Lecture 19 - Herpesvirus Flashcards
What virus is one of the most common ones found in humans?
herpesvirus
Can herpesvirus cause cancer?
yes
What genome does herpesvirus have?
dsDNA viruses
In the herpesvirus virion, what are most viral structural proteins commonly called?
VP = viral protein (nucleocapsid)
What is the HSV-1?
one most common herpesvirus strain
Where do herpesviruses attach to?
cells of the epidermis/dermis of skin and epidermal mucosal cells
How is viral attachment and entry of the herpesvirus achieved?
through a binding receptor and entry receptor
What is the function of VP16?
initiates transcription
What are the early genes herpesvirus transcribes?
genes for DNA synthesis
What are the late genes herpesvirus transcribes?
structural and assembly proteins
What mechanism does herpesvirus use to replicate their genome? What does this result in?
rolling circle replication resulting in linear concatemers of DNA
What does thymidine kinase do and why is it important?
enzyme that increases the pool of dT(thymidine)TPs within a host cell | allow herpesvirus to replicate in slowly dividing or non-dividing cells
What process does the herpes virus use to assemble?
double-envelope process
What is the double-envelope process?
nucleocapsid buds out of nucleus membrane and then gets its second envelope from Golgi apparatus
How can syncytia formation occur with herpesvirus?
glycoproteins can cause fusion between infected and non-infected cells
What is the effect on the host cell due to the double-envelope process?
cell lyses
What is the viral capsid enveloped by? And why?
nuclear membrane to translocate it to the cytoplasm
Where does the nucleocapsid mature?
cytoplasm
Where does the main envelope of the nucleocapsid of the herpesvirus derive from?
Golgi-derived vesicles
After a productive primary infection, where does the herpesvirus travel to become latent?
enters sensory neuron axons and migrates along axon to the cell body in a ganglion in the CNS
What are viral RNA transcripts that are synthesized during latency called?
LATs (Latency Associated Transcripts)
How are LATs beneficial to the virus?
after it undergoes splicing, it plays an important biological role
What type of transport direction is the virus moved within the neuron during latency?
retrograde transport, towards nucleus
What type of transport direction is the virus moved within the neuron during reactivation?
anterograde, down the axon
What 10 factors associate with reactivation of the herpesvirus?
immune suppression | sex | stress | temperature changes | UV light/sunburn | menstruation, pregnancy, lactation | malnutrition | excessive fatigue
What does disease severity depend on (herpesvirus)?
interplay between the virus and its host, especially the host’s immune status
What are 2 methods of transmission of the herpesvirus?
saliva, vaginal secretions, secretions from oral/anogenital tracts (mouth and butthole) | eyes and skin lesions
What are 2 diseases that occur due to infection from herpesvirus?
mucosal lesion | encephalitis
What is the most commonly prescribed antiviral drug for HSV?
acyclovir (ACV)
What does acyclovir do?
acts as a chain terminator, prevents DNA elongation
Which epithelial cells do HSV-1 infect?
oral, skin, cornea
Where in the nervous system do HSV-1 viruses establish latent infections?
trigeminal nerve = spine
Where in the nervous system do HSV-2 viruses establish latent infections?
sacral ganglia
What does the Varicella Zoster virus cause?
chickenpox and shingles
What is chickenpox?
mild diseases affecting kids
What are 3 symptoms of VZV?
fever, malaise, ~300 lesions
What is the mode of transmission of Varicella-Zoster virus?
airborne via cough/sneeze
What happens to the Varicella Zoster virus after the primary infection?
becomes latent in the dorsal root ganglia
What factor increases the risk of reactivation of Varicella-Zoster virus?
aging
List 4 symptoms of shingles.
pain, headache, rash, numb
What are shingles?
reactivated Varicella-Zoster virus after 60yo | common/severe in immunocompromised people
Is there a vaccine available for shingles?
yes
What human herpesvirus causes cancer and 79% of infectious mononucleosis cases?
Epstein-Barr Virus
What is the mode of transmission of EBV? What is it also called?
saliva; kissing disease
What is associated with Burkitt’s lymphoma?
Epstein-Barr Virus
What is cytomegalovirus?
common but show asymptomatic or mild symptoms
How can the cytomegalovirus affect pregnant women?
infect placenta»_space;> fetus
What effects does cytomegalovirus have on the fetus
small brain size | enlarges liver and spleen
What effects does cytomegalovirus have on adults?
hearing loss and mental disabilities
What is Kaposi’s Sarcoma-Associated Herpesvirus (KSAH)?
aggressive pigmented sarcoma on skin | transmitted by saliva
