Exam 4 - Lecture 8 Flashcards
Know the functions of E6 and how they help PV cause tumor formation
- What is the normal functions of the cellular proteins they impact?
E6 binds to and inhibits the p53 protein, which works to monitor the genome for damage and induces cell death if there is too much damage
Without p53, there are more mutations, no apoptosis, and excessive cell division
E6/E7 don’t directly cause cancer, but they inhibit normal cellular protections so cells mutate/divide uncontrollably
Know the functions of E7 and how they help PV cause tumor formation
- What is the normal functions of the cellular proteins they impact?
E7 binds to and inhibits the Rb protein, which works to prevent cells from moving forward in the cell cycle by blocking a transcription factor called E2F
If there is no Rb, E2F activates cyclins/CDKs which allows for nonstop movement through the cell cycle
E6/E7 don’t directly cause cancer, but they inhibit normal cellular protections so cells mutate/divide uncontrollably
Know the functions of E2 and how they help PV cause tumor formation
- What is the normal functions of the cellular proteins they impact?
E2 functions to limit E6/E7 expression
Noncancerous types of HPV exhibit high levels of E2, while the most dangerous types have little to no E2
Know the functions of E5 and how they help PV cause tumor formation
- What is the normal functions of the cellular proteins they impact?
E5 binds to the EGF receptor and activates its signaling activity, which results in an inhibition of apoptosis and an increase in cell division
What are tumor suppressors vs oncoproteins?
What do the high risk types do with their genome that helps them cause cancer?
The HPV genome usually integrates into the host genome in the types that cause cancer
Adenoviruses
- What do the viruses look like and what types of disease do they cause in humans?
Non-enveloped, icosahedral viruses with dsDNA genome
– have fiber proteins projecting from each vertex
Infections are usually asymptomatic, but can present with cold or flu-like symptoms (infections starts in the adenoids)
Adenoviruses
- What is unique about their capsid and how they interact with the host immune system?
Unusually stable capsids that help make them resistant to chemical agents and pH extremes
An uncanny ability to evade the host immune response
- Blocks interferon response, blocks class I MHC
expression, prevents apoptosis
Adenoviruses
- What are functions of E1A and E1B and why do we not have to worry about them?
E1A blocks Rb, and E1B blocks p53, but this has only been reported to happen in vitro (no human cancers reported)
Polyomaviruses
- What do the virions look like?
Small, non enveloped icosahedral viruses
dsDNA genomes with only about 5000 nucleotides and only code for a handful of proteins
Polyomaviruses
- What disease does JC virus cause?
causes PML or progressive multifocal leukoencephalopathy (slow destruction of brain white matter) ((usually only a problem in AIDS or organ transplant patients))
Polyomaviruses
- What disease does BK virus cause?
causes respiratory illness and kidney failure in
immunocompromised individuals ((major problem in kidney transplant patients))
Polyomaviruses
- What disease does Merkel cell virus cause?
causes Merkel cell carcinoma, an aggressive and rare form of skin cancer
What do polyomaviruses do to cells in cell culture and what role does T antigen play in that?
What was the issue with polyomaviruses w/ respect to the polio vaccine?
