Exam 3 UF virology flash cards

What is the primary cellular trophism for the Hepatitis B virus?

Liver

What kind of genome does HepB have?

Double stranded DNA

What makes Hepatitis' replication special compared to other DNA viruses?

Only DNA virus that packs a reverse transcriptase

What is another name for a viral core?

Nucleocapsid

What are the two types of RNA made by Hepatitis?

Pregenomic RNA

mRNA

What allows for multiple mRNA to be made in hepatitis?

frame shifts

What mechanism for entry does Hepatitis use?

Maybe caviolin induced but not confirmed (probably not on exam)

Where is the viral genome released in Hepatits?

Nucleus

What type of virus makes cccDNA

Hepatitis

What does cccDNA stand for?

covalently closed circular DNA

For hepatitis, does host or viral enzymes make RNA from the DNA?

Host

Typically, free ribosomes make what kind of protein for viruses?

active proteins/enzymes

Typically, ER bound ribosomes make what kind of protein?

Structural

What is another name for the P protein in Hepatitis?

Retrotranscriptase

What propably causes the gap in hepatitis' genome?

Lack of needed nucleotides within the sealed viral capsid

Where does Hepatitits turn its pregenomic RNA into DNA?

Within the sealed nucleocapsid

Where does Hepatitis gain its envelope from?

The ER

RNase H activity does what?

Remove the RNA from its newly generated complementary DNA

Pregenomic RNA binds to what protein in Hepatitis?

P protein/ Retrotranscriptase

How does Hepatitis exit cells?

A vaccuole forms around the enveloped virus, and moves it to the surface of the cell.

Explain the role of Priming and Strand exchange when it comes to Hepatitis replication?

Priming: a small strand of DNA is made on one end of the pregenomic RNA

Strand exchange: the DNA primer is moved to the other end of the pregenomic RNA to be used as a primer for DNA synthesis

Strand exchange: A small amount of RNA is left at the end, and is used moved to the other end of the newly created DNA strand and is used as a primer for (+)DNA synthesis

Hepatitis B makes what protein present in hepatocytes?

MHC1

What protein does CD8 & T cells recognize to determine apoptosis in hepatocytes infected with Hepatitis?

MHC1

What are symptoms of Hepatitis B?

Fever, Malaise (feeling bad in general) Nausea

Inflammed painful liver (hepatomegaly)

Dark urine

Complications of Hepatitis B?

Liver cancer

Postnecrotic Cirrhosis

Liver failure/Chronic liver disease

What could you look for in the blood to confirm somone had HBV?

High blood transaminase

High levels of atypical lymphoctes

How is HBV transmitted?

Needle use

Childbirth

Sex

What % of patients go from acute to chronic HBV?

Only around 20%

What antigen is present during the accute phase of HBV?

HBsAg (HepB surface Antigen)

What antigen is present during the chronic phase of HBV?

HBcAg (HepB core Antigen)

What are always present in the blood during HBV replication?

Viral DNA and the E antigen

What antibodies are present during the accute phase of HBV?

IgM

What antibodies are present during the chronic phase of HBV?

IgG

dsDNA viruses inclue what types of viruses?

Poxvirus

Herpesvirus

Papalomavirus

What viruses use rolling circle replication?

Herpes and papalomaviruses

Which enzymes, viral or host, circularize DNA in rolling circle replication?

Host enzymes

Where do host enzymes nick on the DNA during rolling circle replication?

outside strand

How many times does rolling circle replication go around the DNA loop?

Many times forming one long multigenome chain.

How does the newly synthesized DNA gain its second strand during rolling circle replication?

Host DNApol

How do genomes get seperated after gaining their second strand in rolling circle replication?

Viral enzymes cleave genomes

Where does poxvirus replicate?

cytoplasm

What is a problem poxvirus has to overcome during replication?

No access to DNA replication machinary found inside the nucleus.

Why is the poxvirus a large virus?

Needs to encode for machinary for replication

What does the genome of poxviruses look like?

two hairpins linked together

What are "rabbit ear sequences" in association with poxviruses?

Cleaved ends of the DNA loop allow room for replication machinary to enter, forming a split with two strands of DNA (side by side hairpins) forming a rabbit ear structure.

Know the steps of poxvirus DNA replication

1) nick in the looped DNA

2) formation of rabbit ears

3) replication of genome at exposed area

4) cleavage of 2 viral genomes

How do viruses overcome the fact that not all cells are dividing, and so their DNA replication machinary is turned off?

