L67 Flashcards
What is the genome and viral structure of polyomavirus & HPV?
dsDNA
- Nuclear replication
Naked + icosahedral
What is the presentation of polyoma virus?
Usually nothing!
Only seen in IC pts
Polyoma virus transmission
Respiratory
1ary inoculation of lungs
2ary inoculation of trophic organs
What is the reading frame of polyoma virus vs HPV?
Polyoma = open reading frame on BOTH strands
- Coded in counter vs clockwise fashion accordingly
HPV = reading frame on 1 strand only, therefore coded directionally
How is polyoma virus released from host cells?
Lysis
What are the 3 major parts of the polyoma virus genome?
Early = non-structural
- Large T antigen, inactivates p53 & Rb
Late = structural
Non-coding
What is the polyoma virus that infects the CNS? What disease does it cause?
JC virus PML - Infects oligiodendrocytes - Demyelinating, white matter - "Non-enhancing brain lesions" - Gait, vision, speech changes
What is the polyoma virus that infects the kidneys? What diseases does it cause?
BK virus
Nephropathy
Ureteral stenosis
Hemorrhagic cystitis (more common in stem cell transplant pts)
How is HPV transmitted?
Direct contact of warts - hand to hand or sexual contact
Birth
What are the 3 major regions of the HPV genome?
Early = E1-7 - Cancer proteins Late = structural proteins - L1 = major capsid - L2 = minor capsid LCR region
What are 2 unique features about HPV?
- Can cause cancer
2. Associated with cells at specific stages of differentiation - actively dividing cells
Explain HPV pathogenesis.
Microtrauma
HPV + basal layer epithelium
Codes early genes = host cell growth –> wart
Replicate viral episome with HOST DNApol
Late genes on in terminally differentiated epithelial layers (top, keratinized)
Virus assembles in nucleus - sheds with dead upper layers
What event increases the likelihood of a carcinogenic strain of HPV?
Integration of HPV episome into host cell DNA
- Lose E2
- More direct upregulation of E6&7
Describe how HPV can cause cancer.
@ transition zones Increased: - E6: decreased p53 - E7: degrade Rb Net: loss of regulation of cell cycle, neoplasia
What types of cancer does HPV cause?
Cervical
Oral
Anal - increased in HIV+ gay men