Polyoma, Papilloma, Adeno

Question 1

Which virus families are oncoviruses (cause cancer)?

Answer 1

1. Polyomaviridae
2. Papillomaviridae
3. Adenoviridae
4. Herpesviridae

Question 2

What are the 2 tumor suppressor genes that prevent cancer?

Answer 2

1. Rb
2. p53

Question 3

How does Rb work?

Answer 3

Binds to E2F and prevents activation of cell cycle genes
-cell cycle stops

Question 4

How does p53 work?

Answer 4

Responds to DNA damage by doing apoptosis or stops cell cycle

Question 5

True or false: Only Papillomavirade and Polyomaviridae have proteins that disrupt Rb and p53

Answer 5

False
1. Polyoma
2. Papilloma
3. Adeno
all have proteins that encode proteins that disrupt Rb & p53

Question 6

What pathogens are in polyomaviridae?

Answer 6

1. Human polyomaviruses (10 types, only 1 causes cancer) 10 to 70% of people are infected
2. Merkel Cell polyomavirus (causes cancer)

Question 7

What pathogens are in papillomaviridae?

Answer 7

1. Human papillomaviruses (nearly everyone has been infected, causes warts)
2. HPV16 and HPV18 (cause mostly cervical cancer)

Question 8

Why did identifying HPV causes cervical cancer win a nobel prize?

Answer 8

Identifying that a virus causes cervical cancer we could prevent cancer with a vaccine

Question 9

What group are Polyoma and Papilloma in?

Answer 9

Group 1–>dsDNA

Question 10

True or false: Polyoma and Papilloma are small LINEAR genomes

Answer 10

False
-small
-circular

Question 11

What kind of polymerase do Polyoma and Papilloma use?

Answer 11

HOST DNA dep RNA pol–>Trancscription
HOST DNA dep DNA pol–>replication

Question 12

Where do Polyoma and Papilloma replicate?

Answer 12

Nucleus

Question 13

Are polyoma and papilloma enveloped or non enveloped?

Answer 13

Non enveloped

Question 14

True or false: Polyoma and papilloma have their genome wrapped by host histone proteins

Answer 14

true

Question 15

Life cycle of Polyoma and Papilloma

Answer 15

1. Entry: Endocytosis
2. Capsid disassembly: (+) protein into nucleus –>Early genes
3. Genome Replication–>Late genes
4. Exit: Cell lysis

Question 16

What transcribes early genes (non structural) in Polyoma and Papilloma

Answer 16

Host DNA dep RNA pol

Question 17

What transcribes late genes (structural) in Polyoma and Papilloma

Answer 17

Host DNA dep DNA pol

Question 18

What are the early proteins in Polyoma and Papilloma and 2 function

Answer 18

1. DNA binding and helicase activity
   -Polyoma: T antigen
   -Papilloma: E1 & E2
2. Drives cell cycle progression & transcription
   -Polyoma: T antigen
   -Papilloma: E6 & E7

Question 19

What is an advantage of early proteins driving cell cycle for virus?

Answer 19

-Drive cell cycle so cells get out of G1 phase
-At G1 phase no replication happens
-Progresses cell cycle so polymerase is active & replicates genome

Question 20

What are the late proteins and function function in Polyoma and Papilloma?

Answer 20

-Polyoma: VP1, VP2, VP3
-Papilloma: L1 & L2
-Make capsid proteins

Question 21

Why is it important that Polyomavirus does bidirectional transcription?

Answer 21

So strands do not overlap and make dsRNA
-will cause an immune response

Question 22

Which virus have large T antigen what does it do?

Answer 22

-Polyoma
-host dependent genome replication
-Binds p53 and Rb

Question 23

True of false: Papilloma is studied well in lab

Answer 23

False
-only replicates well in tissues
-causes warts on outer layers–>hard to work with

Question 24

True or false: Polyoma and Papilloma cause cancer frequently

Answer 24

False
-Cancer is off target effect
-Only happens if there is linear integration (mostly E6 & E7 for Papilloma)

Question 25

True or false: Driving cell cycle forward causes cancer

Answer 25

False -it allows for replication -Cancer cells are dead end-->can no longer replicate

Question 26

What group are Adenoviridae in

Answer 26

Group 1-->dsDNA

Question 27

What polymerase does Adenoviridae use?

Answer 27

-Host DNA dep RNA pol (Gene transcription) -Viral DNA dep DNA pol (Gene replication)

Question 28

What type of genome does Adenoviridae have (circular or linear)

Answer 28

Linear

Question 29

Are adenoviridae enveloped/non what is their capsid shape?

Answer 29

-Non enveloped -Icosahedral

Question 30

What pathogens are in Adenovirdae?

Answer 30

Human adenoviruses--> does NOT cause cancer -causes cancer in non humans-->integration not necessary

Question 31

Why are adenovirdae useful?

Answer 31

Broad range of tissue tropism and genes -Gene therapy vectors -oncolytic viruses --> can kill cancer cells -vaccine delivery vectors --> J & J vaccine

Question 32

Adenovirdae life cycle

Answer 32

1. Entry: Endocytosis 2. Capsid dissasembly-->(+) protein into nucelus-->Early genes (HOST DNA dep RNA pol) 3. Genome replication (VIRAL DNA dep DNA pol)-->Late genes 4. Exit by cell lysis

Question 33

Where does protein assembly occur in Adeno

Answer 33

Nucleus

Question 34

Adenoviridae have linear genomes, what problem does this cause when genome replicates?

Answer 34

-Ends can get degraded -Humans solve w/ telomerase -Adeno solves by terminal repeats and is primed by protein TP

Question 35

What 2 proteins do Adeno have that drive transcription forward/manipulate cell and interacts with Rb p53?

Answer 35

-E1A -E1B

Question 36

Adeno have late stage mRNAs that do what?

Answer 36

-Cap independent translation -allows virus to translate when host shuts off cap-dependent translation