Encoding proteins that induce cell division

What are the two cylces for the herpes virus?

Lytic and latent

What virus family is associated with a tegument?

Herpes

What is a tegument?

Tegument a relatively amorphous protein filled region unique to herpesviruses. The tegument contains viral proteins and enzymes that play a structural role and are required immediately for viral replication upon intial infection.

What are the two important proteins to know for herpesvirus replication?

Vp16

vhs

What is the role of vhs in herpesvirus?

supresses host gene expression

(viral host supressent)

What is the role of Vp16 in herpes?

transcriptional activator

What model of replication does herpes use?

Rolling cirlce model

How many origins or replication does herpes have?

3

How does herpes enter a cell?

Membrane fusion/endocytosis

What is one notable protein release from the tegument upon entry to the cell?

vhs

What are the 3 temporal periods for herpes replication?

immediate-early, early, late

What is a concatomer?

A long dsDNA peice made up of multiple genomes created by rolling circle replication.

What serves as the template for late genes for the herpes virus

the concatomer serves as the template for late genes

Where is the capsule formed for the herpes virus?

Nucleus

Where does herpes gain its membrane from?

Golgi apparatus

How does herpes leave the cell?

Vacuole transports enveloped virus to surface of the cell

What are poxviruses packaged with?

RNA dependent RNA polemerase

What are the roles of early genes with pox viruses?

Some promote replication in neighboring cells

Some promote uncoating

Some fight host defenses

Which virus recruits a protein from the nucleus of the host to replicate?

poxvirus

Which virus forms a crecent chaped ER?

poxvirus

What virus has a distinctive brick shape?

poxvirus

What are the 3 phases of a poxvirus?

Early, Intermediate, and late

What are taken over to make viral factories for poxvirus?

ER

How is a poxvirus released from a cell

Raft particles formed from membranes taken from golgi aparatus

apoptosis

What are the 2 major types of herpes

HSV1 and HSV2

What type of cells does herpes target?

epithelial

Where does HSV establish latency?

nearby sensory neurons

What virus is associated with a prodrome?

HSV

A patient presents with lesions on the left half of their face and, especially around the mouth. What virus do they probably have?

HSV1

A patient presents with a branching dendratic lesion on their cornea. This is a major sign of what?

HSV eye infection

What are symptoms of HSV?

Blisters

Prodrome

Lesions

Enlarged Lymphnodes

Ulcers around genitals

eye conjunctiva, branching dendratic lesion on cornea

meningitis

How is HSV spread?

through respiratory droplets, body fluid, contact with infected epithelial cells

Triggers of HSV reactivation

Stress

Skin damage

Viral illness

Methods of detection for HSV

wasnt well covered but:

Normal tests, like blood and antibody tests

Lumbar puncture

Can HSV spread asymptomatically?

Yes

Treatment of HSV

anything that ends with -cyclovir

How does HSV medication work

a guanasine that is transformed by viral enzymes to be destructive to the viral DNA

What family is the epstein-barr virus from?

Herpesvirus

What cell types does EBV infect?

Epithelial cells

T cells

B cells are prefered

Typical route of infection for EBV

Infected droplets go into the mouth, replicate in the epithelial cells, make their way towards the tonsils, then is distributed through the lymphatic system

What are some viruses that can cause mono?

CMV

HIV

Toxo

Hepatitis

EBV (90% of cases)

Symptoms on Mono

Fever

Pharyngitis

Lymphandenopathy

exagerated fatigue

splenomegaly (enlarged spleen)

How long is a typical mono case?

4-8 weeks

What are the 3 testing methods of mono?

Monospot (heterophile antibody test)

Anti-VCA antibody test

Anti-EBNA test

When does the anti-EBNA test turn positive?

After an infection of EBV

When does the Heterophile antibody test turn postive

During an active infection of EBV

When does the Anti-VCA test turn positive

Early in infection of EBV and onwards for the rest of your life

What disease does the Varicellia Zoster virus cause?

Chickenpox

Shingles

What family is the VZV virus in?

Hepresvirus

What cell types does VZV infect?

Epithelial cells

Lymphatic cells

T cells

What cells does VZV go dormant in?

Dorsal root ganglion of the spinal cord

How does VSV travel to its target latent cells?

1) Sensory neuron beside epithelial cells

2) move to spinal chord

3) rest in the dorsal root ganglion

What virus is associated with a primary and secondary viremia?

VSV (Varicellia Zoster Virus)