Polyomavirus

Question 1

Why was the discovery of Polyomaviruses so important?

Answer 1

-1st biological entity to be fully sequenced
-1st TF, enhancer, nuclear localization sequence and polyadenylation discovered

Question 2

true or false: sv40 is related to polioviruses

Answer 2

true
-it is because the vaccine for polio was made using monkey kidneys and the vaccine was contaminated with sv40 coming from the monkeys

Question 3

True or false the vaccine for polio cause a huge rise in cancers in the 50s

Answer 3

not really it def has developed cancers in some people but not as much as people anticipated
tho very oncogenic for mouses

Question 4

facts about the polyomaviruses:

Answer 4

-non-enveloped
-icosahedral
-45 nm in diameter
-dsdna 4.5-5.5kb
-circular dna

Question 5

what are the 2 main polyomaviruses in humans

Answer 5

BK virus: kidney epithelium: hemorrhagic cystitis, ureteral stenosis and allograph failure
-JC virus: kidney epithelium and brain oligodendrocytes: progressive multifocal leukoencephalopathy

Question 6

which polyomavirus causes tumors in athymic mice

Answer 6

mouse polyomavirus

Question 7

true or false: polyomaviruses are dangerous for most poeple

Answer 7

false: it is more dangerous for immunocompromised people like people who have aids

Question 8

JC virus

Answer 8

-most important in humans
-known for being dangerous during the aids crisis
Progressive Multifocal Leukoencephopathy (PML)
-5% of AIDS patients have PML
-Is fatal in about 50% of those cases
-can cause dementia and change of personality

Question 9

BK virus

Answer 9

Common early childhood infection.
Can cause mild respiratory or urinary track
disease. Viral DNA is found associated with some types
of cancer.

Question 10

Merkel cell polyomavirus (MCV)

Answer 10

-Recently discovered in 2008. Causes most cases of
Merkel Cell Carcinoma.
-Mostly seen in AIDS patients. cause by immunosupression
-Merkel cells are cells associated with sensory neurons
-5y survival rate

Question 11

which vaccine did sv 40 contaminated

Answer 11

the salk polio vaccine

Question 12

true or false: polyomaviruses are self assembled

Answer 12

true

Question 13

what makes up the structure of polyomaviruses

Answer 13

there is VP1 that makes the outside of the capsid
-VP2 and 3 are more inside and they stick everything together
-it also has histones from the host that wind up the DNA in the capsid

Question 14

facts about the polyomaviruses genome

Answer 14

-they pretty much have the same genome structure (JCV, BKV and sv40)
-well conserved areas like the non-coding regulatory region
-the RR serves as a promoter for the activation of early and late genes (bi-directional)
-It also helps with the regulatory regulation (the early genes help set up the late transcription so that it is more efficient)

Question 15

Functions of virus encoded polyomaviruses proteins:

Answer 15

Early region:
-Large T antigen708
Initiation of viral DNA replication
Stimulation of host DNA synthesis,
Regulation of transcription
-Middle T 421 Cell transformation
-Small T 174 Efficient viral DNA replication (PP2A
binding)

Late region
-VP1 362 Major capsid protein, attaches to
cellular receptors
-VP2 352 Minor capsid protein
-VP3 234 Minor capsid protein
-Agnoprotein 62 Release of viral particles

Question 16

What are the three ways for polyomaviruses to enter the cell

Answer 16

-macropinocytosis
-Clathrin coated pit (most common)
-Caveolea (there is no endosome, the sort of sac stays ph neutral)

Question 17

Where do SV40 binds?

Answer 17

it binds to glycolipids which are pretty much on everycell
-even tho it is low affinity there is a lot of small interactions so it is good at infecting almost any cells

Question 18

which type of receptor does JCV binds

Answer 18

serotonin receptors

Question 19

True or false: BKV uses clathrin coated vesicles

Answer 19

false it used caveolae

Question 20

w does polyomaviruses go to the nucleus

Answer 20

it uses actin cytoskeletons

Question 21

why is the SV40 LgT protein so important

Answer 21

-large T antigen sets up the virus replication so that it is more efficient
-since target cells are not actively dividing it needs to trigger the S phase
-it binds to RB
-has a pol a, rb, chaperone, p53,p300 binding domains
-it a part uses ATP activity for the helicase domain so that it can unwind the DNA properly

Question 22

what is the name of the highly conserved region in polyomaviruses

Answer 22

COre origin TAg binding site 2
-it is the central perfect palindrome

Question 23

how did polyomaviruses solve the end replication problem

Answer 23

by having a circular DNA there is no gap in the lagging strand
-at the 3’end for humans we use the telomerase to put telomeric reoears which are throwaway sequences that we can get rid of easily

Question 24

is the name of the motif which binds to RB

Answer 24

LXCXE
-it binds to rb to free E2F so that it can activate S phase
-it is a highly conserved region in other viruses like HPV
-it is used by a lot of oncogenic DNA viruses to initiate S phase and bind RB