What do all viruses contain?
Protein and nucleic acids
- some have lipid envelope that is embedded with glycoproteins
What are the possible genomic organization of a virus?
RNA both ss and ds
DNA
What are the capsid symmetry of viruses?
icosahedral
spherical
helical
What is the difference between positive and negative ssRNA?
Positive- the genome is Viral mRNA. Can directly make proteins
Negative- the genome is a template for Viral mRNA. Thus you must first make + RNA or mRNA to make proteins
What are the 4 ways to describe a virus?
- Genomic organization
- Capsid Symmetry
- Presence of Envelope
- Tropism
What does tropism mean?
What organisms do the viruses affect
- which tissues do the affect
- because specific molecular structures on viruses need specific proteins on host tissues to bind to to be affective
What hematopoietic cells are affected by viruses?
All
- specific viruses affect specific cell types
What are the steps in viral replication?
- Gaining entry to host cell
- Replicating proteins
- Replicating nucleic acids
- Packaging proteins and nucleic acids into virions
- Exiting the cell
- of note drugs are targeted to affect any of these steps
What is the common MOA of an antiviral drug?
Mimic shape of nucleotide or nucleoside and plug up enzymes that are used for replication.
- drugs must have higher affinity for viral enzymes than host enzymes
What is acyclovir and what does it mimic?
Antiviral that fights against some herpes viruses
- nucleoside analog which is structurally similar to guanosine
- lacks 3’ hydroxyl and thus DNA elongation cannot occur
What is acyclovir in terms of classification and what must happen to it before it becomes active?
Pro-drug
- must be activated by viral thymidine kinase
When in the cell cycle is thymidine kinase expressed and how do viruses get around this?
during S phase
- Viruses carry their own which push the cell into S phase and replication
- HSV does this
- allows virus to replicate in quiescent host cell
What are the phases of viral pathogenies?
Acute: cell death and inflammation
Long term: malignancies and immune suppression
What is a long term complication of Ebstein Barr Virus?
Oral pharyngeal cancer
Lymphoma
What are 2 ways which viruses can cancer?
- Cause cell proliferation
2. Inhibit apoptosis
Where in the cell cycle can viral oncogenes act?
- G1-S phase checkpoint
- The regulation of cell death by apoptosis
- The immunological synapse
When Bid binds Bax what happens?
This allows for pores to form the mitochondrial membrane which then releases Cytochrome C and causes apoptosis
When Bid binds BCL-2 what happens?
Doesn’t allow for release of Cytochrome C and thus no Apoptosis
