DNA Viruses

Question 1

Requires DNA-dependent DNA polymerase

Answer 1

1. Can be viral or cellular

2. If viral - frequent target of antivirals

Question 2

Transcription

Answer 2

1. DNA-dependent RNA polymerase
2. Except for pox viruses, RNA polymerase used is cellular
   A. If cellular, requires replication to occur in the nucleus

Question 3

Parvovirus B19

Answer 3

1. Small, naked, requires replicating cells for infection
2. Infects erythroid precursors
3. Diseases
   A. Aplastic crisis - anemia
   B. Fifth disease - slapped cheek
   C. Fetal death
4. ssDNA**

Question 4

Polyoma viruses

Answer 4

1. Circular genome
2. ds DNA (~5 kB)
3. Small
4. Naked
5. Heat-stable, solubilization-resistant
6. Slow replication cycle
   A. Stim cell DNA synthesis
   B. Replicates in nucleus
7. JC virus -> multifocal leukoencephalopathy
8. BK virus -> nephropathy in transplant recipients
9. Merkel cell virus -> merkel cell skin carcinomas

Question 5

Papillomavirus

Answer 5

1. DsDNA
  A. Small
  B. Naked
2. Disease: warts
3. Early and late gene expression is controlled by differentiation of the epidermis

Question 6

Adenovirus

Answer 6

1. Naked
2. Ds DNA genome
   A. Linear
   B. Repeats on ends
3. Diseases
   A. Acute resp disease
   B. Conjunctivitis
   C. Gastroenteritis
4. Fiber spikes - attachment
5. Usually on mucous membranes

Question 7

Hepatitis B

Answer 7

1. Partially ds DNA genome***
   A. Enveloped- viral surface antigen
   B. Circular
2. Utilizes reverse transcriptionase
3. Viral DNA polymerase -> full strand dsDNA
4. Host RNA polymerase -> mRNA
5. DNA polymerase -> complete dsDNA -> integrated
6. Diseases
   A. Acute and chronic hepatitis
   B. Persistent infections often -> liver cancer

Question 8

Herpesviridae

Answer 8

1. Large ds DNA genome
   A. Linear
   B. Encodes own DNA polymerase
   C. Needs host RNA polymerase
2. Enveloped
3. Ability to establish a latent infection
4. Viruses and diseases
   A. HSV 1 and 2: cold sores, genital herpes
   B. Varicella-zoster: chicken pox, shingles
   C. Epstein-Barr: infectious mononucleosis
   D. Cytomegalovirus: infectious mononucleosis, birth defects
   E. HHV 6 and 7: roseaola infantun
   F. Kaposi sarcoma

Question 9

Pox viruses

Answer 9

1. Large ds DNA
  A. Enveloped
  B. Linear
  C. Replication in cytoplasm 
2. Complex virion structure
3. Encodes own DNA-dependent RNA polymerase
4. Diseases:
  A. Smallpox
  B. Vaccinia
  C. Molluscum contagiosum
  D. Monkeypox

Question 10

DsDNA viruses

Answer 10

1. Polyoma virus
2. Adenovirus
3. Herpesviridae
4. Papilloma
5. Pox