriptional regulators)
- Late: structural
9
Q
Canine papillomatosis
A
- Caused by at least 16 canine PV in 3 different genera
10
Q
What is the most common papillomavirus-induced disease (primarily by CPV-1) in dogs?
A
- Oral papilloma’s
o Typically start on lips
o Spread to buccal mucosa, tongue, palate, pharynx
o Develop 4-8 week AFTER INFECTION
o *most regress within 8 weeks
o Extensive ones require intervention - *clinical diagnosis
11
Q
What does CPV-2 and CPV-6 cause?
A
- Cutaneous papilloma’s=’warts’
o Most common on FEET of young dogs
o Can developed in nailbed epithelium
Cause distortion of claw
Destruction of bone - *Skin trauma and immunosuppression predispose to wart development
- *clinical diagnosis
12
Q
Why do the warts go away?
A
- If squeeze a wart=expose virus to immune system=promote a better immune response
*people will NOT get warts from their dog: species specific!
13
Q
If a dog has an unusual skin lesion, what should you think?
A
- Papillomavirus: more than just regular warts
- *specific staining shows extent of DNA: see it throughout
14
Q
Equine papillomatosis consists of
A
- Warts: EpPV-1 (regress after 1-9 months)
- Aural plagues: EqPV-2 (association with squamous cell carncinoma?)
- Genital papilloma’s: EqPV-2
- **clinical diagnosis
15
Q
How is equine papilloma virus transmitted?
A
- Contaminated fomites (halters, etc), rubbing posts
- Direct contact
o Sexual transmission NOT required for genital papillomas
