Exam2Lec9DNAviruses Flashcards
What is the genome and structure for the Parvoiridae family of DNA viruses?
-Linear, single stranded DNA
-icosahedral capsid symmetry, non-enveloped
What is required for replication for the Parvoiridae family of DNA viruses?
-Nuclear replication
-Requires S phase for replication thus infects rapidly dividing cells
Examples of viruses of the Parvoiridae family
-Erythrovirus/B19 virus
-Dependovirus/Adeno-associated viruses (AVV)
-Boccavirus
What type of cells does Parvovirus (B19) infect?
Tropism for Erythrocytes
Process of B19 Parvovirus (B19) infection in erythrocytes?
-Binds glycan and glycoproteins receptors
-Entry via receptor mediated endocytosis
Clinical manifestations of Parvovirus (B19)
Fifth Disease/Slap Cheek Disease (erythema infectiosum)
What is Dependovirus also known as?
Adeno-associated viruses (AVV)
What is Dependovirus/AVV dependent on?
Helper virus dependent (adenoviruses, HSV-1, HSV-2, CMV, PRV)
How can Dependovirus/AVV be used?
As gene therapy vectors
Mechanism of Dependovirus/AVV as gene therapy vectors
-Dependovirus genome can integrate into host genome
-Maintenance of genome as episome for < 1 year
What is the genome and structure for the Polyomavirus family of DNA viruses?
double stranded circular DNA & closed, associated with histones
What is the capsid symmetry for polymavirus family?
icosahedral capsid summetry
Where is the polymavirus family replication
nuclear
persistent infection of polymavirus family with little apparent disease can be ______
oncogenic
What are the examples of polymavirus family
Merkel cell virus
BK virus
JC virus
Explain the polymavirus genome
Large T antigen (early gene)
1.activation of RnA synthesis
2. cell cycle progression through S phase
- binging to pRb family, p53 tumor suppressors
3. binging SV40 ori to initiate SNA replication
-early transcription shit off
-late transcription activation
What is the Merkel cell virus cause?
Merkel cell carcinoma (skin)
where is BK virus seen ?
transplant patients
What does the BK virus cause?
ureteric stenosis
polyomavirus associated nephropathy
where is JC virus seen ?
in immunosuppressed people
What does JC virus cause?
Progressive multifocal leukoencephalopathy (PML)
What is the genome and capsid symmetry of Papillomavirus family?
DNA genome - circular ds
icoshedral capsid symmetry
- non enveloped
What is the replication of Papillomavirus family?
Nucelar
What is the transmission of Papillomavirus family?
sexual (skin to skin)
what is the tropism of Papillomavirus family?
keratinocytes differentiation
what does the low risk (6 and 11) of Papillomavirus family?cause:
Genital warts, recurrent respiratory papilomatosis
What does the high risk *16,18,45,46 Papillomavirus family cause?
Cancer-Cervical carinoma
Overview of HPV genome
E1-E7= early genes (nonstructural)
- E6 and 7 proteins play major role in immortal and malignant transformation of infected cells
-E5 has role but not required to maintain cancer phenotype
L1 and L2=late genes (structural)
-capsid genes
-l1 very important for HPV vaccine
URR=upstream regulatory region
E1-E7= early genes (nonstructural)
- E6 and 7 proteins play major role in immortal and malignant transformation of infected cells
-E5 has role but not required to maintain cancer phenotype
L1 and L2=late genes (structural)
-capsid genes
-l1 very important for HPV vaccine
What is used in the HPV vaccines
recombinant L1 capsid proteins of individual HPV types
Adjuvant: aluminum hydro phosphate sulfate
Path of HPV replication
-HPV infection occurs in the basal layer of the epidermis
-Once in the basal layer, relies heavily on E6 and E7 to drive replication of the virus
What monomers are used for HPV assembly and what do they do?
L1= HPV major capsid protein
L2=HPV minor capsid protein
Both are self-assembling
How are HPV VLP vaccines created?
-Use virus like particles, recombinated L1 capsid proteins of individual types
>Quadrivalent (HPV4)
>Nonvalent (HPV9)
What do HPV VLP vaccines protect against?
