Smiley-5: DNA Viruses Expression and Replication

Question 1

Viral solutions for solving end replication problem (X4)

Answer 1

• use a circular genome
• use circular replication intermediate
• use terminal redundancy to regenerate ends
• use protein primer

Question 2

What virus uses a protein primer?

Answer 2

adenovirus

Question 3

What virus uses terminal redundancy to regenerate ends?

Answer 3

phage T7

Question 4

What virus uses circular replication intermediate?

Answer 4

bacteriophage lambda

Question 5

What virus uses a circular genome?

Answer 5

SV40

Question 6

What type of replication does SV40 use?

Answer 6

theta replication

Question 7

What enzyme separates daughter strand from parents strand in theta replication?

Answer 7

DNA topoisomerase II

Question 8

The center of the replication bubble corresponds to what?

Answer 8

ori

Question 9

What is the only viral protein used by SV40 to replicate its genome?

Answer 9

Large T

Question 10

What proteins does SV40 use for genome replication that are provided by the host? (x7)

Answer 10

• DNAP
• primase
• topoisomerase
• ATPase
• DNA ligase
• DNA helicase
• SSBPs

Question 11

Packaging signals?

Answer 11

sequences at the end of DNA genomes that are involved in packaging progeny DNA into virions

Question 12

What is cos sequence in bacteriophage lambda?

Answer 12

• cohesive ends

- 12 nt complementary ss 5’ protrusions (both 5’ ends)

Question 13

How does bacteriophage lambda replicate its genome (technique)?

Answer 13

rolling circle replication

Question 14

After rolling circle replication, what does the bacteriophage lambda’s genome look like?

Answer 14

long concatemeric DNA (many copies of genome connected end to end) with many DS cos sites

Question 15

What protein recognizes cos sites?

Answer 15

viral terminase (enzyme)

Question 16

What does viral terminase do?

Answer 16

makes staggered SS breaks on cos sites (both strands of DNA)

Question 17

When does cleavage at cos sites occur?

Answer 17

during DNA packaging

Question 18

Terminally redundant?

Answer 18

sequences at one end of genome are repeated at other end as a direct copy

Question 19

What is the protein at 5’ end of adenovirus called?

Answer 19

terminal protein (TP)

Question 20

What does the TP do for adenovirus?

Answer 20

serves as origin and initiator protein

Question 21

Where are the TP proteins linked?

Answer 21

dC residue

Question 22

Function of TP-dC

Answer 22

serves as primer for DNA replication