8. Variola (smallpox)

Question 1

What are the 2 poxviruses of the Chordopoxvirinae subfamily that ONLY infects humans?

Answer 1

Variola virus, molluscum contagiosum virus

Question 2

Amount of deaths caused by smallpox during the 20th century?

Answer 2

300-500 million

Question 3

How is smallpox contracted?

Answer 3

Inhalation

Question 4

What is temporal regulation of transcription?

Answer 4

Process by which specific genes are transcribed at different times, as they are needed

Question 5

Upon variola infection, what protein is needed right away? Why?

Answer 5

DNA-dependent RNA polymerase

To make mRNA

Question 6

3 agents/methods that provided protection from smallpox?

Answer 6

• Inoculation w/ cowpox
• Variolation w/ dead viruses from scabs
• Inoculation w/ vaccinia virus

Question 7

Why does variola package its RNA pol but not its DNA pol?

Answer 7

RNA pol is needed immediately to transcribe mRNA from the (-)RNA genome to translate early proteins

Viral DNA pol is one of the early proteins

Question 8

Variola genome?

Answer 8

Linear dsDNA, ends sealed by hairpin loops (AT-rich)

Question 9

Variola - site of genome replication?

Answer 9

Cytoplasm

Question 10

How is variola spread in the body?

Answer 10

Blood/lymph

Question 11

How is the variola genome protected from host exonucleases?

Answer 11

No free ends since hairpin loops are presented

Question 12

Poxvirus genome replication requires intermediate-gene-specific viral factors and a host factor ______ exported from the nucleus

Answer 12

Vitf2

Question 13

First step in poxvirus replication cycle?

Answer 13

Extracellular enveloped virus (EEV) binds via virion proteins and by glycosaminoglycans (GAGs) on target cell surface

Question 14

3 reasons to study poxviruses even though variola has been eradicated?

Answer 14

• Bioterrorism threat
• Need for better vaccines
• Monkeypox threat