-Protects against strains
-6,11 (75-90% genital warts)
-16,18 (70% cervical cancer)
-31,33, 45, 52, 58
What is the genome and structure of the Adenovirus family?
DNA genome, double stranded and linear
Icosahedral capsid symmetry, naked
Where is the Adenovirus family replicated?
-Nuclear
How many serotypes does the Adenovirus family have?
> 51 serotypes, each can cause varying symptoms
Transcription process for Adenovirus family?
- Due to linear genome, transcription units encode on BOTH strands of the DNA
- Immediate Early Genes (E1A/E1B) code for regulatory transactivators
- Early Genes (E3-E4) code for viral replication proteins
- Late Genes (L1-L5) code for capsid (structural) proteins
What can adenovirus genome be used for?
Can be used as gene therapy or vaccine vector
Clinical Symptoms and transmission of Adenovirus
Endemic respiratory infection in children (50% asymptomatic)
-Transmission- respiratory (aerosol) and fecal oral (two strains)
List of respiratory infections that affect infants and toddlers due to adenovirus
-Infants: Nasal congestion, rhinorrhea, bronchitis, and pneumonia in colder areas
-Toddlers: Pharyngitis
What are the diseases by serotype for adenoviruses?
-Pharynigitis (Serotypes 1,2,3,5,7)
-Epidemic Keratoconjunctivits (8,18,27)
-Acute infantile gastroenteritis (40,41)
What is the genome and structure of the Herpesviridae family?
DNA Genome: Large, ds, enveloped (studded w/ viral glycoproteins)
Iscohedral capsid symmetry
Where is Herpesviridae replicated?
Nuclear replication
Subfamilies of Herpesviridae family
- Alphaherpesvirinae
- Betaherpesvirinae
3.Gammaherpesvirinae
Explain the viral gene expression for herpesviridae family
Use Immediate early gene code for transactivators
Early Gene–> DNA replication
Late Gene–> Assembly (capsid)
Example HSV-1 Latency
- Migration: virus must travel from site of infection to site of latency
- Maintenance of episome: circular genome in complex with histones
- Latent Associated Transcript: Expressed during latency but not required (HSV-1: single transcript (LAT))
- Stress reactivates the virus
Characteristics of Alphaherpesvirinae
-Efficient destruction of infected cells
-Capacity to establish latent infections primarily in SENSORY GANGLIA
Examples of Alphaherpesvirinae
Herpes simplex virus type-1 and 2 (HSV-1 and -2)
-Causative agents of oral and genital herpes
Varicella Zoster Virus (VZV/HHV-3)
-causative agent for chicken pox and measles
Characteristic of Betaherpesvirinae
-Frequent enlargement of infected cells
-Capacity to establish latent effects primarily in SECRETORY GLANDS, lymphoreticular cells, kidneys
Examples of Betaherpesvirinae
Human Cytomegalovirus (HCMV/HHV-5)
-causative agent of birth effects
Human Herpesviruses 6 and 7 (HHV-6 and -7)
-HHV-6 causes roseola in infants
-HHV-6 integrate into telomeres, associated with neurological defects
Characteristics of Gammaherpesvirinae
-Usually specific for either T or B lymphocytes
-Capacity to establish latent infections primarily in LYMPHOID TISSUE
Examples of Gammaherpesvirinae
Kaposi’s Sacrcoma Herpes Virus (KSHV/HHV-8)
-Causative agent of Kaposi Sacroma
Epstein Barr Virus (EBV/HHV-4)
-Causative agent of mononucleosis Burkett lymphoma, nasopharyngeal carcinoma
What is the genome and structure of the Orthopoxvirus (pox) family?
-DNA genome: ds linear, enveloped
-Complex structure
Where is the pox family replicated?
Cytoplasmic
Examples of pox family viruses
-Variola virus (smallpox)
-infects only humans; fatality ~30%
-Cowpox
-Rodent reservoir (cows, cats, humans are ancillary host)
-Monkeypox
What is Vaccina?
Smallpox vaccine
-Laboratory strain, closely related to rabbitpox
How is monkeypox transmitted and what are the symptoms?
Transmission
-Direct contact, contact with contaminated items, contact with respiratory secretion, vertical transmission
Symptoms
-Enlarged lymph nodes, rash, fever, malaise, chills, pruitis, headache, myalgia